tag:blogger.com,1999:blog-26580038699270464492024-03-13T09:36:55.507-04:00Kneeless Megafauna"Science is the belief in the ignorance of experts." --Richard FeynmanGreghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-2658003869927046449.post-9126065953627310582013-11-09T21:02:00.000-05:002013-11-13T07:50:09.480-05:00A very high carbohydrate diet for the reduction of elevated non-HDL cholesterol<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Abstract</span></h3>
<div style="margin-bottom: 0in;">
<div style="font-weight: normal; margin-bottom: 0in;">
<br /></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Public
health authorities have for many years recommended diets high in
complex carbohydrates for weight loss and prevention of heart
disease. However, the research literature does not uniformly support
the view that a replacement of fats, including saturated fats, with
carbohydrates in the diet necessarily results in beneficial changes
in cholesterol levels or heart disease risk. While very low
carbohydrate diets have sometimes been observed to result in
favorable changes to cardiovascular risk factors (due to the
increases in HDL and decreases in fasting triglycerides often
observed on those diets), there have been reports that, in a subset
of the population, a very low carbohydrate diet may result in large
increases in potentially atherogenic non-HDL cholesterol.</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
reported studies to date have not been designed to investigate what
happens to an individual with high non-HDL cholesterol who
transitions from a long-term very low carbohydrate diet to a very
high carbohydrate, non-vegetarian diet. The present study was
designed to address that question using the author as the sole
subject.</span></span></div>
<br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Results:
Transition from a very low carbohydrate diet to a very high
carbohydrate diet resulted in a rapid and dramatic reduction in
non-HDL cholesterol. Improvements were also seen in oxidized
lipoproteins, uric acid, and postprandial fat and carbohydrate
metabolism. Seasonal allergies, which were virtually eliminated
on the very low carbohydrate diet, returned upon adoption of the very
high carbohydrate diet. No other deleterious effects were
observed other than an increase in homocysteine, which was reversed through B-vitamin supplementation, suggesting the diet as
implemented provided inadequate B vitamins. The diet is inexpensive
and sustainable, though long-term effects (beyond 7 months) are not
yet known.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">The
short version</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span><br />
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><span style="color: black;">You
can </span><a href="http://vimeo.com/73435170">watch my talk</a><span style="color: black;"> about this experiment at the New York Quantified Self meetup on
Stephen Dean's Vimeo page. Note that this talk was given before I
received my follow-up blood work showing the normalization of my
elevated homocysteine and inflammatory markers.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span></div>
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Introduction</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
present study was designed to measure the effects, primarily on blood
lipids, of a 4-month very high carbohydrate, non-vegetarian dietary
intervention (>65% carbohydrates on average) following several
years of consumption of a very low carbohydrate diet, under
approximately isoenergetic conditions (i.e. the intervention was
adjusted to preserve pre-intervention body weight).</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
study measured HDL and non-HDL cholesterol and a variety of other
biomarkers. Note that, while blood lipids may be considered "risk
factors" for heart disease, changes in these numbers do not
necessarily represent a change in actual risk for heart disease. This
study was not designed to detect changes in actual heart disease
(which I don't have), and therefore I will say no more about actual
heart disease in this write-up.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span></div>
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Conventional wisdom on carbohydrate
consumption</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Mainstream health authorities
typically recommend a high level of dietary complex carbohydrate
consumption. For example, the DASH diet (Dietary Approaches to Stop
Hypertension) has been reported as including approximately 58%
calories from carbohydrates (<a href="http://vimeo.com/73435170">Swain et al 2011</a> “Characteristics of
the diet patterns tested in the optimal macronutrient intake trial to
prevent heart disease (OmniHeart): options for a heart-healthy diet”)
and the TLC (Therapeutic Lifestyle Changes) diet recommends between
50% and 60% carbohydrate (<a href="http://andevidencelibrary.com/files/Docs/Doucette_Kren%20WM%20DPG%20spring%2007.pdf">Doucette and Kren</a>, “The efficacy of using
the Therapeutic Lifestyle Changes diet for reducing comorbidities
associated with overweight and obesity”).</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<span style="font-family: Times, Times New Roman, serif;">Some scientific research has cast doubt
on the benefits of high carbohydrate consumption. For example, Walter
Willett of the Harvard School of Public Health has argued that the
substitution of saturated fat for carbohydrates is neutral from the
perspective of heart disease risk. Based on a variety of dietary
intervention studies, Willett argues that a decrease in saturated fat
and a corresponding increase in dietary carbohydrate should result in
an increase in fasting triglycerides and a decrease in HDL
cholesterol (see e.g. <a href="http://www.ncbi.nlm.nih.gov/pubmed/22658146">Baum et al</a>, "Fatty acids in cardiovascular health and disease:
A comprehensive update"). These changes, which are considered deleterious, should compensate
from the perspective of heart disease risk for the increase in
non-HDL cholesterol, if any, that may be associated with the consumption of
saturated fat. Other research implicates carbohydrates as a causative
factor in the development of small, dense LDL particles, which are
argued to be especially atherogenic (see <a href="http://www.ketotic.org/2013/09/the-ketogenic-diet-reverses-indicators.html">this writeup</a> at <a href="http://ketotic.org/">ketotic.org</a> for a summary of this research).</span><br />
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">In addition to potentially deleterious
changes in HDL and triglyceride levels, advocates of low carbohydrate
diets argue that consumption of a high carbohydrate diet will result
in dangerous spikes in blood sugar as large quantities of
carbohydrates are broken down to glucose and absorbed into the
bloodstream (see, e.g. Jimmy Moore, Cholesterol Clarity, page 214,
quoting Dr. Dominic D'Agostino).</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Finally, research by Sharman et al
(which I <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">summarized previously</a>) suggests that a
high carbohydrate diet could cause deleterious changes in
postprandial fat metabolism.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><span style="color: black;">Because
of this pre-existing research, this study was also designed to test
the effects of the dietary intervention on </span><span style="color: black;">postprandial
</span><span style="color: black;">blood
sugar and triglyceride levels.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Review of a few long-term
dietary interventions</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Let's
say you are an astronomer. You are working on a project that requires
a long term observation of a particular celestial object. So you
program your telescope to collect a year's worth of data on the
object only to discover, at the end of the year, that the telescope
had been looking at the wrong part of the sky. So do you analyze and
publish the data you have, or do you start over and make sure your
telescope is looking at what you wanted to study in the first place?</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Now
imagine you are a diet researcher...</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">I
reviewed a sampling of dietary intervention trials lasting 12 months
or longer to see what, if anything, they say about very high
carbohydrate diets versus very low carbohydrate diets. This was based
on a quick search and should not be considered comprehensive review.</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">I
did not find the reported research to be terribly useful for the
present study. With the exception of a series of papers examining the
very low fat Ornish diet, none of the studies seemed to achieve a
large enough difference in macronutrient intake between the different
groups study participants (or between the study participants at
baseline and at the end of the intervention) for me to consider them
relevant to my experiment (which involved a change in fat consumption
from approximately 60% to approximately 10%, excluding fat from
fish). (Note: I excluded a number of studies by Caldwell
Esselstyn because of his aggressive use of cholesterol-lowering
drugs).</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
table below shows the
percentages of fat consumption in highest vs. lowest fat consuming
study subjects. In cases where there was no control group, the
baseline diet is used for comparison. Diet-induced changes in HDL and
LDL cholesterol are also noted. I did not summarize changes in
triglycerides but they generally show the same trends as HDL – studies that showed an increase in HDL generally showed a decrease in fasting triglycerides.</span></span></div>
</div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-eQMD8O9TJIY/Un2nMc_s-rI/AAAAAAAAASk/VpWQQbcspYE/s1600/diet-studies.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://3.bp.blogspot.com/-eQMD8O9TJIY/Un2nMc_s-rI/AAAAAAAAASk/VpWQQbcspYE/s1600/diet-studies.png" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="text-align: start;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">Summary of changes in HDL and non-HDL cholesterol at conclusion of selected long-term dietary intervention studies. *Silberman et al fat consumption percentage was calculated from reported grams of fat consumed per day assuming a 2,000 calorie diet.</span></span></td></tr>
</tbody></table>
</div>
</div>
<div style="margin-bottom: 0in;">
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">References: </span><span style="font-family: Times, 'Times New Roman', serif;"><a href="http://www.ncbi.nlm.nih.gov/pubmed/12761365">Foster 2003</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/15148064">Stern 2004</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/17341711">Gardner 2007</a>, <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCwQFjAA&url=http%3A%2F%2Fwww.nejm.org%2Fdoi%2Ffull%2F10.1056%2FNEJMoa0708681&ei=oqZ9Usy9JbKvsQSc1oDwBA&usg=AFQjCNE6uQQG-YhWrXItqpULsgzEpJZzZA&sig2=r3M13ZOTYrRRYtA1iuPlZQ&bvm=bv.56146854,d.cWc">Shai 2008</a>, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699720/">Davis 2009</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/20679559">Foster 2010</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/20232608">Silberman 2010</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/22258266">de Souza 2012</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/22562179">Guldrand 2012</a>.</span><br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-weight: normal;"><br /></span></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Note:
the Silberman (Ornish) subjects started out on a very low fat diet,
and they transitioned to a diet much lower in fat. Even their
starting level of fat consumption is far lower than anything achieved
in the other “low fat” interventions summarized above.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<span style="font-family: Times, Times New Roman, serif;">The
other studies could charitably be described as at best “mildly
effective” in achieving their dietary objectives. The numbers shown
in the table above for final macronutrient ratios are generally based
on surveys conducted on the participants at the conclusion of the
study (except for Foster, who did not survey the dieters in either
study and therefore apparently doesn't know what the subjects were
actually eating). There is a rather telling comment in<span style="color: black;"> </span><span style="color: #0000e9;"><u>de
Souza et al 2012</u></span><span style="color: black;">: </span>"despite
the intensive behavioral counseling in our study, macronutrient
targets were not fully met, which complicated the interpretation of
our null result." So they told different groups of people to eat
different diets, but they all ate basically the same diet. Their
outcome measures did not differ between groups at the end of the study (the “null
result”), and therefore interpreting the data is “complicated.”
Let me suggest, actually, that interpreting their data is "a
waste of time." (They published it anyway, of course.)</span><br />
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">By
the way, the Silberman study on the Ornish diet had 2,974 people in
the intervention group (it was not a controlled trial). It is
interesting that the Ornish researchers appear to be able to get
people to actually eat very low fat diets, while other researchers
seem to have more trouble getting participants to make such dramatic
diet and lifestyle changes. I'm not commenting one way or the other
on the Ornish plan, but it is a bit disappointing that the other
research groups don't seem to be able to effect such large changes in
macronutrient intake in their study participants. This means the
published studies are not especially helpful in evaluating diets at
the extreme ends of the macronutrient spectrum.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">A
number of the Ornish studies observed short term reductions in HDL.
However, the longer studies seem to indicate that those HDLs rise
again over the long term (3-5 year timeframe). What is potentially
more troubling, however, is that the Ornish studies do not seem to
report a meaningful reduction in fasting triglycerides.</span></span></div>
</div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<span style="color: black; font-family: Times, 'Times New Roman', serif;">In
2004, </span><span style="color: #0000e9; font-family: Times, 'Times New Roman', serif;"><u>Yancy
et al</u></span><span style="color: black; font-family: Times, 'Times New Roman', serif;"> </span><span style="font-family: Times, 'Times New Roman', serif;">ran
a study of a very low carbohydrate ketogenic diet for 24 weeks. Two
of the subjects (out of 59) on the low carbohydrate diet dropped out
because of sudden increases in non-HDL cholesterol. Overall, 30% of
the subjects on the very low carbohydrate diet experienced an
increase in LDL cholesterol of 10% or more, compared to 16% of
subjects on the low fat diet (this difference was not statistically
significant). Because of its short duration, this study did not
qualify for inclusion in the summaries above. However, it does
support the hypothesis that a very low carbohydrate diet can raise
LDL in a minority of the people who try it (unfortunately Yancy et al did not report non-HDL levels in these individuals, which would have been much more useful). This is also supported by
anecdotal reports from individuals consuming very low carbohydrate
diets. As far as I know a study designed to test this hypothesis has
not been conducted.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Fish oil studies</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">A
number of studies have investigated the effects of fish oil
supplementation on risk of cardiovascular disease. These have not
always found fish oil to be beneficial (see e.g. <a href="http://www.ncbi.nlm.nih.gov/pubmed/23656645">Risk and Prevention Study Collaborative Group</a> "n-3
fatty acids in patients with multiple cardiovascular risk factors"
finding no benefit for cardiovascular mortality or morbidity).
However, these studies generally involve very low doses of fish oils,
on the order of 1 gram of total n-3 fatty acids per day. A study
will find no benefit if it uses an intervention that is too small, but this of course tells you nothing about the effects of a larger dose.</span><br />
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<span style="font-family: Times, Times New Roman, serif;">Some
studies using a larger dose (e.g. <a href="http://www.jlr.org/content/29/11/1451">Harris et. al.</a> Journal
of Lipid Research 1988, which used 24-28g omega-3 per day, and <a href="http://www.ncbi.nlm.nih.gov/pubmed/3990714">Phillipson et. al.</a>, New England Journal of Medicine 1985, which used approximately 20-25g omega-3 per day) have shown
a dramatic improvement in metabolic markers, including total and
non-HDL cholesterol, but these studies were short term and not
designed to observe changes in heart disease. Based on this I believe
it is more likely than not that a dose sufficient to improve
metabolic markers is likely to also have beneficial effects against
heart disease. The present intervention involves a very large intake
of n-3 fatty acids from fish.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Dietary
cholesterol recommendations</span></h3>
</div>
<h3>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif; font-size: small;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">It
is commonly heard that dietary cholesterol has at most a small
relationship to blood cholesterol levels. This seems to be the case
when cholesterol intake is high at baseline. For example, Ancel Keys
suggested that a reduction in dietary cholesterol from 600 mg to 300
mg per day on a 2,000 cal/day diet would be expected to result in a
reduction in total serum cholesterol of only 7.6 mg/dl ("<a href="http://ajcn.nutrition.org/content/40/2/351.short">Serumcholesterol response to dietary cholesterol</a>," American Journal
of Clinical Nutrition 1984). According to Keys, the relationship
between dietary cholesterol and serum cholesterol is stronger at
lower levels of dietary cholesterol intake. Regardless of the
strength of this relationship, public health authorities continue to
recommend a reduced cholesterol diet as a preventive measure for
cardiovascular disease. The recommendation in the <a href="http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm">2010 DietaryGuidelines for Americans</a> is <300mg/day.</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif; font-size: small;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-size: small;"><span style="font-weight: normal;">The figure below is reproduced from Endocrinology and Metabolism, Third Edition (Felig, Baxter and Frohman, McGraw Hill 1995, page 1368). It shows (hypothetically, I presume) the relationship between dietary
cholesterol and serum cholesterol. Consistent
with the Ancel Keys paper cited above, the curve has a decreasing
slope as dietary cholesterol increases, eventually leveling out. This
sort of pattern might be expected with a regulated biological
process, where the body seeks to maintain serum cholesterol at a
particular level regardless of input. In that case, the "ceiling," where the curve flattens out, may tell us something about what the
regulatory system is trying to achieve.</span></span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;"><br /></span></span>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-4wxc8Ml4DBQ/Un6ZXCo3FfI/AAAAAAAAAS0/Y6FreOrvU98/s1600/felig+cholesterol+figure.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="358" src="http://3.bp.blogspot.com/-4wxc8Ml4DBQ/Un6ZXCo3FfI/AAAAAAAAAS0/Y6FreOrvU98/s400/felig+cholesterol+figure.png" width="400" /></a></div>
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;"><br /></span></span></div>
</h3>
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Personal motivation</span></h3>
<div style="margin-bottom: 0in;">
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;"><br /></span></span>
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">Why
did I do this? I have been tracking my cholesterol levels over the
past few years since they have been generally higher than what is
considered normal by mainstream medical opinion (without making any
judgements about the validity of that opinion). In addition, since
adopting a low carbohydrate diet in 2009, I have observed a slow but
persistent trend towards increased total and non-HDL cholesterol.
Therefore, I have tried a number of interventions to bring those
numbers down. My intention is not to allow the blood lipid numbers to
dictate my dietary choices. However, I believe an understanding how
diet affects my blood lipids is useful information for making better
choices about what to eat. I'd like to take into account all
potentially relevant information.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;"><br /></span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-weight: normal;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">I
first tried a low carbohydrate diet after reading <a href="http://www.amazon.com/Good-Calories-Bad-Controversial-Science/dp/1400033462/ref=sr_1_1?s=books&ie=UTF8&qid=1286302951&sr=1-1">Good Calories, BadCalories</a>, just to see what would happen. It caused a number of health
improvements right away. During this time I noticed (with a
glucometer) blood sugar spikes after carbohydrate-containing meals
and was not sure if they were within a healthy range. I stayed on the
low carb diet because I felt fine and it seemed to have improved my
health. However, I had never tried a very high-carbohydrate diet and
wanted to see what would happen.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Hypotheses</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">This study was designed to test the
following hypotheses:</span></div>
<div style="margin-bottom: 0in;">
</div>
<ol>
<li><span style="font-family: Times, Times New Roman, serif;">A high carbohydrate,
low fat diet can meaningfully reduce non-HDL cholesterol</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">An increase in dietary carbohydrate
lowers HDL and raises fasting triglycerides</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">High carbohydrate diets cause
excessive spikes in blood glucose throughout the day</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">High carbohydrate diets impair
postprandial triglycerides after an oral fat tolerance test</span></li>
</ol>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The diet, timeline and measurement
protocol were designed to evaluate these hypotheses. Based on prior
review of the scientific literature, I thought the first hypothesis
was false and the others were true.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Design and Methods</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The study consisted of a single dietary
intervention phase conducted after long-term consumption of a very
low carbohydrate baseline diet (total carbohydrate intake averaging
less than 75g/day).</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Approval of an Institutional Review
Board was not required for this n=1 self-experiment. The author's
mother and girlfriend were informed of the study design in passing
and they raised no ethical concerns. The study was conducted
according to ad hoc human subjects research guidelines made up on the
spot by the author, and reviewed and approved by the author as the
sole human subject.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Baseline diet</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The baseline diet consisted primarily
of whole eggs (3-4/day), grass-fed red meat (450g/day on average),
butter (1/2 stick/day on average), almonds (30g/day on average),
non-starchy vegetables, and coffee (2 cups/day). For approximately
four weeks before the start of the intervention phase, carbohydrate
consumption was gradually increased to approximately 150g/day by the
addition of bananas to the baseline diet.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">The intervention diet</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The intervention diet consisted
primarily of white basmati rice (Swad "premium quality" <a href="http://www.amazon.com/Swad-Rice-Basmati-10-pounds/dp/B003EUAW4M/ref=pd_sim_sbs_gro_1">Dehraduni aged basmati rice</a>) and frozen wild coho or sockeye salmon (Trader Joe's). In
addition, a typical day included approximately one bunch of bananas
(1-2 pounds), 9.5 oz of grass fed whole milk yoghurt (<a href="http://www.grazinangusacres.com/">Grazin' AngusFarms</a>), 1 oz almonds, some sort of shellfish once or twice a
week, and a variety of green vegetables. A few meals a week would be
at restaurants and consist of whatever I wanted. The amount of rice
consumed varied to meet caloric needs and varied between approximately 450g and 565g (dry). Target vegetable intake was determined to roughly meet vitamin
requirements according to US daily reference intakes, but in practice
the requisite amount of green vegetables was often not achieved.
During peach, apricot, and cantaloupe season here in the Northeast
U.S., I ate, respectively, a lot of peaches, apricots and cantaloups.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-1LVUVvqTfCI/Uj30AvfUMtI/AAAAAAAAAQA/gcBAU4j9iKk/s1600/_P1A3194.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" height="266" src="http://2.bp.blogspot.com/-1LVUVvqTfCI/Uj30AvfUMtI/AAAAAAAAAQA/gcBAU4j9iKk/s400/_P1A3194.jpg" width="400" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Times, Times New Roman, serif; font-size: small; text-align: -webkit-auto;">1.75 pounds of white basmati rice. 1 pound of fish.</span></td></tr>
</tbody></table>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="font-weight: normal; margin-bottom: 0in; text-decoration: none;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Carbohydrates:
I was looking for a relatively low-glycemic carbohydrate source. I
thought I would avoid sweet potatoes as they had <a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html">appeared to lower myHDL</a> in a prior short-term experiment. So I went with white
rice, a common global staple food. Basmati rice is reputed to have a
low glycemic index relative to other forms of rice, and I live a few
blocks from a South Asian neighborhood and therefore have a
convenient supply of high quality Indian rice in ten pound bags.</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in; text-decoration: none;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><span style="text-decoration: none;"><span style="font-weight: normal;">According
to my Endocrinology and Metabolism textbook (Felix, Baxter and Frohman, 3rd Ed.), the increase in fasting triglycerides and
corresponding decrease in HDL commonly observed in a high
carbohydrate dietary intervention occurs only when carbohydrate
intake is increased abruptly, and does not occur with a gradual
transition period (see page 1372). Therefore, the present study utilized a wash-in
period of several weeks during which carbohydrate consumption was
increased gradually from ~75g/day to ~150g/day.</span></span></span></span></div>
<div style="font-weight: normal; margin-bottom: 0in; text-decoration: none;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in; text-decoration: none;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Protein:
The intervention diet was designed to have approximately the same
protein content as the baseline very low carbohydrate diet. I use the
“one gram of protein per pound of body weight” rule of thumb
which is widely followed for active individuals looking to build or
maintain muscle mass (approximately 150g/day). Given the
somewhat mixed evidence on dietary cholesterol, I wanted to try
keeping cholesterol intake relatively low while obtaining this amount
of protein. Therefore, fish (primarily salmon and trout) was chosen
as a compromise between cholesterol content and high-quality, whole
food protein. Because of the target protein consumption, cholesterol
intake somewhat exceeded the mainstream guidelines for cholesterol of
300mg per day (see the <a href="http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm">2010 Dietary Guidelines for Americans</a>). Since I
was aiming to achieve my target protein requirements by eating fish,
I did not need to eat any of the "protein" sources such as
tofu, quinoa, beans, etc. that are commonly consumed on other low fat
and vegetarian diets.</span></span></div>
<br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Fiber:
The diet as implemented is relatively low in fiber. I briefly looked
into the research on fiber and did not feel compelled to go out of my
way to consume it. Because of that I chose white rice as my staple
carbohydrate instead of brown.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Measurements</span></h3>
</div>
</div>
<h3>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif; font-size: small;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">Periodic
measurements of total and HDL cholesterol were taken with a
<a href="http://www.cardiochek.com/products/professional-strips/device-a-printer">CardioChek PA</a> meter. In addition, after 8 weeks of the
intervention diet, a comprehensive blood and urine analysis was
performed, including <a href="http://www.thevaptest.com/">Atherotech VAP</a> lipoprotein testing (Shiel
Medical Laboratories, Brooklyn, NY) and compared with a similar panel
taken one year prior during the baseline diet (high in red meat,
butter and green vegetables but excluding grains, legumes and
non-butter dairy).</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif; font-size: small;"><br /></span></div>
</h3>
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Postprandial testing</span></h3>
<h3>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif; font-size: small;"><br /></span>
<span style="font-family: Times, 'Times New Roman', serif; font-size: small;">After
adaptation to the very high carbohydrate diet for at least 8 weeks, I
conducted a number of postprandial tests. First was a standard oral
glucose tolerance test using 75 grams of glucose (<a href="http://www.kalustyans.com/">Kalustyan's</a>, New
York, NY) dissolved in New York City tap water.</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif; font-size: small;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">I
also attempted a “real food” torture test by adding a 9"
cantaloupe to a typical dinner of wild salmon. I have no idea how
much glucose was in that particular cantaloupe but I believe it must
have been substantially more than 75 grams. In order to simulate
“worst case” conditions, I wolfed it down as fast as possible,
which took about 10 minutes.</span></span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif; font-size: small;"><br />
</span></div>
<div style="font-weight: normal; margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif; font-size: small;">In
order to test my hypothesis about the effects of a very high
carbohydrate diet on postprandial triglycerides, I conducted an oral
fat tolerance test based on a typical breakfast I consumed during the
last year of my low carbohydrate diet. This consisted of four eggs
(<a href="http://grazinangusacres.com/">Grazin' Angus Farms</a>) cooked (over easy) in coconut oil, plus
half a stick of butter. This is more fat, more saturated fat and more
cholesterol than is typically used for oral fat tolerance tests in
research settings, though contrary to most researchers I did not
include any carbohydrates (or wheat) in my test. For these reasons my
results will not be directly comparable to any oral fat tolerance
test from the research literature (which is just as well, because, due to lack of standardization, published results are rarely comparable to each other). However
it does have the virtue of being directly comparable to oral fat
tolerance tests I have performed on myself and <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">written about before</a>. I have noticed previously that triglycerides after a meal
may be very low on the day after heavy exercise. Therefore I
conducted my oral fat tolerance test for this experiment on a day
after a day on which no heavy exercise was performed.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Analysis</span></h3>
<span style="font-family: Times, 'Times New Roman', serif; font-size: small;"><br /></span>
<span style="font-family: Times, 'Times New Roman', serif; font-size: small;">Results
were recorded using the iPhone Notes app and bits of paper and
plotted in R. Statistical analysis was not considered necessary or
useful for this experiment. I also did not need WiFi, Bluetooth, a
proprietary machine learning algorithm, The Cloud, Web 2.0, or any
other fancy technology.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Results</span></h3>
</div>
</h3>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
Executive Summary</span><br />
<span style="font-family: Times, Times New Roman, serif;"><br /></span>
<span style="font-family: Times, Times New Roman, serif;">I observed the following changes on the intervention diet compared to baseline:</span></div>
<div style="margin-bottom: 0in;">
</div>
<ol>
<li><span style="font-family: Times, Times New Roman, serif;">Very large decrease in non-HDL
cholesterol, LDL cholesterol and oxidized lipoproteins</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">No change in HDL cholesterol or
fasting triglycerides</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">decrease in serum uric acid</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">No adverse postprandial responses to
high carbohydrate or high fat meals</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">Seasonal allergies returned</span></li>
<li><span style="font-family: Times, Times New Roman, serif;">Intervention diet (as implemented)
may be insufficient in B vitamins</span></li>
</ol>
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Cholesterol levels</span></h3>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The figures below show my non-HDL and
HDL cholesterol levels during the baseline (low carbohydrate, red)
and intervention (high carbohydrate, blue) diets. The reduction in
non-HDL was immediately evident by the first measurement, which was
taken after only 7 days on the high carbohydrate diet. No clinically
meaningful change is evident in HDL cholesterol.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://1.bp.blogspot.com/-Qr25fnDa7Xk/Uj4Vj1Ux1fI/AAAAAAAAARQ/UDsWAkcbQBY/s1600/hicarb-non-HDL.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://1.bp.blogspot.com/-Qr25fnDa7Xk/Uj4Vj1Ux1fI/AAAAAAAAARQ/UDsWAkcbQBY/s1600/hicarb-non-HDL.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Non-HDL cholesterol on baseline (low carbohydrate, red) and intervention (high carbohydrate, blue) diets.</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://4.bp.blogspot.com/-csTANQoua4Y/Uj4VpsCKxcI/AAAAAAAAARY/ypAOIZkydtU/s1600/hicarb-HDL.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://4.bp.blogspot.com/-csTANQoua4Y/Uj4VpsCKxcI/AAAAAAAAARY/ypAOIZkydtU/s1600/hicarb-HDL.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">HDL cholesterol on baseline (low carbohydrate, red) and intervention (high carbohydrate, blue) diets. The increase in the 2.5-3.5 year period roughly corresponds with high butter consumption. Note the downtrend towards the later part of the high-butter period.</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, Times New Roman, serif;"><br /></span>
<br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Fasting
triglycerides were essentially unchanged (57 on 4/3/2012 to 63 on
5/31/2013).</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Advanced lipid testing</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Direct LDL measurements performed on
April 3, 2012 (on the baseline diet) and again on May 31, 2013 (after
8 weeks on the very high carbohydrate diet) revealed a decrease in
total LDL (direct measurement via the Atherotech VAP) from 190 mg/dl
to 77 mg/dl.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://2.bp.blogspot.com/-R1CMSAoTVMc/Uj4VukAImLI/AAAAAAAAARg/lhJJBSYciCk/s1600/lipid-fractions.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://2.bp.blogspot.com/-R1CMSAoTVMc/Uj4VukAImLI/AAAAAAAAARg/lhJJBSYciCk/s1600/lipid-fractions.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Results of advanced cholesterol testing (Atherotech VAP).</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Oxidized LDL and HDL</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Along with the decrease in non-HDL
cholesterol, oxidized LDL decreased from 62 to 35 mg/dl and oxidized
HDL decreased from 36 to 19.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Blood sugar control</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The figure below shows the results of
an oral glucose tolerance test done on the morning of June 7, 2013.
My blood sugar reached a peak of 152 at 45 minutes and returned to
baseline within 2 hours.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://1.bp.blogspot.com/-APHEkAv9qUc/Uj4V0oC7YEI/AAAAAAAAARo/5DMwzBSc55Y/s1600/ogtt.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://1.bp.blogspot.com/-APHEkAv9qUc/Uj4V0oC7YEI/AAAAAAAAARo/5DMwzBSc55Y/s1600/ogtt.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Blood sugar in response to an oral glucose tolerance test containing 75 grams of Kalustyan's glucose dissolved in New York City tap water.</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The figure below shows my blood sugar
over most of a typical day (in this case, May 28, 2013). The majority
of my carbohydrate consumption was in the late morning and over lunch
(12-1 pm). For reference, approximately 4 bananas and two pounds
(cooked) of basmati rice were consumed before 1 pm. As you can see,
no abnormally high or low blood sugar levels were observed. The
highest reading for the day was 126 mg/dl.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://4.bp.blogspot.com/-eGxh7nzFkbM/Uj4V9vMoEQI/AAAAAAAAARw/v8jO5ZSG3PI/s1600/bs-fullday.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://4.bp.blogspot.com/-eGxh7nzFkbM/Uj4V9vMoEQI/AAAAAAAAARw/v8jO5ZSG3PI/s1600/bs-fullday.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Blood sugar readings over the course of a typical day on a very high carbohydrate diet.</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, Times New Roman, serif;"><br />
<br />
</span><br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Hemoglobin
a1c is a measure of glycated hemoglobin. It varies from person to
person and may also depend on average lifespan of red blood cells, so
it has some limitations as a biomarker, but it is considered a useful
measure of heart disease risk, to the extent that it may be mediated
by long-term elevations in blood sugar. This year, after two months
on the high carbohydrate diet, my hemoglobin a1c was ever so slightly lower than it has been previously on the low carbohydrate
diet (5.6% on 4/3/2012 vs. 5.5% on 5/31/2013).</span></span></div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
standardized 9” oral cantaloupe tolerance test resulted in a
maximum postprandial blood sugar of 107.</span></span></div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Triglycerides</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Below are the results of an oral fat
tolerance test conducted on July 30, 2013 according to the protocol described above.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://3.bp.blogspot.com/-33ObGAtuuLY/Uj4WDnsIOkI/AAAAAAAAAR4/iVQbcmUpKzM/s1600/hicarb-oftt.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" src="http://3.bp.blogspot.com/-33ObGAtuuLY/Uj4WDnsIOkI/AAAAAAAAAR4/iVQbcmUpKzM/s1600/hicarb-oftt.png" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Triglycerides before (t=0) and after (t=150 and 210 minutes) a high fat test meal consisting of four eggs, five tablespoons of coconut oil and 1/2 a stick of butter. The peak value of 111 mg/dl occurred at 150 minutes.</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Allergies and hives</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">One of the clearest benefits I noticed
when I started eating a very low carbohydrate diet was a sharp
reduction in my seasonal allergies. On the very high carbohydrate
intervention diet, my spring allergies returned. In addition, over
the first 3 weeks of the diet, I started getting hives. The hives
went away after the first three weeks, and so have the allergies. The allergies returned during the fall allergy season (October).</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Uric acid</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">One unexpected benefit of the very high
carbohydrate diet was a reduction in serum uric acid, from a slightly
high 8.3 mg/dl on 4/3/2012 to 6.8 on 5/31/2013. I have not
investigated the likely cause or meaning of this change, but my lab
defines the reference range as 4.0-8.0 mg/dl, and elevated uric acid
levels are associated with impaired kidney function.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Homocysteine and c-reactive protein</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Initially, an increase in homocysteine
and c-reactive protein was observed (as of 5/31/2013). Elevation in
homocysteine may have been related to a deficiency in B vitamins and
supplementation was commenced (25mg B6, 2,000 mcg B12 and 1,600 mcg methyl-folate).
Elevation in c-reacitve protein is believed to be caused by a minor
viral infection at the time the May 2013 blood work was conducted.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">Homocysteine and c-reactive protein
were retested and confirmed within normal range on 8/23/2013.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Discussion</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Interventions
that make small changes to macronutrient composition may
be expected to result in small changes in blood lipids. Studies like that require statistical analysis with n>>1 to reasonably
reject the null hypothesis that a particular dietary intervention
results in no change, or no improvement, in health or biomarkers. The
present study was designed to induce a large change in blood lipids
by way of a very large change in macronutrient intake. As with all
diet studies, it necessarily involved a change in multiple dietary
factors as certain foods were reduced or eliminated (e.g. red meat),
and others were increased (e.g. fish). Therefore, it is not possible
to determine whether the effects observed were the result of changes
in macronutrient content, or of other concurrent changes.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">It
seems reasonable to assume that the effects of macronutrient changes,
if any, may not be linear. For example, it may not be possible to
infer the effects of a diet comprised of 65% carbohydrates from a
study population consuming no more than 55% carbohydrates on average.
This fact may help explain the results of the dietary intervention
studies, where the only interventions involving fat consumption below
10% of calories (the Ornish studies) were able to demonstrate
decreases in non-HDL cholesterol. In addition, studies are usually not designed to detect instances where a subset of the population shows an unusually large response to one intervention or another.</span></span></div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Contrary
to my initial assumptions, this experiment strongly supported the
hypothesis that a very high carbohydrate diet can lower non-HDL
cholesterol. In addition, it failed to support the hypotheses that
high carbohydrate diets lower HDL, raise triglycerides, cause
unhealthy blood glucose spikes and impair oral fat tolerance. Again,
it may be the case that these effects occur only in a subset of
the population, but this hypothesis has not been confirmed or refuted
because of the design of the dietary intervention studies I reviewed.</span></span></div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Fasting measurements</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">My
HDL levels on the very high carbohydrate diet were consistent with
their levels during the first few years of the low carbohydrate diet,
prior to the year of high butter consumption. However, given the
study design (n=1) and the natural variability in cholesterol levels
from day to day, this study is not powered to detect small decreases
in HDL. And why would I want to detect a very small decrease in HDL?
A small decrease most likely won't make any difference to me
personally. I had previously conducted a 4-week study of the effects
of adding sweet potatoes to a very low carbohydrate diet. I observed
a decrease in HDL during this time which was reversed once the sweet
potatoes were removed. My current results are not consistent with
that finding, or with other results (unpublished) suggesting that my
postprandial triglycerides are adversely affected by carbohydrate
consumption.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">A
number of plausible solutions to this conflict are i) certain
carbohydrates (e.g. sweet potatoes adversely affect HDL
and triglycerides, while others (e.g. white rice) do not; ii)
carbohydrates lower HDL and raise fasting triglycerides when eaten
with fat, but not in the context of a very high carbohydrate diet
where fat intake is low; iii) high fish consumption counteracts any
adverse effect on HDL and triglycerides that would otherwise have
occurred; and/or iv) as suggested by my Endocrinology and Metabolism textbook, the
several week wash-in period during which carbohydrate consumption was
gradually increased was effective in preventing these adverse
changes.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">High
carbohydrate diets are often claimed to cause deleterious changes in
LDL particle size. However, in my case, advanced lipid testing
performed on May 31, 2013 reveals favorable changes in all
lipoprotein subtractions. Total small, dense LDL particles (LDL 3 and
LDL 4 on the VAP test) decreased from 99 mg/dl on April 3, 2012 (on
the baseline low carbohydrate diet) to 37 on May 31, 2013 (8 weeks
into the very high carbohydrate diet). Larger LDL subtractions also
decreased but by a smaller absolute and relative amount (91 to 40).
Therefore, the dietary intervention has apparently caused a favorable
shift in both the ratio of large vs. small LDL particles, and also in
the absolute amount of small, dense LDL. There was also a small
decrease in VLDL, from 16 to 14 mg/dl.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">There
was also a slight favorable shift in HDL subfractions. While the
total HDL cholesterol was essentially unchanged (68 mg/dl on 4/3/2012
to 69 on 5/31/2013), the balance between large/buoyant HDL 2
(believed to be most protective) and the small/dense HDL-3 shifted
from 19/49 to 22/46. However, this change is small and it is not
clear if it has any clinical relevance.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">My
measurements of oxidized lipoproteins also contradict a common belief
in low-carbohydrate diet communities: that reduction in carbohydrate
consumption will reduce lipoprotein oxidation and therefore reduce
heart disease risk regardless in changes in total lipid levels. (See,
for example, the quote from Jefrey Gerber on page 87 of Jimmy Moore's
Cholesterol Clarity). He says that lowering carbohydrates will lower
oxidation, but my oxidized lipids decreased enormously on this diet.
In addition, while the decrease in oxidized LDL would be expected
given the large decrease in total LDL, there was also a large
decrease in oxidized HDL despite total HDL levels remaining
essentially unchanged. While the absolute level of oxidized LDL
decreased from 62 to 35, on a relative basis as a percentage of total
(direct) LDL, it increased from 33% to 45%. Oxidized HDL decreased on
a percentage basis from 53% to 28%.</span></span></div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
elevation in homocysteine suggests that the diet as implemented
provided inadequate B vitamins. Although the design of the diet
included a substantial amount of B vitamin-containing green
vegetables, the diet as implemented did not. Supplementation (25 mg
B6, 1600 mcg methyl-folate and 2000 mcg B12) rapidly reversed the
adverse change in homocysteine.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Postprandial measurements</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Because
of the human body's ability to adapt to a wide variety of diets, I
had assumed at the outset that improvements in postprandial blood
sugar control may occur in response to the very high carbohydrate
diet, and that this would likely produce a normal oral glucose
tolerance test response. In fact my glucose tolerance test results on
the very high carbohydrate diet are considered to be within <a href="http://www.mayoclinic.com/health/glucose-tolerance-test/MY00145/DSECTION=results">normal standards</a>. Note that, although the 2-hour reading
(70) is lower than the fasting level, I was not at any time
symptomatic of hypoglycemia.</span></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">You
can contrast the oral glucose tolerance test result with the full day
blood sugar measurements. Even though the glucose tolerance test
involved the consumption of a much lower dose of carbohydrates (75g),
it produced a dramatically higher blood sugar excursion than the
worst case seen during a full day (500g carbohydrates). This suggests
that the oral glucose tolerance test is not representative of an
actual day of very high carbohydrate eating (though perhaps it may be
representative of junk food or soft drink consumption).</span></span></div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Some
people are afraid to eat fruit these days because of concerns about
blood sugar. My postprandial blood sugar after the oral cantaloupe
tolerance test peaked at 107, so I'll say with confidence that I am
not likely to run my blood sugar up to unhealthy levels while eating
real foods. Note that the protein consumed along with the cantaloupe
likely triggered an insulin response that could have reduced the peak blood sugar level.</span></span></div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td><a href="http://1.bp.blogspot.com/-SKTOhOYN3F8/Un7lBc8ndcI/AAAAAAAAATE/2UF_Pjqyosc/s1600/photo.JPG" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="150" src="http://1.bp.blogspot.com/-SKTOhOYN3F8/Un7lBc8ndcI/AAAAAAAAATE/2UF_Pjqyosc/s200/photo.JPG" width="200" /></a><a href="http://4.bp.blogspot.com/-RiLNDRceFM4/Uj4WJNxMisI/AAAAAAAAASA/Uv12n0k9wRw/s1600/octt.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Times, Times New Roman, serif;"><img border="0" height="150" src="http://4.bp.blogspot.com/-RiLNDRceFM4/Uj4WJNxMisI/AAAAAAAAASA/Uv12n0k9wRw/s200/octt.jpg" width="200" /></span></a></td></tr>
<tr><td class="tr-caption"><span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Left: the aftermath of a standardized 9” oral cantaloupe tolerance test. My peak blood sugar of 107 is shown on the glucometer. The cantaloupe was very ripe and delicious.</span></span><br />
<span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="font-size: small; text-align: -webkit-auto;"><span style="font-family: Times, Times New Roman, serif;">Right: 75 grams of glucose. Yikes!</span></span></td></tr>
</tbody></table>
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<br />
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;"><br /></span></span>
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">Eating a very high carbohydrate diet might be expected to lower your
postprandial response to </span></span><span style="font-family: Times, 'Times New Roman', serif;">carbohydrates. However, it might also be
expected to worsen your postprandial response to fats, because a very
high carbohydrate diet is necessarily very low in fat.</span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">On
the very low carbohydrate diet, my peak triglycerides after a typical breakfast (described above) would occur around 3.5 hours
after the meal and would usually reach approximately 155 mg/dl. On
some days, particularly if I had done some extremely heavy exercise
the day before, my peak triglycerides would reach only 100 mg/dl.</span></span></div>
<br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">On
the very high carbohydrate diet, my triglycerides after this test
meal stayed admirably low (111 mg/dl). Although it is impossible to draw firm
conclusions from a single test (since peak postprandial triglyceride
levels can vary significantly from day to day and the reasons for
this variability are not entirely clear), this is nevertheless a
surprising result. Based on my <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">prior research</a>, I was expecting my oral fat tolerance to be impaired on
the very high carbohydrate diet, and that this would be evidenced by
a higher and possible also a later peak reading. If anything, this
result suggests an improvement in oral fat tolerance. The results,
taken together, therefore suggests a true improvement in metabolism
with no observable metabolic downsides.</span></span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Odds and ends</span></h3>
</div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The
return of my allergies on the very high carbohydrate diet was not
entirely unexpected, because I had suffered from seasonal allergies
fer years prior to adopting the low carbohydrate diet. They ended
after a few weeks, which may have been due to the end of allergy
season, or possibly because of a <a href="http://www.vitacost.com/solaray-mega-quercetin?csrc=GPF-PA-076280446869&ci_gpa=pla&ci_kw=&ci_src=17588969&ci_sku=076280446869&ci_src=17588969&ci_sku=076280446869&gclid=COvZmsub1boCFdJZ7Aod_XEAgQ">quercetin/bromelain</a> supplement
suggested by my doctor. My typical October seasonal allergies also
returned, and also may have responded to the same supplement. At this
point it is impossible for me to separate the effects of the
supplement from the end of each allergy season. The hives were
unexpected, but temporary and I have no reason to think they will
come back.</span><br />
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br />
</span></div>
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">One
of my concerns in transitioning to a very high carbohydrate diet was
with my teeth. However, I have not noticed any increase in root
sensitivity or other adverse dental health effects.</span></span></div>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Competing financial interest disclosure</span></h3>
</div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;"><br /></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: Times, Times New Roman, serif;">The author does not declare any
competing financial interests. The author also declares affirmatively
that he <u>has</u> no competing financial interests related to this
research that an ethical person would feel ethically obligated to
declare.</span><br />
<span style="font-family: Times, 'Times New Roman', serif;"><br /></span>
<br />
<h3>
<span style="font-family: Times, 'Times New Roman', serif;">Conclusions</span></h3>
</div>
<div style="margin-bottom: 0in;">
<br />
<div style="margin-bottom: 0in;">
<span style="color: black;"><span style="font-family: Times, Times New Roman, serif;">The
present study demonstrated a dramatic reduction in non-HDL
cholesterol in a short period of time in connection with the adoption
of a very high carbohydrate, non-vegetarian diet. Improvements were
also seen in oxidized lipoproteins, uric acid, and postprandial fat
and carbohydrate metabolism. Seasonal allergies, which were
virtually eliminated on the very low carbohydrate diet, returned upon
adoption of the very high carbohydrate diet. No other
deleterious effects were observed other than an increase in
homocysteine which was reversed through B-vitamin
supplementation, suggesting the diet as implemented provides
inadequate B vitamins. The diet is inexpensive and sustainable,
though long-term effects (post 7-months) are not yet known.</span></span></div>
</div>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com18tag:blogger.com,1999:blog-2658003869927046449.post-64356050354765290812013-07-20T17:06:00.002-04:002013-07-20T17:06:47.630-04:00Apricot-braised TroutIn honor of apricot season, here is something you might want to do with a bunch of extra apricots -- braise fish in them! Trout is not the mildest of fish, but the other flavors in this dish, particularly the cloves and braised apricots, combine to impart an almost meaty quality. The spices add body and complexity to the sauce. A lesser fish might be lost in the fray.<div>
<br /></div>
<div>
I had leftover fresh baby fennel from the weekend that I wanted to use, but I'm on the fence about it here and I think the dish might work just fine without it. Don't get me wrong -- it was very good, but I wouldn't have fresh baby fennel air-dropped from Lebanon just so you can make this.</div>
<div>
<br /></div>
<div>
The fish are braised whole. However, you should consider removing the bones and spine while they are raw, as the braised meat is very soft and more difficult to separate from the bones than a roasted fish would be. Please save the bones (and heads) to make stock (or send them to me -- I have an idea for an improved <a href="https://twitter.com/KMegafauna/status/354057140413034496">fish popsicle</a>).<br /><br />For cookware all you will need is a skillet with a reasonably well-fitting cover for your preferred braising method. I like to braise on an <a href="http://www.webstaurantstore.com/avantco-ic1800-countertop-induction-range-cooker-120v-1800-watt/177IC1800%20%20%20120.html">induction cooker</a>, which won't heat up your kitchen in the summer as much as an oven or gas burner.<br /><br /><h3>
Kneeless Apricot-braised Brook Trout</h3>
<br />Ingredients:<br /><ul>
<li>two brook trout (approximately 1 pound each), whole, cleaned and scaled</li>
<li>flesh from four or five apricots, cut into wedges</li>
<li>one stalk of fresh baby fennel (use the white portion, compost the greens)</li>
<li>onions</li>
<li>1-2 tsp salt and ground pepper to taste</li>
<li>5 whole cloves</li>
<li>2 pats of butter (1/4 stick)</li>
</ul>
Spice mix:<br /><ul>
<li>1/2 tsp ground cumin</li>
<li>1/2 tsp ground coriander</li>
<li>pinch of ground cayenne pepper</li>
</ul>
<div>
Steps:</div>
<ol>
<li>in a skillet, sauté onion and cloves in butter until the onions brown slightly</li>
<li>add fennel and sauté until soft</li>
<li>add spice mix and continue to sauté. Spices will darken slightly and start to form a paste</li>
<li>add apricots and trout, salt to taste, and grind black pepper on top</li>
<li>add 1/4 to 1/2 cup of water (some more will come out of the apricots), cover, and braise on low heat until fish is cooked through (30 minutes should do it but don't worry if you go a bit over)</li>
</ol>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-noVxNCuz2P4/Uer3BsxQ5EI/AAAAAAAAAPg/c51HkpCM64c/s1600/_P1A3217.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto; text-align: center;"><img border="0" height="265" src="http://3.bp.blogspot.com/-noVxNCuz2P4/Uer3BsxQ5EI/AAAAAAAAAPg/c51HkpCM64c/s400/_P1A3217.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Kneeless Apricot-braised Trout</td></tr>
</tbody></table>
<br />I consulted professional wine consultant <a href="https://twitter.com/shanareade">Shana Reade</a> and she provided the following suggestions.<br /><blockquote>
<br />My first inclination would be to suggest a Alsatian Gewürztraminer. They are typically fruity, floral, and a bit spicy. I always taste clove in the good ones, so that would pick up that note in the fish nicely. It's also a bit of a heftier wine, so wouldn't be overwhelmed by the richness of the trout. Sidebar: this wine might be the flavor you are looking for in the <a href="https://twitter.com/KMegafauna/status/354052288651866114">cod pops</a> instead of using dextrose. I will see if I have a bottle laying around the office. </blockquote>
<blockquote>
Some people are put off by any sort of residual sugar (when fermentation is stopped prior to the yeast consuming all the sugar in the grapes, so there will be more sweetness) in a wine, and Alsatian Gewürz's might have a touch in addition to already having lush tropical fruit flavors, so the dry wine fans might like a Chenin Blanc from the Loire. The two main appellations are Savennieres or Vouvray. Both would work, but Vouvray is made with varied levels of residual sugar, and they are really bad about telling people that on the label, so I think a Savennieres is the way to go, and it's awesome. It's usually a bit funky and yeasty, but mineral driven with touches of honey, and sometimes tastes a bit like wool or lanolin, but in a good way?<br /> <br />Now when you said esoteric, <a href="http://www.movia.si/en/wine/rebula">this wine</a> came to mind (Movia Rebula). I don't think the description gives justice to how neat this wine is. It's almost an orange tinge, and seems racy and rich at the same time, and kind of like drinking a bouquet of dried flowers.</blockquote>
<blockquote>
And even though this is probably going on far longer than you anticipated, for the red fans, I think a Beaujolais cru would be perfect. Beaujolais got a bad reputation for their Beaujolais nouveau, which uses a type of fermentation that produces a wine that tastes like bubble gum and banana bread. But there are 10 little villages, or crus, that make a lighter style red, with a firm but not aggressive structure, typically with a nice balance of fruit and earthiness.</blockquote>
</div>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com0tag:blogger.com,1999:blog-2658003869927046449.post-42899320755695288072013-04-15T10:00:00.000-04:002013-04-17T22:02:36.664-04:00How I fell down a murine rabbit hole<span style="font-size: small;">This post is about animal models and postprandial elephants.</span><br />
<span style="font-size: small;"><br /></span>
<br />
<h3>
<span style="font-size: small;">Personal update</span></h3>
<br />
Before I get started on today's topic, I wanted to introduce my latest experiment. Although butter had a <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">temporary beneficial effect</a> on my cholesterol levels, the benefit <a href="http://kneelessmegafauna.blogspot.com/2012/07/butter-not-like-statin-after-all.html">did not persist</a>. In fact, towards the end of last year, while my HDL levels remained quite high, the non-HDL crept up into territory I was not comfortable with. I can't say if this was due to the butter, a year of relatively high egg consumption (3/day), a longer term effect of high red meat consumption, or the consequence of several years on a low carbohydrate diet. Whatever the cause, I decided, since I've never done it before, to try out an actual high carbohydrate diet that is low in fat and cholesterol. At least at the end of this experiment I'll be able to speak about high carbohydrate diets from a position of personal experience.<br />
<br />
I ramped up my carbohydrate consumption gradually over a couple of weeks, and then abruptly switched out all the butter, eggs and red meat for about a pound each of white rice, bananas, fish, and the occasional mound of white potatoes. I sprinkle in a sprinkling of almonds, salad greens, carrots, spinach, shellfish, yogurt, and whatever else I feel like eating to round out my micronutrient requirements, which I roughly confirm from the <a href="http://ndb.nal.usda.gov/ndb/foods/show/7742">USDA data</a>. Wheat is still out, as are the vegetable oils and all processed foods.<br />
<br />
It is too early to report much in the way of results, but in the first two weeks my HDL has dropped a little, my fasting triglycerides stayed under 70, and my non-HDL has dropped about 120 points. What is also a bit of a surprise is that my blood sugar has been quite consistent and low, almost always peaking below 125 even following heroic quantities of white rice. One benefit of rice in regard to blood sugar is that I find it difficult to eat it quickly (compared to, say, a banana or sugar water). Anyway the new diet seems to agree with me so far at this very preliminary stage. In a few weeks I will feel more qualified to comment on high carbohydrate diets, having actually tried it for the first time in my life.<br />
<br />
<h3>
<span style="font-size: small;">"Totally Misleading"</span></h3>
<br />
Now on to the meat of this post. <a href="http://www.microbeworld.org/podcasts/this-week-in-microbiology/archives/1365-twim-52-clinical-microbiology-with-ellen-jo-baron">Episode 52</a> of "This Week in Microbiology" featured a conversation with clinical microbiologist Ellen Jo Baron. Although it is not the focus of the episode, she briefly told the story of how difficult it was to publish her PHD thesis on salmonella. She says:<br />
<br />
<blockquote class="tr_bq">
"What we did was compared in vitro neutrophil activity of mouse neutrophils against the mouse typhoid organism salmonella typhimurium, and then human neutrophil activity against the human typhoid agent salmonella typhi, and my work showed that they were radically different early responses, and nobody wanted to buy that because many of the premier researchers in the field had been using the mouse model of typhoid looking at vaccines et. cetera and I was showing them that it was an inappropriate model."</blockquote>
<br />
In other words, the mouse immune system behaved differently from the human immune system in what was supposed to be an animal model of a human condition. Established scientists did not like the finding and resisted its publication. However, This took place in the depths of time (the 1970s), so perhaps we can forgive our primitive forbears for their unfounded prejudices.<br />
<br />
Or maybe not? Recently in the New York Times, <span style="line-height: 19px;">Gina Kolata describes a <a href="http://www.nytimes.com/2013/02/12/science/testing-of-some-deadly-diseases-on-mice-mislead-report-says.html?_r=0">similar episode</a> in the life of a paper published by <a href="http://www.pnas.org/content/early/2013/02/07/1222878110.full.pdf">Seok et. al.</a> this February in the <a href="http://www.pnas.org/">Proceedings of the National Academy of Sciences</a></span>.<br />
<div>
<br /></div>
Like Baron, Seok et. al. were studying the behavior of immune cells under an assortment of inflammatory conditions (namely sepsis, burns and blunt trauma). The new paper recorded patterns of gene expression in human white blood cells taken from real patients. According to the the Times, the researchers ran into trouble getting their <span style="line-height: 19px;">results</span> published because they had not demonstrated that their results were consistent with the established animal models for these conditions. So they ran the experiments again with mouse cells, and, lo, they did not match at all. This, apparently, did not <span style="line-height: 19px;">comfort</span> the paper's critics. Only by submitting to <a href="http://www.pnas.org/">PNAS</a> (along with a recommendation that specific reviewers be consulted) was the team able to win publication.<br />
<div>
<br />
So back to the results: after an infection, burn, or <span style="line-height: 19px;">getting</span> <span style="line-height: 19px;">traumatized by</span> <span style="line-height: 19px;">a blunt instrument, a wide range of changes occur over time in gene expression in white blood cells, as they participate in the immune/healing response. Expression of some genes will increase while expression of others will </span><span style="line-height: 19px;">decrease. As between human cells and the corresponding mouse model, </span><span style="line-height: 19px;">correlations (r-squared) max out at 8% in the directionality of gene expression. </span>In other words, if a gene was upregulated in humans, it was essentially random whether it would be unregulated or downregulated in the corresponding mouse model. Just about half the time, the same gene, coding the same protein, under what is supposed to be the same stimulus, does the opposite thing.<br />
<br />
Interestingly, while gene expression patterns in the three human conditions were quite similar to <span style="line-height: 19px;">one another</span>, the three mouse models were very different not only from the human conditions but also from each other. So the human inflammatory response is <a href="http://everything2.com/title/Solving+mazes+of+twisty+little+passages%252C+alike+or+different">a maze of twisty passages, all alike</a>, while the mouse inflammatory response is a maze of twisty passages, all different (and all different from the human twisty passages). In addition to the directional differences in gene expression, the researchers also observed enormous differences in timing. For example, a response that lasted 4 days in <span style="line-height: 19px;">the</span> mouse might persist for 6 months in people. Yikes!<br />
<br />
These results led Gina Kolata of the Times to say that the mouse models for these conditions were "totally misleading." Seok et al, introduce their paper by pointing out that "there have been nearly 150 clinical trials testing candidate agents intended to block the inflammatory response in critically ill patients, and every one of these trials failed" (Seok page 1). (these words were too strong even for the Times -- they changed "every one" to "most"). This paper is very clearly written and I can't really sum it up better than they do:<br />
<br />
<blockquote class="tr_bq">
"here, we show that, although acute inflammatory stresses from different etiologies result in highly similar genomic responses in humans, the responses in corresponding mouse models correlate poorly with the human conditions and also, one another. Among genes changed significantly in humans, the murine orthologs are close to random in matching their human counterparts."</blockquote>
<br />
So another strike against the mouse as being the perfect biochemical equivalent to a human.<br />
<br />
Meanwhile it has been known for many years that mice respond very differently than humans to bacterial lipopolysaccharide (LPS). Also known as endotoxin, LPS has made a number of prior appearances on this blog. The hapless human is about 100,000 times more sensitive to LPS than the mouse. In 2010, Robert Munford published "<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2798013/pdf/nihms155001.pdf">Murine response to endotoxin: another dirty little secret?</a>", citing work by H. Shaw Warren, the second author on the Seok et. al. paper. So the new gene expression results add to an existing body of evidence casting doubt on the presumed similarities of human and murine immune systems.<br />
<br />
I guess, after all, rodents and humans are not so much alike. For reference, here's a recent mammalian family tree showing the distance between humans and rodents. (<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317156/">McCormack et al Genome Research 2012</a>).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-po3C6ArRwwo/UWivBO1S6xI/AAAAAAAAAMg/RcX14y3Pru0/s1600/mammal-tree.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-po3C6ArRwwo/UWivBO1S6xI/AAAAAAAAAMg/RcX14y3Pru0/s1600/mammal-tree.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: xx-small; text-align: -webkit-auto;">J. Craig Venter gets to appear personally on phylogenetic trees like this one.</span></td></tr>
</tbody></table>
<br />
The differences in gene expression between animals and humans in response to lipopolysaccharide and inflammation in general, from the 10^6 difference in sensitivity, time course differences of several orders of magnitude, and essentially zero correlation even in directionality, cast significant doubt on my earlier thoughts about lipopolysaccharide and postprandial triglycerides. As I read studies on this topic, I am constantly finding myself disappointed to pull up references only to find animal research. This is not always disclosed in the title of the paper, or even in the abstract! In my darkest hours I sometimes find myself pointing this out to people <a href="https://twitter.com/KMegafauna/status/309404700590108672">on twitter</a> (by the way, if I can fit "in mice" in a 140 character tweet, you can fit it in the title of your peer-reviewed research paper).<br />
<br />
<h3>
Digression on (Mathematical) Models</h3>
<br />
Recently I picked up a very nice <a href="http://dev.biologists.org/content/138/24/5269.full">little text book</a> by Hugo van den Berg on mathematical modeling of biological systems. It covers some of the basic stuff that I think someone doing mathematical modeling should be expected to know. Since I have been spending more time reading a book and less time on the Internet, Google has backed down on sending me ads for modeling agencies. And all of the modeling agencies that <a href="https://twitter.com/KMegafauna/status/300966576314798082">twitter-followed me</a> have since un-followed me.<br />
<br />
Some readers may not know that the field of computational biology was founded by <a href="http://en.wikipedia.org/wiki/Alan_Turing">Alan Turing</a>, the father of computer science himself. His <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDgQFjAA&url=http%3A%2F%2Fwww.dna.caltech.edu%2Fcourses%2Fcs191%2Fpaperscs191%2Fturing.pdf&ei=LLloUeuINIy70QHLuIGICQ&usg=AFQjCNGopAGCXkZ7OBVBFLY0rIh-9O6Fhg&sig2=fxl_B8WD3nGp9lfeFxxU6Q&bvm=bv.45175338,d.dmQ">landmark 1953 paper</a> on morphogenesis is available online.<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><span style="margin-left: auto; margin-right: auto;"><a href="http://xkcd.com/793/"><img border="0" src="http://4.bp.blogspot.com/-we_i-n0WL3g/UWi5rzKXR5I/AAAAAAAAAMw/pwDstx4h-7k/s1600/xkcd-physicists.png" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><a href="http://xkcd.com/793/">xkcd #793.</a></td></tr>
</tbody></table>
<br />
<br />
If you precisely define the characteristics of an imaginary object, and then investigate the consequences of your definition, you are doing mathematics. If your imaginary object is a scientific hypothesis, say, about the interactions of an organism with its environment, then mathematics can help you to understand the consequences of your hypothesis. Given a rigorous definition, the mathematical analysis of a scientific hypothesis can help you decide whether its predictions match reality. If not, then you have made a mistake, either in your hypothesis, or in its rigorous definition. In other words, mathematics makes predictions precise and therefore testable. A mathematical hypothesis cannot make hand-wary excuses or appeals to authority to justify why the experiments are giving inconsistent results. It has no choice but to slink away, refuted (and nobody wants to associate with a refuted hypothesis, right?)<br />
<br />
Lets say, for sake of a straw-man, that your hypothesis is that <a href="http://books.google.com/books?id=Pm9ZcFYtLZ4C&pg=PA10&lpg=PA10&dq=%22carbohydrate+is+driving+insulin+is+driving+fat%22&source=bl&ots=kB8T7i3saj&sig=8y2IIeNNI586YhwZR6PGDC10ROo&hl=en&sa=X&ei=8VlrUbzeDO3j4APZ8oC4Dg&ved=0CFoQ6AEwCTgK#v=onepage&q=%22carbohydrate%20is%20driving%20insulin%20is%20driving%20fat%22&f=false">carbohydrate drives insulin, and insulin drives fat storage</a>. Your model might look something like this: the amount of carbohydrate in the diet (in grams) is proportional to the daily average insulin level. And the daily average insulin level is proportional, on average, to the net amount of fat stored per day. You can test that model against real data and see that it is wrong. So you can then make adjustments until you get a fit, or abandon the hypothesis if it turns out to be unworkable.<br />
<br />
<h3>
A celestial example</h3>
<br />
Mathematics is also useful when systems become too complex for intuitive reasoning. Systems with interacting parts reach that level of complexity much more quickly than most people would guess. Take one example from physics. Assume two stars are approaching each other in space. They are interacting gravitationally, but are far enough away from other masses that they can be approximated as an isolated system. There are three possible outcomes: (i) the stars collide, (ii) the stars approach each other and then drift apart, or (iii) the stars settle into stable elliptical orbits. No matter how you set things off, you will never observe anything else. Newton solved this problem in the 17th century and, with a bit of adjustment from Einstein's relativity, the answer is close enough that our most precise observations cannot detect any deviation.<br />
<br />
What might the stable orbits look like with <a href="http://en.wikipedia.org/wiki/Three-body_problem">three stars</a> instead of two, and how would we need to set things off in order to end up in a stable orbit? You might expect that the solution would look like a slightly more complex version of the solutions to the two star problem. In fact the addition of the third star renders the mathematics so complex that a general solution is still not known. In fact, the vast majority of initial conditions do not result in stable orbits at all. <a href="http://www.gutenberg.org/files/28233/28233-pdf.pdf">Newton presented this problem</a> in its modern form in 1687. New solutions are <a href="http://news.sciencemag.org/sciencenow/2013/03/physicists-discover-a-whopping.html?rss=1">still being discovered</a> in 2013.<br />
<br />
One solution, discovered numerically by Chris Moore in 1993, has three equal masses orbiting each other in a figure eight configuration. It has been estimated that the probability of this configuration arising in the real world is between one per galaxy and one per universe (see <a href="http://www.ams.org/notices/200105/fea-montgomery.pdf">Montgomery 2001</a> citing calculations by Douglas Heggie). This might explain why nobody has yet observed stars doing this in the wild, but doesn't quite rule out such a discovery in the future. Not very intuitive in my opinion.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-OQRtj3vjqlI/UWlWqyTuj7I/AAAAAAAAAOo/W2_CkrTE5Tk/s1600/montgomery-9-mass-orbit.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-OQRtj3vjqlI/UWlWqyTuj7I/AAAAAAAAAOo/W2_CkrTE5Tk/s1600/montgomery-9-mass-orbit.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A stable orbit with 9 masses. From <a href="http://www.ams.org/notices/200105/fea-montgomery.pdf">Montgomery 2001</a>.</td></tr>
</tbody></table>
<br />
<br />
<h3>
Update on the Postprandial Elephant</h3>
<br />
Actually this all relates to the stuff I talked about <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">in my last post</a>. I made four main points, albeit in my long-winded and incomprehensible fashion.<br />
<br />
<ol>
<li>Eating fat makes triglycerides show up in the blood.</li>
<li>Very low carbohydrate diets reduce the increase in postprandial triglycerides after a meal.</li>
<li>The shape and height of the postprandial triglyceride curve, as well as the time at which the peak occurs, reflect metabolic function and possibly inflammation.</li>
<li>Therefore: measuring triglycerides after meals may be useful while eating a low carb diet.</li>
</ol>
<br />
Point 3 is conjecture at this point: what is the shape of the triglyceride curve really telling us? Could a mathematical model help us distinguish among different theories, in order to determine which is most plausible? One theory was that lipopolysaccharide (LPS), also known as endotoxin, enters the blood stream along with fat in the meal, causing an acute inflammatory response that shows up on my <a href="http://www.cardiochek.com/index.php?option=com_content&view=article&id=95&Itemid=171">test strips</a> as elevated postprandial triglycerides.<br />
<br />
<h3>
The Core Triglyceride Model</h3>
<br />
In the process of looking into triglyceride metabolism, I <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">constructed a very simple mathematical model</a> in an attempt to simulate what might happen when lipids absorb from an idealized gut into an idealized bloodstream, and then further clear out into an idealized human body. The model is depicted below. The parameters (p and c) are not directly related to any specific biological function, so for now the model will be useful primarily for making qualitative and not quantitative assessments.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-vPrhPVu540w/UWlFuJO1O1I/AAAAAAAAANA/hLuDrImNRZg/s1600/trigs-model.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-vPrhPVu540w/UWlFuJO1O1I/AAAAAAAAANA/hLuDrImNRZg/s1600/trigs-model.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Simplified diffusion model of postprandial triglyceride metabolism.</td></tr>
</tbody></table>
<br />
<br />
In addition, as the model is concerned with postprandial dynamics, I subtracted out the steady-state term that would establish a fasting triglyceride level. Below I consider a few different adjustments to the model that could get it closer to matching real data. I will be qualitatively comparing the curves produced by the model against data from <a href="http://jn.nutrition.org/content/134/4/880.full.pdf">Sharman et. al.</a>, as I did in my last post. Here are those curves to refresh your memory.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-uQi1s00xfSE/UWlGUtjdw1I/AAAAAAAAANI/6ZhDnyP7nQY/s1600/volek-trigs.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-uQi1s00xfSE/UWlGUtjdw1I/AAAAAAAAANI/6ZhDnyP7nQY/s1600/volek-trigs.gif" /></a></td></tr>
<tr><td class="tr-caption">Data from <a href="http://jn.nutrition.org/content/134/4/880.full.pdf">Sharman et. al. 2004</a>. Postprandial triglycerides following oral fat tolerance test. Subjects consumed the baseline diet identified in the legend. </td></tr>
</tbody></table>
<br />
<h3>
Hypothesis: Altered Absorption/Clearance Rate</h3>
<br />
My mathematical model as presented in <a href="http://kneelessmegafauna.blogspot.com/2013/01/the-postprandial-elephant.html">The Postprandial Elephant</a> is a diffusion model. It considers two membranes (the gut and the vascular endothelium), and models the transport of lipids across those membranes by a simplified diffusion process. This means that the rate of transport of lipids across a membrane is proportional to the concentration on the "source" side of the membrane. (For more accuracy you would use the difference between the concentrations on the two sides of the membrane, but I believe this simplification is justified.)<br />
<br />
I made one other assumption last time in order to make the math easier. That assumption, which I did not explain in my previous post, was that the absorption rate across the gut matched the clearance rate of lipids out of circulation (i.e. <i>p=c</i> in the model equations shown in the diagram above). Lets explore what happens when we eliminate this simplification and vary the two parameters against each other.<br />
<br />
In order to get a higher peak triglyceride level, as observed in metabolically unhealthy individuals, we could raise the absorption factor <i>p</i> (think of this as a "leaky gut"). Or we could reduce the clearance rate <i>c</i> (e.g. via "insulin resistance"). So lets see what happens, using jSim to produce numerical solutions. (FYI I am now using <a href="http://www.physiome.org/jsim/">jSim</a> for this stuff, which I find works much better than the OpenCell software I was using before).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-c2xE9LE_js8/UWlGnIbdbSI/AAAAAAAAANQ/m9_6BKqd8I8/s1600/absclear.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-c2xE9LE_js8/UWlGnIbdbSI/AAAAAAAAANQ/m9_6BKqd8I8/s1600/absclear.png" /></a></td></tr>
<tr><td class="tr-caption">Simplified triglyceride model with balanced absorption and clearance (black), fast absorption (red) and slow clearance (blue). Numerical simulations with <a href="http://physiome.org/jsim">jSim</a>. Plot made with <a href="http://r-project.org/">R</a>.</td></tr>
</tbody></table>
<br />
Note first of all that the fast absorption curve shows an earlier peak, as well as a steeper initial rise. This is not consistent with the abnormal metabolism cases, which show a delayed peak. In fact, the delayed peak, in my view, appears to be one of the hallmarks of impaired metabolic function. While it is still possible that accelerated fat absorption has some relevance to abnormal metabolism, we need to reject the hypothesis that it is the primarily driver for the observed impairments.<br />
<br />
The slow clearance theory looks better. The peak is both higher and later in time, as you might expect for a circumstance where lipids are being digested at the normal rate, but cleared more slowly than they should. However: note two attributes of the curve do not seem to match the data. First, the initial rise in triglycerides (the slope in the 0-2 hour range) is steeper than the baseline curve. The data appears to show a slower initial rise. Slower clearance, holding absorption rate constant, will always result in a steeper initial slope.<br />
<br />
Second, look at what happens off to the right hand side. We see in this simulation, representing a clearance rate of 1/2 the balanced case, the triglyceride levels remain significantly elevated all the way out to the right hand side of the graph, more than 10 hours after the meal. The real curves look much more symmetrical. In fact, again you can see how lowering the clearance rate while holding absorption rate constant will always result in a right-hand slope that is less steep than the left hand slope. So I think it seems fair to reject this model as well, at least as a primary driver of the phenomenon.<br />
<br />
Now I believe it has been shown that impaired metabolic states are associated with decreased triglyceride clearance. This may also be part of the explanation for why fasting triglycerides are elevated in those states. However, I think, based on the above, that there is more to the picture.<br />
<br />
<h3>
Hypothesis: Enzyme Limiting</h3>
<br />
Apparently (per Hugo van den Berg), a common trick in modeling biological systems is to assume that one process or another may be limited by the availability of a necessary enzyme.<br />
<br />
For this next experiment, we will assume that the rate at which fat is absorbed from the gut remains constant, but that clearance of triglycerides out of circulation is limited by an enzyme. It doesn't matter which enzyme. The key here is that enzyme limited processes produce curves with a certain characteristic shape, where a linear enzyme-limited regime gives way more or less quickly to an exponential decay at lower levels of the state variable. This exponential regime will look just like the simplified diffusion model discussed above.<br />
<br />
If you are a biochem fan, then you can pretend, for example, that triglyceride clearance is mediated by targeted cell surface receptors that recognize apo-lipoproteins on chylomicrons, VLDLs etc, and that the availability of these enzymes and/or the appropriate apolipoproteins themselves is a limiting factor in the rate of triglyceride clearance. Or that the availability of lipoprotein lipase is a rate-limiting step. Either way, from a statistical mechanics perspective, the absorption rate will be proportional not only to the density of triglycerides in circulation, but also to the probability of a triglyceride or lipoprotein randomly bumping into the appropriate enzyme. Hugo van den Berg goes through the derivation, and you end up with an equation of this form:<br />
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-WZXgGJQdCDU/UWlIU5vdlRI/AAAAAAAAANg/b_psYZcYmAA/s1600/eqn-enzyme-limiting.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-WZXgGJQdCDU/UWlIU5vdlRI/AAAAAAAAANg/b_psYZcYmAA/s1600/eqn-enzyme-limiting.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">State equation for an enzyme limited process.</td></tr>
</tbody></table>
<br />
<br />
Since we now have an enzyme limited process that depends on the concentration of fat in circulation, we ought to add a constant "source" term representing the body's own production of triglycerides in the fasted state. The source term will determine fasting triglyceride levels in this model. Then we add our original absorption term accounting for the lipids coming in to circulation from the gut, at a rate proportional to the intestinal fat concentration L. This gives us the following full state equation for triglycerides in circulation:<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-lYf3u8F-YpA/UWlIU1-4MRI/AAAAAAAAANc/gjqKQX67kmU/s1600/eqn-model-with-enzyme-limiting.png" imageanchor="1" style="margin-left: auto; margin-right: auto; text-align: center;"><img border="0" src="http://1.bp.blogspot.com/-lYf3u8F-YpA/UWlIU1-4MRI/AAAAAAAAANc/gjqKQX67kmU/s1600/eqn-model-with-enzyme-limiting.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fat clearance with a constant source term, gut absorption by diffusion, and enzyme limited clearance.</td></tr>
</tbody></table>
<br />
<br />
As you can see from the figure below, in the simplest enzyme limiting case, we have a steeper initial rise, and a less steep right-hand curve. The linear character of enzyme-limited triglyceride clearance is clearly visible on the right hand side of the curve, as the drop-off in the 6+ hour range looks like a straight line. Enzyme limiting is strong enough with these parameter values that we don't even see the exponential transition. The "balanced" base case without enzyme limiting is also shown, for comparison. Enzyme limited processes will in general show a much longer decay time than simple diffusion models, which exhibit only exponential decay. That said, the curve does show a higher and later peak. Working against this hypothesis is the accelerated initial rise compared to the base case, which is possibly inconsistent with the real data.<br />
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-z0XM1mENo04/UWlJt2ewnaI/AAAAAAAAAN0/cKu4hBVOauQ/s1600/enzyme-limiting-simple.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-z0XM1mENo04/UWlJt2ewnaI/AAAAAAAAAN0/cKu4hBVOauQ/s1600/enzyme-limiting-simple.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Numerical simulations with <a href="http://physiome.org/jsim">jSim</a>. Plot made with <a href="http://r-project.org/">R</a>.</td></tr>
</tbody></table>
<br />
<br />
If you futz around with the parameters of the model, you can get much closer to real-looking curves (see the figure below). I haven't thoroughly investigated what the biological significance of these parameter values may be, but it is intriguing. You can still observe the linear decay characteristics, but right-hand the slope is steeper here and more consistent with the data from Sharman et. al. The initial rise is now slower than the base case. This suggests that, with these parameter values, absorption is faster in the exponential regime (at low triglyceride levels), but slower in the linear regime at high triglyceride levels. It is not clear to me biologically why the characteristic clearance rates in the two regimes would move in opposite directions, but this is something that may be observable in experiments that were carefully designed for that purpose. The mathematical modeling process could therefore inspire targeted experiments that may otherwise not seem useful, sort of like the way theory in physics inspires experiments in that field. Sadly I will probably not be the one to do those experiments.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-qGVZig5C1EQ/UWlJt0rwuaI/AAAAAAAAANw/4UKI2Mon5uI/s1600/enzyme-limiting.png" imageanchor="1" style="margin-left: auto; margin-right: auto; text-align: center;"><img border="0" src="http://4.bp.blogspot.com/-qGVZig5C1EQ/UWlJt0rwuaI/AAAAAAAAANw/4UKI2Mon5uI/s1600/enzyme-limiting.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Numerical simulations with <a href="http://physiome.org/jsim">jSim</a>. Plot made with <a href="http://r-project.org/">R</a>.</td></tr>
</tbody></table>
<br />
Note that all of these "enzyme limited" curves reflect the same rate of digestion/absorption out of the gut. No gut barriers were harmed in this virtual experiment.<br />
<br />
All told, this is a pretty decent looking curve, even if I don't understand its biological significance.<br />
In the enzyme limiting case, it is clear that the baseline (fasting) triglyceride level is relevant to postprandial behavior. One might expect the enzyme production to adjust in compensation to chronically elevated fasting triglycerides. In addition, the fasting triglycerides could now be elevated for one of three reasons: increased endogenous production, decreased passive clearance or limited enzyme availability. Ultimately, of course, if you add enough knobs and switches to the model and you can obtain any result you want. Further refinements could be motivated by more detailed biochemical understanding (preferably with biochemistry that is relevant to humans, not just animal models).<br />
<br />
<h3>
Hypothesis: Acute Inflammation</h3>
<br />
My original hunch was that inflammation had something to do with the sustained elevation in triglycerides observed in abnormal metabolic states. Under this hypothesis, the meal triggers an inflammatory response and, given a standardized type and amount of fat in the test meal, the changes in the height and timing of the peak triglyceride reading will vary because of differences in postprandial inflammation. That inflammation may be due to the introduction of LPS and other microbial components into circulation in the course of digestion and absorption of the meal.<br />
<br />
The purpose of the innate immune system is to recognize conserved molecular patterns associated with microbes (in contrast the adaptive immune system is the part that engineers targeted antibodies when a novel threat is detected). LPS is the most widely studied example of an inflammatory microbial product. It is not a single entity, however, but a family of molecules that vary widely in biological activity. <a href="https://twitter.com/KMegafauna/status/301364558554079235">Different arrangements of LPS</a> can elicit different immune responses. Some microbes change their LPS based on their growth environment (e.g. Salmonella LPS <a href="http://jb.asm.org/content/137/2/746.full.pdf">changes as a function of temperature</a>. Other pathogens have found a way to <a href="https://twitter.com/KMegafauna/status/312615495067111424">modify their LPS</a> to bypass the innate immune response, which helps them kill their hosts before the adaptive immune system can figure out how to make antibodies. So it's complicated.<br />
<br />
I played around with a mathematical model of endotoxemia, courtesy of a very nice paper by Day et. al. published in 2006 in the Journal of Theoretical Biology ("<a href="http://www.math.pitt.edu/~rubin/pub/day2006JTB.pdf">A reduced mathematical model of the acute inflammatory response II. Capturing scenarios of repeated endotoxin administration</a>"). I implemented the model in <a href="http://www.physiome.org/jsim/">jSim</a>. The Day et. al. model shows clearly how multiple doses of LPS may have non-intuitive effects: an initial dose sometimes sensitizes the virtual patient to a later dose, which produces a heightened, and sometimes lethal response to an amount that would ordinarily be tolerable. In other scenarios, an initial dose has a de-sensitizing effect. These sorts of complex interactions appear in real patients (and animal models) and can arise from the interactions between the inflammatory and anti-inflammatory components of the model.<br />
<br />
Given that these researchers are seeking to model life-threatening conditions, the model does not seem to be suitable for my purposes where very low levels of LPS are of interest. Still I think the time spent fiddling around with the model was worthwhile.<br />
<br />
By the way, it is worth noting that the behavior of this model relies on choosing appropriate values for 15 different parameters. There is a great deal of potential variability arising from what parameter values you choose. I'll look at those parameters again below.<br />
<br />
By the way, Judy Day is a mathematician, and some of her subsequent work has looked into what general characteristics need to be present in a system of differential equations in order to give rise to the tolerance phenomena such as those observed in the biology of endotoxin exposure. So immunology is inspiring novel work in pure mathematics. Cool!<br />
<br />
<h3>
Inspiration for the acute inflammation theory</h3>
<br />
This idea that fat ingestion can cause an excessive increase in triglycerides via an acute inflammatory response to LPS was inspired in part by the so-called "lipemia of sepsis," which is the observation that individuals with systemic bacterial infections show elevations in their triglyceride levels. Sepsis is a chronic, long term condition, though, and not an acute one.<br />
<br />
Sepsis with gram negative bacteria is of course associated with systemic elevations in LPS, since gram negative bacteria shed LPS when they divide. The body detects LPS via targeted receptors and responds with a cascade of inflammatory cytokines such as IL-1, TNF-alpha, and ifKB. Later, a counter-regulatory response is seen, characterized by elevated levels of cortisol and other anti-inflammatory molecules. A lot of complex biochemistry happens. Since LPS has a lipid end that is fat soluble, and since LPS is naturally present in high quantities in the gut, it is absorbed into the body whenever we eat fat. Therefore I thought something similar to the "lipemia of sepsis" might occur on a smaller/gentler scale after meals. For this to be so, the LPS introduced with a meal would have to cause an inflammatory response on the time scale necessary to induce elevated triglycerides in the 4-6 hour window.<br />
<br />
First, lets look at a couple of studies supporting the notion that inflammation might cause postprandial increases in triglycerides.<br />
<br />
An old-ish paper by Feingold and Grunfeld ("<a href="http://diabetes.diabetesjournals.org/content/41/Supplement_2/97.full.pdf">Role of Cytokines in Inducing Hyperlipidemia</a>," Diabetes 1992) discusses the relationships between the various cytokines and lipid metabolism. They reference studies showing that "acute-phase [inflammatory] proteins are increased in the circulation of individuals with diabetes in a manner similar to that seen during infections or inflammatory illnesses." However: "the doses of TNF and IL-1 that stimulate hepatic fatty acid synthesis are similar to those that produce fever" so they are likely higher than the levels that are induced after meals.<br />
<br />
Another Feingold and Grunfeld paper from 1992 (this one with lots of other authors) ("<a href="http://www.jlr.org/content/33/12/1765.full.pdf">Endotoxin rapidly induces changes in lipid metabolism that produce hypertriglyceridemia</a>", Journal of Lipid Research) found that low doses of LPS stimulate triglyceride production by the liver, while high doses inhibit clearance of triglycerides from circulation. So this suggests that it is not only the fat being absorbed that is relevant. We need to consider triglycerides produced and/or released into circulation by the body. The authors do point out, however, that "lipoprotein metabolism differs markedly in humans compared to rodents and whether the changes observed in lipid metabolism after infections or LPS in experimental animals also occur in humans is unknown." Fair enough. Surely someone has done that in the last 21 years?<br />
<br />
A bit earlier, back in 1990, Harris (of "Barcia and Harris" fame, see below) teamed up with Feingold and Grunfeld and another guy named Rapp. The title pretty much sums it up: "<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC296783/pdf/jcinvest00075-0022.pdf">Human Very Low Density Lipoproteins and Chylomicrons Can Protect against Endotoxin-induced Death in Mice</a>." There are those words "in mice" again. It's human VLDL, but it protects mice from the effects of LPS. So it makes sense that the body might make VLDLs (which show up in the blood as triglycerides) in response to LPS, as a protective measure.<br />
<br />
Last time, I mentioned in passing the 2005 paper by Barcia and Harris called "<a href="http://cid.oxfordjournals.org/content/41/Supplement_7/S498.full.pdf">Triglyceride-rich lipoproteins as agents of innate immunity</a>" (Clinical Infectious Diseases 2005). The authors make the case that lipoproteins, including the VLDLs that show up when you measure triglycerides, play a role in innate immunity. They argue that LPS in circulation will dissolve into the circulating lipoprotein particles and, therefore, an elevation in triglycerides will actually attenuate the immune response to LPS, staving off the life-threatening consequences of an overreaction by the innate immune system. If lipoproteins (including VLDLs) are protective against LPS, then, again, you might expect the liver to produce extra ones in response to LPS exposure.<br />
<br />
Ultimately Barcia and Harris admit that "most of the evidence supporting a protective role for lipoproteins against LPS has understandably been generated with animal models of infection" and that "existing [human] data are contradictory and thus inconclusive." Okay.<br />
<br />
Last on this list is a paper titled "<a href="http://diabetes.diabetesjournals.org/content/56/7/1761.full.pdf">Metabolic Endotoxemia Initiates Obesity and Insulin Resistance</a>" (Cani et. al. 2007, Diabetes). Allow me, if I may, to add the words "in Mice" to the title. These mostly French researchers found that a high fat diet increased circulating LPS in mice. In a separate experiment, LPS infusion induced insulin resistance, fatty liver, weight gain, and chronic inflammation. In mice. Finally, transgenic mice deficient in LPS receptors (<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDMQFjAA&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCD14&ei=ulNpUdyuC4it0AHMwYGwBg&usg=AFQjCNFcRM-s_HHDNVBudUYCOML_pfnR3A&sig2=E841vhGu4gcOMDp7oHoXlw&bvm=bv.45175338,d.dmQ">CD14</a> to be precise) were immune to most of the harmful effects of LPS infusion and the obesity-inducing high fat diet. Very interesting! For mice.<br />
<br />
<h3>
What do the human studies show?</h3>
<br />
First, I'm going to briefly go over Timlin and Parks ("<a href="http://ajcn.nutrition.org/content/81/1/35.full.pdf">Temporal pattern of de novo lipogenesis in the postprandial state in healthy men</a>" AJCN 2005), which I mentioned in my last post.<br />
The human liver can make fat from scratch, and does so in certain circumstances to a greater or lesser extent depending on the individual. This process, known as de novo lipogenesis (DNL), is a potential factor in elevated triglycerides. Timlin and Parks notes that studies have shown chronic consumption of high carbohydrate diets (>50% from mono- and disaccharides) is associated with increased DNL. This makes sense, in the same way that your body makes more glucose when you are eating a low carbohydrate diet. Timlin and Parks hypothesized that an acute increase in DNL would be seen after food consumption, but the magnitude was unknown (it is very nice to see the scientists admit in the paper what their original hypothesis was!). Their experiment was to feed liquid meals high in sugar to human subjects and measure DNL postprandially. They excluded individuals with diabetes or other metabolic diseases, those taking drugs that affect lipids or metabolism, and smokers. Subjects were normal to slightly overweight. The liquid test meal roughly matched the macronutrient composition of the 3-day pre-study diet, which was about 51% carbs, 34% fat, and 14% protein.<br />
<br />
Results: triglycerides peaked after the meals, with higher peaks after the second meal. What interested me in this paper originally is it showed that DNL peaks at the same time (around 4-5 hours) as the peak triglyceride levels observed in other studies of abnormal triglyceride metabolism. Some of the new fatty acids manufactured by the liver at this time could show up in circulation as VLDL particles.<br />
<br />
Timlin and Parks showed that the magnitude of DNL was very different for different people. One person's DNL peaked at 3.9% (compared to total VLDL), another's was 29.9%. This maximum value is not very high compared to the wide divergence between the peak triglycerides seen in healthy vs. unhealthy humans. I played around with the data a bit and I don't think these levels of DNL would be sufficient to explain the differences in postprandial triglycerides seen between individuals (as observed, e.g., by Sharman et. al.). It is possible that other studies on DNL might show wider divergence, for example in individuals with metabolic syndrome or diabetes, who were excluded by Timlin and Parks. I would also love to see a comparison between individuals eating a low fat vs. a very low carbohydrate diet, but I do not believe that has been done yet. Note that Timlin and Parks did not measure LPS and it is unclear what accounts for the wide divergence in DNL seen between the different study subjects.<br />
<br />
<h3>
A digression on postprandial NEFAs</h3>
<br />
In my last post I said I would look more closely to what happens to non-esterified fatty acids ("NEFA") after meals. I suspected based on a mouse study that NEFA would behave in basically the same way as triglycerides: peaking after a meal and then returning to baseline. Below is a chart showing NEFA values after a meal from a human study and a mouse study. I think the data speaks for itself: no, they are not very much alike. In every human study I have seen, NEFAs drop after meals in humans, but increase after meals in mice.<br />
<br />
The mouse data is for olive oil alone and the human data is for a "mixed meal" that includes a very small rice cake and a 10 gram piece of cheese. It is known that insulin strongly suppresses NEFA release from adipose tissue, The rice cake should have contained about 7 grams of carbohydrates. Add in probably less than 3 grams of protein for the cheese and we're not talking about a serious insulin spike here. Perhaps this is enough, or perhaps there is more to the story than insulin.<br />
<br />
This was the lowest carbohydrate content in any human study of this kind that I could find that measured postprandial NEFA. Not sure why there do not seem to be any directly comparable studies between humans and animals (e.g. a pure fat meal in humans, or a mixed meal in mice), but if you know of one, let me know!<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-7pfG10hv8Fk/UWlNh4r4MyI/AAAAAAAAAOI/aqZ-IJuuk_Q/s1600/nefa.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-7pfG10hv8Fk/UWlNh4r4MyI/AAAAAAAAAOI/aqZ-IJuuk_Q/s1600/nefa.png" /></a></td></tr>
<tr><td class="tr-caption">Postprandial NEFA levels. Data from <a href="http://atvb.ahajournals.org/content/18/10/1606.long">Agren et. al. 1998</a> (human: blue line) and <a href="http://www.jlr.org/content/40/9/1671.full.pdf">Murray et. al. 1999</a> (mouse: red line). I can't be the first person to notice this, but they are not very much alike. Plot made with <a href="http://r-project.org/">R</a>.</td></tr>
</tbody></table>
<br />
<br />
<h3>
Omega 3s and Postprandial Triglycerides</h3>
<br />
Way back in 1988, William Harris et. al. ran an interesting experiment on the effects of various background diets on postprandial triglycerides ("<a href="http://www.jlr.org/content/29/11/1451.full.pdf">Reduction of postprandial triglyceridemia in humans by dietary n-3 fatty acids</a>", Journal of Lipid Research 1988). They varied the predominant fat in the diet and then ran oral fat tolerance tests. The diets were varied by incorporating one of three fats predominant fat types: saturated fat, vegetable oil, or fish oil. (Note by the way that the saturated fat diet contained a mixture of peanut oil and cocoa butter, so I don't think it is at all representative of what would be in a healthy low carbohydrate diet. The authors meant it as a simulation of the fatty acids in a standard American diet.)<br />
<br />
This paper is great because it shows such a large effect. The intervention was quite extreme in that the fish oil diet had 24-28 grams of omega 3 fatty acids per day. This is the sort of extreme intervention you might do in a self experiment, where, lacking entirely in statistical power, you can't waste your time trying to detect a small effect.<br />
<br />
Results? The diet high in n-3 fats substantially reduced postprandial triglycerides, regardless of the composition of the test meal. Since they are hypothesized to lower inflammation, this lends some support to my inflammation theory.<br />
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-wLV_Um9Cth4/UWlNu8WNjPI/AAAAAAAAAOQ/9WkbjG2Z4NM/s1600/Harris+1988-1.tiff" imageanchor="1" style="margin-left: auto; margin-right: auto; text-align: center;"><img border="0" height="243" src="http://1.bp.blogspot.com/-wLV_Um9Cth4/UWlNu8WNjPI/AAAAAAAAAOQ/9WkbjG2Z4NM/s400/Harris+1988-1.tiff" width="400" /></a></td></tr>
<tr><td class="tr-caption"><br />Postprandial triglycerides after a test meal predominantly composed of<br />the same fat as the background diet. From <a href="http://www.jlr.org/content/29/11/1451.full.pdf">Harris et. al. 1988.</a></td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><br /><a href="http://2.bp.blogspot.com/-PnoZCpiH22w/UWlNvFE5D5I/AAAAAAAAAOY/ndL3dMUz6Ck/s1600/Harris+1988-2.tiff" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="400" src="http://2.bp.blogspot.com/-PnoZCpiH22w/UWlNvFE5D5I/AAAAAAAAAOY/ndL3dMUz6Ck/s400/Harris+1988-2.tiff" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Postprandial triglycerides after test meals containing primarily<br />
saturated fat (A) and fish oil (B). From <a href="http://www.jlr.org/content/29/11/1451.full.pdf">Harris et. al. 1988.</a></td></tr>
</tbody></table>
<br />
<br />
It is interesting to note in passing that the vegetable oil diet (comprised of a mixture of safflower oil and corn oil) is the worst of the three diets. As I mentioned, the amount of fish oil provided was extremely high -- 24-28g per day of omega-3s. With about a pound of wild salmon per day in my current diet, I'm now eating a bit more than this, so it is a reasonable amount for a diet where protein is primarily from marine sources. We are not talking about an arctic, whale-blubber diet. By the way, this paper is the reason I do not count marine fats when considering the fat content of my high-carbohydrate diet. Right now, my experimental diet contains less than 10% non-marine fat.<br />
<br />
In 2003, Yongsoon Park and William Harris published a <a href="http://www.jlr.org/content/44/3/455.full.pdf">study</a> (in the Journal of Lipid Research) demonstrating that n-3 fatty acid supplementation lowers triglycerides by accelerating their clearance from circulation, using an injected radio-labeled lipid emulsion to track clearance in the fasting and postprandial state. However, the study notes that fish oil supplements are also known to inhibit hepatic production of VLDL in the fasted state. I'm not sure if they inhibit DNL, or otherwise slow the release of VLDLs from the liver in the postprandial state.<br />
<br />
<h3>
Lipopolysaccharide and Postprandial Triglycerides</h3>
<br />
So enough about NEFA and inflammation in general. Lets look for some human LPS papers. There are a number of studies since 2007 showing that fat consumption and digestion allows LPS to absorb into circulation from the gut. I believe the first was by Clett Erridge et. al. ("<a href="http://ajcn.nutrition.org/content/86/5/1286.full">A high fat meal induces low-grade endotoxemia: evidence of a novel mechanism of postprandial inflammation</a>"). The peak circulating levels of LPS occurred very soon after the meal (approximately 30 mins) and the LPS was cleared very quickly thereafter, consistent with other studies showing the circulating half-life of LPS to be on the order of 5 minutes. The Erridge et. al. hypothesized that this short exposure was of a sufficient magnitude to induce an inflammatory response, which would evolve over the next few hours. They noted that baseline levels of the inflammatory cytokine TNF-a correlates with postprandial lipemia. In other words, background chronic inflammation was associated with a greater increase in triglycerides after meals. That said, these researchers did not observe an increase in TNF-a associated with the spike in LPS following the high-fat test meal. This is a bit anomalous as an LPS infusion would normally cause a rise in TNF-a. So it does not all quite hold together. Perhaps the time scale involved in the LPS-induced rise in TNF-a is too long and is more of a chronic, not postprandial, phenomenon. Erridge et. al. did not measure postprandial triglycerides, so we have to make inferences from these intermediate variables.<br />
<br />
<h3>
What happens if you just measure triglycerides after an LPS infusion?</h3>
<br />
I have only found one study measuring triglycerides after an LPS infusion in humans. It is 18 years old and has racked up a grand total of 7 citations (van der Poll et. al., <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC173467/pdf/633396.pdf">Effect of hypertriglyceridemia on endotoxin responsiveness in humans</a>, Infection and Immunity 1995). Not one of those studies was an attempt at replication. According to this study, an LPS infusion in humans resulted in no change in triglycerides at 2, 6 and 24 hours post-infusion. Meanwhile, the study participants experienced the clinical symptoms of endotoxemia, which is to say, fever and other generalized flu-like symptoms. Interestingly, the study also showed that, in contrast to its effects in animals, high triglycerides (induced by a lipid infusion) did not reduce a human's inflammatory response to LPS. Once again, humans and animals: different.<br />
<br />
Based on this study, I do not think it is plausible that the LPS introduced into circulation by a single high-fat meal could affect the postprandial triglyceride response to that same meal. At least until someone tries to replicate van der Poll's experiment and gets a different answer.<br />
<br />
So what about those seven studies that cited van der Poll et. al.? Two were animal studies. One was a letter to a different journal by Stephen Lowry, the senior author on van der Poll et. al. Another was a follow-up study by van der Poll that measured cytokines but not triglycerides following LPS infusion. One (<a href="http://cvi.asm.org/content/12/1/60.full.pdf">Copeland et. al. 2005</a>) exposed both mice and humans to endotoxin and measured a variety of things other than triglycerides. One (<a href="http://cmr.asm.org/content/16/3/379.full.pdf">Amersfoort et. al. 2003</a>) was a very good review of the biochemistry of sepsis and septic shock. And the last one was a not-as-thorough review published in a dentistry journal.<br />
<br />
The two papers linked above (<a href="http://cmr.asm.org/content/16/3/379.full.pdf">Amersfoort</a> and <a href="http://cvi.asm.org/content/12/1/60.full.pdf">Copeland</a>) are worth briefly discussing. <a href="http://cmr.asm.org/content/16/3/379.full.pdf">Amersfoort</a> is a very extensive review with 620 references. The van der Poll study is among the references though it is not actually cited by the text. Amersfoort says that a number of experiments have shown that infusions of lipid emulsions or lipoproteins can reduce the effects of endotoxin, but cites 5 animal studies in support. Remember van der Poll showed that this does not happen in humans. The only findings cited that are of interest to humans in this regard are two studies by <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2192853/">Pajkrt et. al.</a> showing that infusions of high-density lipoproteins actually do reduce endotoxin response in humans. Very interesting, but not directly relevant to postprandial triglycerides. However, perhaps this can help explain why high HDL levels are associated with lower inflammation. High HDL is also associated with lower triglycerides, so perhaps it is chronic, as opposed to acute, response to low levels of LPS that raises triglycerides. That is, hypothetically, high HDL, lowering response to endotoxin, could possibly improve triglyceride clearance on a chronic bases.<br />
<br />
<a href="http://cvi.asm.org/content/12/1/60.full.pdf">Copeland</a> is, in a way, a bit of a precursor to the paper that started the meat of this post (<a href="http://www.pnas.org/content/early/2013/02/07/1222878110.full.pdf">Seok et. al.</a>), and not only because it shares several authors in common (H. Shaw Warren and Steve E. Calvano, plus the same Stephen Lowry who was senior author on van der Poll et. al. back in 1995). Copeland et. al. first calibrated a dose of endotoxin in humans in order to produce a similar response as a corresponding dose in mice. They did this by matching the levels of an anti-inflammatory cytokine, IL-6, which is released after the initial inflammatory response to endotoxin. Next, they gave this matched dose to a group of humans and a group of mice and measured a variety of physiological and biochemical phenomena. Turns out the biochemical phenomena (cytokine levels) matched extremely well. The physiological parameters (blood pressure, heart rate and body temperature) were completely different. At this point, should we be surprised?<br />
<br />
So remember the Day endotoxemia model and its 15 parameters? 8 are estimated by the authors without reference to any studies. 4 are based on animal research only, and 3 are based, at least in part, on experimental data from humans. Now I don't mean to denigrate this work at all, but I think it is important to point out (in my lengthy fashion) how uncertain our biological understanding is.<br />
<br />
<h3>
To sum up</h3>
<br />
All of the work by Harris and others on omega-3 supplementation strongly supports the idea that inflammation is a factor in postprandial triglyceride abnormalities. That work does not distinguish between chronic and acute inflammation. Chronic inflammation could explain the phenomena via alterations in passive (diffusion) and enzyme-mediated triglyceride clearance rates. Acute inflammation could play a role, possibly via postprandial de-novo lipogenesis, which is elevated postprandially (see <a href="http://ajcn.nutrition.org/content/81/1/35.full.pdf">Timlin and Parks</a>).<br />
<br />
What about the higher levels of circulating LPS seen in metabolic disease? The half-life of circulating LPS is on the order of 5 minutes. Therefore, it does not seem plausible that increased absorption following meals can explain a chronic elevation in LPS, as those differences would disappear within minutes of each meal. Therefore, the elevation seems more likely to be the result of changes to the systems that regulate LPS levels. These systems are complex, as discussed by JC Marshall in his excellent paper hypothesizing that LPS may be better thought of as an exogenous hormone ("<a href="http://cid.oxfordjournals.org/content/41/Supplement_7/S470.full">Lipopolysaccharide: An endotoxin or an exogenous hormone?</a>", Clinical Infectious Diseases 2005). If, for example, elevated cortisol (which can be a counter-regulatory response to prolonged chronic inflammation) suppresses the immune functions that clear LPS, then we would see elevated LPS wherever we see elevated cortisol. This does not point to LPS or the microbiome as the "cause" of the chronic inflammation we observe.<br />
<br />
<h3>
So long and thanks for all the biochemistry.</h3>
<br />
So what happened to all of that wonderful biochemistry? If you throw away the stuff based on animal studies, my original LPS-mediated acute inflammation hypothesis pretty much falls to pieces. Now it is still possible that other acute inflammatory pathways not involving LPS could explain the increase in postprandial triglycerides, but at this point that seems no more likely than the other, more straightforward, hypotheses I outlined above. I'm guessing a combination of impaired clearance with an enzyme-limiting term can account for the bulk of the observations. This could be the result of chronic low-level inflammation. That said, it looks to me as if the basic science is not really there (in humans) for me to productively make headway on the problem.<br />
<br />
So what now? I'm going to see in a couple of weeks what the high carbohydrate diet is doing to me when I get some detailed blood work. I'm also going to look askance at animal-based biochemistry studies, and the gurus who depend too heavily on them as the basis for their health and nutrition arguments.<br />
<br /></div>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com3tag:blogger.com,1999:blog-2658003869927046449.post-25144740848298132932013-01-08T08:07:00.000-05:002013-03-28T07:31:52.975-04:00The Postprandial ElephantHello readers. Before I get started I wanted to let you know that you can follow me on Twitter <a href="http://twitter.com/KMegafauna">Twitter</a> or <a href="http://www.facebook.com/kneeless.megafauna">Facebook</a>. I'm not a heavy user of social networking sites, but I've been posting here and there with things that are too small to go on the blog. For example, I have recently been digging into the data from the National Health and Nutrition Examination Survey (<a href="http://www.cdc.gov/nchs/nhanes/nhanes2009-2010/nhanes09_10.htm">NHANES</a>), looking for associations related to salt and blood pressure (e.g. <a href="https://twitter.com/KMegafauna/status/287062692722794496/">uric acid</a> and <a href="https://twitter.com/KMegafauna/status/286843855121301505/">kidney health</a>, as I wrote about in the context of the <a href="http://kneelessmegafauna.blogspot.com/2012/10/salt-experiment-results.html">salt/blood pressure experiment</a>). Thanks to the folks at the <a href="http://www.cdc.gov/">Centers for Disease Control and Prevention</a> for making all of this great data freely available to the public.<br />
<br />
Today's topic is something that is seldom discussed when health and diet topics come up. I started working on this post about a year ago, but first wanted to work through some other ideas that I thought were important for understanding what is going on. It was hard to write and could be even harder to understand. This post covers topics from <a href="http://kneelessmegafauna.blogspot.com/search/label/modeling">computational biology</a> to <a href="http://kneelessmegafauna.blogspot.com/search/label/lipopolysaccharide">lipopolysaccharide</a> and the <a href="http://kneelessmegafauna.blogspot.com/search/label/microbiome">microbiome</a>. Basically a little bit of everything (for my present definition of "everything"). The main topic is the usefulness of measuring one's triglycerides after meals. But first a little digression on measuring things, and on measuring blood sugar in particular.<br />
<br />
<h3>
Measuring Things</h3>
<br />
Once something can be measured it becomes a target for tracking and manipulation. Conversely, things that cannot be easily measured are often overlooked. As a result it is easy to place undue importance on measurable quantities at the expense of those that are more difficult to observe.<br />
<br />
Gary Taubes mentions this idea in reference to cholesterol in Chapter 1 of <a href="http://garytaubes.com/works/books/good-calories-bad-calories/">Good Calories, Bad Calories</a>. He writes: "what kept the cholesterol hypothesis particularly viable through the prewar years was that any physician could measure cholesterol levels in human subjects." Once discovered to be easily measurable, cholesterol became a target for management, and interventions that seemed to affect cholesterol levels were suddenly of great interest in the treatment of heart disease, regardless of any known or hypothesized relationship between those interventions and heart disease itself. Total cholesterol got managed because it was routinely measured. Later, other biomarkers were identified and studied in turn, such as HDL and fasting triglycerides. More recently, measurement of specific lipoproteins and particle density subfractions has come into <a href="https://twitter.com/Drlipid">vogue</a>.<br />
<br />
<h3>
Blood Sugar</h3>
<br />
While fasting biomarkers are interesting, a lot of the action occurs in the postprandial ("after eating") state. Your doctor probably does not do any postprandial measurements unless you are pregnant or a suspected diabetic, in which case an oral glucose tolerance test may be indicated. In the low-carb and paleo worlds, the effect of a carbohydrate-containing meal on blood sugar is well known. Many folks on the curious/nerdy spectrum even own their own glucometers and test themselves from time to time after meals.<br />
<br />
Knowing a bit about your postprandial blood sugar response seems like a good idea. There is plenty of evidence that high blood sugars are a problem (see review papers <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2738809/">here</a> and <a href="http://care.diabetesjournals.org/content/13/6/610.full.pdf">here</a>). Jenny Ruhl over at <a href="http://www.phlaunt.com/diabetes/">Blood Sugar 101</a> has written extensively about this.<br />
<br />
How does blood sugar go wrong? Tolstoy said that <a href="http://en.wikipedia.org/wiki/Anna_Karenina">happy families are all alike</a>, but that each unhappy family is unhappy in its own way. Perhaps the same may be said for carbohydrate metabolism. While young healthy people seem to be able to regulate blood sugar within a narrow range at all times, including after <a href="http://www.ihop.com/">meals</a>, people in various stages of metabolic derangement exhibit different patterns of abnormal blood sugars. Sometimes they spike too high but quickly return to normal. In others, they may rise gradually and hang out at excessive levels. Other people have so-called "reactive hypoglycemia", where a high-carbohydrate meal triggers an abnormally low blood sugar a few hours later.<br />
<br />
As the patterns of metabolic disturbance differ, we should expect that there are many different underlying causes, including a variety of disease states, short term and chronic injuries, toxin exposures, and genetic polymorphisms. A metabolic maze of <a href="http://www.rickadams.org/adventure/d_hints/hint009.html">twisty passages</a>, all different. Once started, a pattern of high blood sugar could be a problem in itself, with blood sugar reaching levels toxic to organs, nerves, and other tissues.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-hdwcTj6pDU8/T8Autqg0AZI/AAAAAAAAAEY/-40RJExN4u0/s1600/bad-things-1.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-hdwcTj6pDU8/T8Autqg0AZI/AAAAAAAAAEY/-40RJExN4u0/s1600/bad-things-1.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A model of disease mediated by glucose disregulation.</td></tr>
</tbody></table>
<br />
So I put postprandial blood sugar in the category of biomarkers that are easy to measure, and therefore more likely to be managed by many health conscious folks.<br />
<br />
Many factors can affect postprandial blood sugar. These could include your glycogen status, fasted vs. fed state, proximity to exercise (e.g. post-exercise glucose uptake), rate of gastric emptying, the size and composition of the meal, carbohydrate content of the baseline diet, how fast you eat and how good your are at chewing, sleep deprivation, stress, and glycemic index.<br />
<br />
<a href="http://kneelessmegafauna.blogspot.com/2012/04/microbiome-and-insulin-sensitvity.html">Lipopolysaccharide</a> exposure can also <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2797919/pdf/zdb172.pdf">cause insulin resistance</a> and raise postprandial blood sugar. The microbiome is involved in its own complex manner, as we saw with the <a href="http://kneelessmegafauna.blogspot.com/2012/04/microbiome-and-insulin-sensitvity.html">TLR-2 knockout mice</a>. Even <a href="http://www.ncbi.nlm.nih.gov/pubmed/9187413">ambient temperature</a> may have an effect. Finally, the behavior of pancreatic beta cells is known to be quite complex and <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDoQFjAA&url=http%3A%2F%2Ffaculty.washington.edu%2Fgennari%2Fteaching%2F591-BioSimSem%2FBergman-minmodel05.pdf&ei=8eDoUITEA6i30gHv4oHIBA&usg=AFQjCNEsyxhgdu3VS1EDsF94z8dZMyAjDQ&bvm=bv.1355534169,d.dmQ">non-linear</a>, so the blood sugar response to a particular meal may be difficult to predict.<br />
<br />
<h3>
The Elephant in the Room</h3>
<br />
Carbohydrate (primarily glucose) is not the only circulating energy substrate. It is one of four main categories, the others being fat (usually packaged in triglyceride form and carried by lipoproteins), amino acids (which can be <a href="http://en.wikipedia.org/wiki/Glucogenic_amino_acid">glucogenic</a> or <a href="http://en.wikipedia.org/wiki/Ketogenic_amino_acid">ketogenic</a>), and ketones. A few other molecules such as lactate and pyruvate can also serve as circulating energy substrates. <br />
<br />
When you eat a lower carbohydrate diet, your fat intake necessarily goes up, and when you eat fat, that fat is absorbed and enters circulation in triglyceride form. So at some point I began to wonder whether eating a higher fat diet was spiking my triglycerides at the same time as it was normalizing my blood sugar. While it is well known that fasting triglycerides go down on a low carb/high fat diet (see e.g. <a href="http://ccjm.org/content/69/11/849.full.pdf">Volek and Westman 2002</a>), it was not clear to me what happens to triglycerides after a high-fat meal.<br />
<div>
<br />
<h3>
Some Fat Diabetic Rats</h3>
<br />
The figures below come from a study on diabetic rats (<a href="https://www.jstage.jst.go.jp/article/endocrj/55/2/55_K07E-124/_article">Motojima et al 2008</a>). I like it because it shows the substitution of high postprandial blood sugar on a standard high carbohydrate rat diet for high postprandial triglycerides on a high fat diet. (Note also that <a href="http://carbsanity.blogspot.com/2011/02/elevated-free-fatty-acids-detrimental.html">NEFA</a> (non-esterified fatty acids) in the lower right chart does basically the same thing that triglycerides do. We'll come back to those in a bit.) Also note that the peak in triglycerides comes a bit later than the peak in blood sugar. This is likely due to the fact that fatty acids absorb more slowly than carbohydrates. That said, the pattern is pretty much the same between fats and carbs: after a meal, circulating energy substrates peak and then go back down.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-RYtRAzUGz0Q/UOjQC2LMZfI/AAAAAAAAAKo/QDf5tDk0i0A/s1600/motojima2008-postprandial.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-RYtRAzUGz0Q/UOjQC2LMZfI/AAAAAAAAAKo/QDf5tDk0i0A/s1600/motojima2008-postprandial.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Postprandial values for standard (solid circles) and high fat (open squares) diets in Goto-Kakizaki diabetic obese rats. They had to train the rats to eat their chow during a one-hour window, twice a day, because rats would ordinarily not do that. From Motojima et al 2008.</td></tr>
</tbody></table>
<br />
One last item to note in these charts is what happens on the right hand side, long after the meal has been digested. Note that the high fat diet causes a long term elevation of not only triglycerides and NEFA, but also of insulin, compared to the standard chow. In fact, it even looks like the triglycerides creep higher from the 12:00 to the 15:00 readings. For now, let's arbitrarily label this extended post-meal phenomenon "<i>inflammation</i>."<br />
<br />
We know by the way that the high fat diets used in these sorts of studies cause metabolic problems in rats, which is why they are used as a model of obesity. We should not therefore assume, as many wrongly do, that high fat diets are also unhealthy for humans. However, we can look at this sort of animal research as a guide to what happens when a diet does induce metabolic problems in humans (elevated fasting triglycerides would be an example of that kind of diet).<br />
<br />
<div>
So while it is normal for circulating energy in the form of blood sugar and triglycerides to go up after meals, if it goes up too much or for too long you end up in a sort of metabolic <a href="https://www.youtube.com/watch?v=98AzJT8FlmY">gasoline fight</a>. Like elevated blood sugar, elevated postprandial triglycerides is associated with heart disease and stroke and a host of other bad consequences. See, e.g. a recent review ("<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3141088/pdf/nihms303906.pdf">Triglycerides and Heart Disease, Still a Hypothesis?</a>", Goldberg et. al. 2011). A <a href="http://circ.ahajournals.org/content/123/20/2292.full">scientific statement</a> by the American Heart Association cites a pile of research related to this topic as well.<br />
<br />
Diabetes is a metabolic disregulation that causes excess postprandial blood sugar. It also causes excess postprandial triglycerides. For details on how this works, you can consult <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1743184/">this review</a> article (Tushuizen et. al. 2004). On the other hand, a metabolically healthy person should be able to eat reasonable amounts of a wide range of macronutrient combinations without adverse postprandial effects.</div>
</div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-T2GN72VmabQ/T8A0cqsmBYI/AAAAAAAAAEk/PMfzFYsOwWc/s1600/bad-things-2.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-T2GN72VmabQ/T8A0cqsmBYI/AAAAAAAAAEk/PMfzFYsOwWc/s1600/bad-things-2.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Expanded model: a variety of bad things can disrupt one or more regulatory systems, resulting in postprandial abnormalities in glucose and/or fat metabolism.</td></tr>
</tbody></table>
<br />
<h3>
How do Carbohydrates Affect Triglycerides?</h3>
<br />
You may have heard in low carb diet circles that it is actually carbohydrate, and not fat, that makes triglycerides go up. This is both true, misleading, and false. Let me explain.<br />
<br />
What is almost certainly true is that a high carbohydrate diet can cause fasting triglycerides to go up. This is widely understood to be the case, and was noted by the <a href="http://content.karger.com/produktedb/produkte.asp?DOI=000335326&typ=pdf">German dieticians</a> in the guidelines I linked to in my writeup on<a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html"> carbohydrates and HDL</a>. In fact, HDL and triglyceride levels are tightly interconnected, and it seems to be the case that most things that raise HDL will also lower triglycerides. This probably has something to do with the action of <a href="http://en.wikipedia.org/wiki/Cholesterylester_transfer_protein">cholesterylester transfer protein</a>, but my head hurts every time I try to figure it out.<br />
<br />
What about postprandial triglycerides? Well, ingestion of a sufficient amount of fat causes an acute rise in triglycerides, generally peaking between 2 and 6 hours. This fact is very well known in the medical community and has been known for a very long time. See e.g. this description of an oral fat tolerance test given to dogs by <a href="http://www.jbc.org/content/32/3/337.full.pdf">Arthur Knudson 1917</a>. He fed fat to dogs and then watched the fat in their blood go up as they digested it. The protocol they used was also commonly used on humans and is remarkably similar to the methods used in modern studies investigating the same phenomena.<br />
<br />
Absorption of fat is also associated with an acute phase inflammatory response. Lipopolysaccharide ("LPS") is involved, as discovered by Clett Erridge et. al. in 2007 ("<a href="http://ajcn.nutrition.org/content/86/5/1286.full">A high fat meal induces low-grade endotoxemia: evidence of a novel mechanism of postprandial inflammation</a>"). Postprandial increases in triglycerides have been found to be correlated with LPS in obese subjects (see <a href="http://www.jlr.org/content/53/5/973.abstract">Clemente-Postigo 2012</a>). So the question is not whether fat consumption raises triglycerides. The question is how high does it raise them and how long does it raise them for?<br />
<br />
A study from Jeff Volek's lab (<a href="http://jn.nutrition.org/content/134/4/880.full">Sharman et. al. 2004</a>) showed that consumption of a very low carbohydrate diet can significantly reduce postprandial triglycerides in response to a high fat test meal. The study used two six-week dietary interventions (low carb and low fat) in a crossover design. The low carbohydrate diet contained approximately 10% carbohydrate. Analysis based on diet records confirmed that the participants were eating only 36 grams of carbohydrate per day on average. So in contrast to many other low carbohydrate diet studies, this one really used a low carbohydrate diet, for a sufficient duration to allow the initial phases of fat adaptation to take place.<br />
<br />
Note that both diets were hypocaloric. As these were overweight individuals, we might expect metabolic health to improve on any reasonably dietary intervention of this duration that is low in calories.<br />
<br />
At baseline and after the end of each six week intervention period, each participant was given an oral fat tolerance test consisting of a standardized high-fat test meal (the same idea as what Arthur Knudson did to his dogs in 1917). Serum triglycerides were measured hourly following the test and the results are shown below.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-j2YYy6ItTAg/T8F6gkNwUBI/AAAAAAAAAE8/EVAsgBop6m8/s1600/volek-trigs.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-j2YYy6ItTAg/T8F6gkNwUBI/AAAAAAAAAE8/EVAsgBop6m8/s1600/volek-trigs.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Triglycerides after high-fat test meal. Sharman et. al. 2004.</td></tr>
</tbody></table>
<br />
The first thing to note is that these were metabolically unhealthy individuals. The dotted curve shows the baseline result after the subjects had been consuming their normal diets. Note that the peak occurs at 4 hours and is very high (multiply mmol/L by 88.5 to get mg/dL, the peak looks to be approximately 290 mg/dL).<br />
<br />
Second, note that both diets improved matters significantly compared to baseline in these overweight men. Both diets reduced fasting triglycerides (the "pre" point), and the low carbohydrate diet reduced them more as you would expect. The low carbohydrate group also has a much greater improvement in postprandial numbers, both in the height of the peak (it looks to be about 185 mg/dL), but also in its earlier time of occurrence. The total "area under the curve" is of course much lower in the low carbohydrate group compared to the low fat group or the baseline diet. The long tail of elevated triglycerides in the baseline and low fat groups is reminiscent of what I arbitrarily decided to call "inflammation" when we saw it in the obese diabetic rats. For the time being lets call it "inflammation" here too.<br />
<br />
Now take a look at the points at 6-hour mark. This is where a person might typically be starting their next meal. If triglycerides are still high here from the last meal, the next meal will pile on top and drive them even higher. The triglyceride level for the low fat group at 6 hours is about where the peak triglycerides were in the low carb group at hour 3. The triglycerides for the low carb group on the other hand have dropped to about where they were when the low fat dieters were in the fasted state. A second high-fat meal at this stage would be much worse for the low fat dieters than for the low carb dieters.<br />
<br />
Of course, typically the low fat dieters would not be having a fatty meal, they'd be having a crunchy carby meal. And that brings up a sensible criticism of this work. You might naturally expect the low carb group to better tolerate a high-fat meal because of their higher baseline fat consumption, in the same way that low carb-adapted folks may not do to well in a glucose tolerance test unless they are given the opportunity to adapt to carbohydrates over a couple of days beforehand. There is probably an element of truth to this. However I would point out that a metabolically healthy individual should be able to undergo a typical oral fat tolerance test while showing results similar to what the low carb group shows here. It looks to me as if the low carb intervention resulted in a substantial correction of a metabolic abnormality.<br />
<br />
In addition, my experience testing my own triglycerides over the past year suggests that even adding a relatively small amount of carbohydrate to a high fat diet is enough to worsen postprandial triglycerides. At least this seems to be the case for me, and it would be very interesting to see if there is any research on this phenomenon. I would think the threshold would probably vary from one person to another, in the same way that people who successfully lose weight on low carbohydrate diets may have different threshold levels of carbohydrate consumption before things start to go pear shaped.<br />
<br />
<h3>
So What About That Pesky Lipopolysaccharide?</h3>
<br />
As mentioned, <a href="http://ajcn.nutrition.org/content/86/5/1286.full">Clett Erridge et. al.</a> showed that fat consumption permits lipopolysaccharide to enter the body through the gut, thereby inducing low-grade inflammation. It's a neat paper that looks at the problem from multiple angles -- worth a skim if you have time.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-D_f9WnTOagc/UOvR-aA8RmI/AAAAAAAAAMM/pzn7w_665gY/s1600/Kdo2-lipidA.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="345" src="http://2.bp.blogspot.com/-D_f9WnTOagc/UOvR-aA8RmI/AAAAAAAAAMM/pzn7w_665gY/s400/Kdo2-lipidA.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Lipopolysaccharide's infamous lipid A.</td></tr>
</tbody></table>
<br />
<br />
One might criticize Erridge's experiment by pointing out that the "high fat meal" consisted of a cup of tea and <i>three slices of buttered toast</i>. It was indeed high in fat, but you could argue, if you had PaleoTM inclinations, that it is actually the gluten in the bread and not the fat causing the gut barrier dysfunction. Gluten -> Leaky Gut -> LPS = Bad.<br />
<br />
I would point out that Erridge's experiment was carried out in the United Kingdom, and it may have been considered unacceptably rude, or even against IRB requirements, to recruit subjects for a multi-hour ordeal without offering them a <a href="http://www.nicecupofteaandasitdown.com/">nice up of tea</a> and a <a href="http://www.bbc.co.uk/news/uk-15752918">buttered toast sandwich</a>. Anyway, subsequent work (see <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858203/">Deopurkar et. al. 2010</a>) found the same effect after ingestion of dairy cream alone. I would like to see more replications of this result with different fats, but I won't hold my breath until someone tries it with a Paleo ApprovedTM wild caught grass fed organic fat source. Part of the trouble is that lipopolysaccharide is maddeningly difficult to measure, coming as it does in picogram quantities and having a potential circulating half-life measured in a few minutes.<br />
<br />
The <a href="http://jn.nutrition.org/content/134/4/880.full">2004 Sharman</a> paper from Jeff Volek's lab (in addition to my own experiences) strongly suggests that LPS is not going to be a problem on a decent high fat diet. In that study, we saw the profound anti-inflammatory effects of a few weeks of fat adaptation. I suspect that, when and if the experiment is done, researchers will discover that fat adaptation either blunts the absorption of LPS, speeds its clearance from circulation, or attenuates the body's inflammatory response to it. We won't know for sure until they do the study, so lets hope at least that someone is working on it.<br />
<br />
<h3>
What About Those Pesky NEFAs?</h3>
<br />
Evelyn has written extensively at <a href="http://carbsanity.blogspot.com/">CarbSane</a> about the potentially toxic effects of <a href="http://carbsanity.blogspot.com/2011/02/elevated-free-fatty-acids-detrimental.html">non-esterified fatty acids</a>, which increase in circulation in the postprandial state. I don't know much about those, and I will be doing some more reading to get up to speed. As we saw with the fat diabetic rat study, it may be the case that NEFAs move in concert with triglycerides, so we can measure them by proxy. In other words, it may be the case that NEFAs come out of adipose tissue at the same time, and for the same reason, as the liver is producing excess VLDL particles. I will be on the look out for studies that suggest otherwise. For the time being, I'm not going to hold my breath until someone publishes (in an open-access journal) the exact NEFA study I'd like to see.<br />
<br />
<h3>
Some Personal Observations</h3>
<br />
So the <a href="http://cardiochek.com/">CardioChek</a> meter I have can measure triglycerides. Ordinarily this feature would be used in the fasted state as part of a standard three chemistry lipid panel (with total cholesterol, HDL and fasted triglycerides). However, nobody will stop you from using the triglyceride strips after meals (I won't tell). So I ordered a box last fall to play around with. The strips showed up a week into my sweet potato experiment, which I talked about previously in "<a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html">Do Carbs Lower HDL?</a>". I was still learning how best to use them (e.g. how long after a meal I should test), but I got some interesting results. I was surprised in a couple of instances to see numbers in excess of 200 mg/dl, for example after having a rib eye steak, a salad and a cup of nuts for dinner. These days, on a lower carbohydrate diet, I seldom see a peak reading over 150 despite some rather high fat meals. For example, readings 2.5 hours after a <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">1,000 calorie omelette</a> usually range from 130 to 150 but can be much lower the day after heavy exercise. Readings at 3.5 hours are almost always lower than the 2.5 hour reading, indicating that the peak occurs before that time (the omelette contains 110 grams of fat, 75 grams of which are saturated, which is higher than the amounts used in the fat tolerance tests we've looked at).<br />
<br />
My postprandial triglycerides were generally higher during my one month "safe starch" experiment, which is entirely consistent with the significant <a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html">drop in HDL</a> that I experienced during that time. I don't measure that frequently, but my maximum triglyceride level these days usually stays under 155.<br />
<br />
<h3>
A Digression on Modeling </h3>
<br />
I've written a little bit about the idea that we can better understand complex systems by building models, and then playing around with the models to see how they behave. Of course, models are <a href="http://kneelessmegafauna.blogspot.com/2012/05/garbage-in-garbage-out-at-new-york.html">no good</a> if they don't reflect reality. On the other hand, a good model can be not only a useful clinical tool (see e.g. <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDoQFjAA&url=http%3A%2F%2Ffaculty.washington.edu%2Fgennari%2Fteaching%2F591-BioSimSem%2FBergman-minmodel05.pdf&ei=8eDoUITEA6i30gHv4oHIBA&usg=AFQjCNEsyxhgdu3VS1EDsF94z8dZMyAjDQ&bvm=bv.1355534169,d.dmQ">the minimal model of insulin</a>), but can also help bring about important discoveries (e.g. the dominance of the kidney fluid mechanism of blood pressure control using the <a href="http://kneelessmegafauna.blogspot.com/2012/09/computational-hemodynamics.html">Guyton molel</a>).<br />
<br />
So I decided to construct a simple model to see if it could help me understand the triglyceride readings I've been seeing. The model is described by the diagram below. It is the simplest thing I could come up with.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-ux_rrINvC0I/UOoU9t-McSI/AAAAAAAAALQ/D18ZH7TLSiQ/s1600/trigs-model.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-ux_rrINvC0I/UOoU9t-McSI/AAAAAAAAALQ/D18ZH7TLSiQ/s1600/trigs-model.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A simple model of triglyceride absorption and clearance.</td></tr>
</tbody></table>
<br />
The model has two compartments: the gut and the systemic circulation. The rest of the tissues in the body take up lipids from circulation, but are modeled as an infinite sink and are not separately modeled. Ingested lipids are absorbed from the gut into circulation, and then cleared from circulation into the tissues. The purpose of the model is to understand what the dynamics of that process may look like.<br />
<br />
The initial conditions are determined by the amount of lipids ingested. This quantity (L) decreases as lipids are absorbed, at a rate equal to a constant (p) representing the permeability of the gut, multiplied by the amount of lipids remaining. Mathematically, the gut compartment is described by a simple first order differential equation, <i>dL/dt = -pL</i>.<br />
<br />
Circulating lipids, represented by the variable C, increase when lipids are absorbed and decrease when they are cleared. The absorption term is the same as that for the gut compartment (pL) with the sign reversed. Intuitively, this means that every bit of lipid that leaves the gut immediately enters the circulation. The clearance of lipids from circulation is modeled by a term similar to the term describing absorption in the gut compartment. Lipids are cleared from circulation in proportion to the amount remaining in circulation, multiplied by a clearance factor (c). There is no accommodation for the metabolic state or storage capacity of the adipose or other tissues of the body. Mathematically, this gives us another first order differential equation, this time with two terms: <i>dC/dt = pL - cC</i>. In this model, the amount of fasting lipids is normalized to zero. In real life there will be a constant offset to the measured value of C.<br />
<br />
<div style="margin-bottom: 0in;">
The goal is to understand how the amount of circulating lipids changes over time. This could give some guidance in interpreting triglyceride readings taken at different times after a test meal. The model is very simple so far and does not yet take into account the mysterious elevations in triglycerides that I have so far been arbitrarily calling "inflammation." So let's look at it for now as a picture of the postprandial triglyceride curve for an idealized perfect human that has no inflammation.</div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<br /></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-b0CNjQME_uM/UOullUlKkSI/AAAAAAAAALk/J8QmfntbjQY/s1600/curve.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-b0CNjQME_uM/UOullUlKkSI/AAAAAAAAALk/J8QmfntbjQY/s1600/curve.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Triglycerides vs. time in response to a single ingested bolus, based on a simplified model.</td><td class="tr-caption" style="text-align: center;"><br /></td><td class="tr-caption" style="text-align: center;"><br /></td></tr>
</tbody></table>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
I will not delve deeply here into the mathematics behind the model. Suffice it to say that after solving the two differential equations and making a biologically plausible simplification, you get a curve of the form <style type="text/css"> <!-- @page { margin: 0.79in } P { margin-bottom: 0.08in } </style><i>C=axe<sup>-bx</sup>+k</i>. The model has three degrees of freedom, corresponding roughly to the height and width of the curve, plus a constant factor which can be calibrated to the fasting triglyceride measurement. This equation can now be taken into a statistical computing environment and tested against real data.</div>
<h3>
</h3>
<h3>
A Test of Three Foods</h3>
<br />
Here is a little bit of the data I have collected so far. The chart below shows the results of a series of test meals each containing a single food: avocados, macadamia nuts, and coconut oil (which was emulsified in warm water). In each case the meals were standardized to 75g of fat based on tables from the USDA nutrient database. Each food is predominantly fat, but the fatty acid profiles are quite different. Each food was consumed in its whole form along with its usual vitamins, minerals and other micronutrients.<br />
<br />
The tests were conducted on successive Saturday afternoons in the fasted state, during the same month when I was doing the <a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html">safe starches experiment</a> and eating 100g of extra carbs from sweet potatoes per day. The fatty acid profiles of these three test meals are very different, as was their digestibility (particularly so in the case of the coconut oil).<br />
<br />
The three foods had very different effects on my postprandial triglycerides, with avocados being the worst and coconut oil being the best. Of course the coconut oil would have produced a great deal of circulating ketones, which I did not measure. I believe the numbers below are roughly consistent with research I have seen comparing the effects different fatty acids. In addition, the data suggests that, as you might expect, the macadamia nuts were digesting slowest of all three fats.<br />
<br />
The points in the graph below are the actual measurements and the curves show the best-fit solutions to my simplified triglyceride dynamics model. The curves were fitted in <a href="http://www.r-project.org/">R</a> using <a href="http://en.wikipedia.org/wiki/Non-linear_least_squares">nonlinear least squares</a>. The fits are not perfect of course, as the model is oversimplified at present and there will always be measurement error to contend with. In the next section I will discuss a possible enhancement to the model.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-ttf91-A4HC4/UOnpp_X5sxI/AAAAAAAAAK8/NzDd-hIFbGs/s1600/foods.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-ttf91-A4HC4/UOnpp_X5sxI/AAAAAAAAAK8/NzDd-hIFbGs/s1600/foods.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Triglyceride values and fitted curves based on the idealized computational model. Green: avocado; red: macadamia nuts; brown: coconut oil. Each meal was eaten at time=0 on successive Saturday afternoons in the fasted state. Each meal standardized to 75g fat.</td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<h3>
</h3>
<h3>
Using the Model: Idealized Response Plus Inflammation?</h3>
<br />
I took a look at the data from the <a href="http://jn.nutrition.org/content/134/4/880.full">Sharman paper</a> in light of my simplified model. Since the very low carbohydrate group in the Sharman study showed the lowest fasting and peak triglycerides, as well as the fastest clearance, we can assume they suffered the lowest chronic and postprandial inflammation. Therefore it is expected that the shape of the curve for the very low carbohydrate group would most closely approximate the ideal shape predicted by the simplified model. This is indeed the case in this data set.<br />
<br />
As mentioned above, my presumption is that the idealized model will most closely reflect the dynamics of lipid absorption in a perfectly healthy, non-inflammatory state. Differences between actual data readings and the model predictions could be used to gauge the extent of both chronic and acute/postprandial inflammation. These results can be obtained with this data set by fitting the curve predicted by the model to the data points obtained from the low carbohydrate group. In this case, only the points along the rising left hand slope were used for the fit, in order to prevent the fitted curve from overshooting.<br />
<br />
The graph below on the left shows the actual data from Sharman et. al. in red (baseline), green (low fat) and blue (low carb). The black line is the fitted model prediction. The graph on the right shows the differences between the actual readings for each series and the predictions of the model fitted to the low carbohydrate points.<br />
<br />
The offset at time t=0 represents elevated fasting triglycerides, a chronic abnormality, while the differences in area under the curve, after adjusting for the baseline difference at t=0, could reflect different postprandial inflammatory responses.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-v7MZBKaxFlU/UOunS4klXGI/AAAAAAAAAL4/IH-fgQ7eqgU/s1600/trigs-sharman-fit.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-v7MZBKaxFlU/UOunS4klXGI/AAAAAAAAAL4/IH-fgQ7eqgU/s1600/trigs-sharman-fit.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Time on x axis in hours (test meal at t=1). Blue=very low carbohydrate, green=low fat, red=baseline, black=model fitted to very low carbohydrate using nonlinear least squares (nls()). Left chart shows original triglyceride measurements and model. Right chart shows original data points in each series minus model fit to the very low carbohydrate data points. Model was optimized for fit to points at t=1, 2 and 9 hours. Data from Sharman et. al. 2004. </td></tr>
</tbody></table>
<br />
The Sharman data are interesting because the three series, though quite different in appearance, were taken in the same individuals in a balanced crossover study design, and using the same standardized challenge meal. We don't need to calibrate the curves to account for changes in body size, genetics or any other factor. The only variable is the metabolic state of the individual resulting from the dietary intervention. This is why it makes sense to compare all three curves to the model prediction as fit only to the low carbohydrate data points.<br />
<br />
We see that all three curves reflect an increase in "area under the curve" as compared to the idealized model. One hypothesis is that the low fat and baseline curves are higher because of blunted absorption of fat. However, when fiddling with the idealized model, it becomes apparent that blunted absorption would result in a more skewed triglyceride curve, instead of the more symmetrical ones observed here in connection metabolic disturbance. Therefore the model suggests this hypothesis is not correct. (Note for math nerds: the approximate model solution presented in this post has only three degrees of freedom and does not exhibit this skewing behavior. You need to work with the full solution with all four degrees of freedom to see it.)<br />
<br />
The liver increases production of VLDL particles after meals (see e.g. <a href="http://ajcn.nutrition.org/content/81/1/35.full">Timlin and Parks 2005</a>), contributing to the postprandial rise in triglycerides. This production is further increased in response to inflammation (e.g. exposure to LPS -- check out this awesome paper by <a href="http://cid.oxfordjournals.org/content/41/Supplement_7/S498.full">Barcia and Harris</a> to see why that might be happening). Now take a look at the chart on the right hand side above. Note that the curves are all approximately the same shape, but differ in height. Note that they all peak around t=5 (four hours after the meal), just as Timlin and Parks say they should if they reflect hepatic VLDL production. So basically that's why I think it's inflammation.<br />
<br />
Based on the above, the constant term in the idealized model can be used to represent chronic inflammation. As before this would be calibrated to fasting triglycerides, with the caveat that they would need to be truly fasted numbers (i.e. 8-10 hour fasts may not be sufficient in individuals who present extended post-meal inflammation). In addition, a term can be added to reflect the release of VLDL triggered by the acute inflammatory response caused by test meal.<br />
<br />
<h3>
Concluding Remarks</h3>
<br />
Mainstream recommendations are that fasting triglycerides should stay below 150. Now I'm not sure a truly metabolically healthy individual will have fasting triglycerides of 150, but as a postprandial number, it seems to be a reasonable target. Based on the evidence presented above, I think a more significant factor may turn out to be the existence of an inflammatory tail, which would show up in the 4+ hour postprandial readings. However, at least as compared to blood sugar, the epidemiological evidence is quite thin, so it is hard to recommend any particular thresholds of concern.<br />
<br />
From browsing around the scientific literature and my own experience with the test strips, there appear to be a variety of things that can cause elevated postprandial triglycerides. Here are a few:<br />
<br />
<ul>
<li>Fed vs fasted state (calorie excess or deficit)</li>
<li>Exercise (beyond the effect caused by energy depletion)</li>
<li>Type of fat in the meal</li>
<li>Type of fat in baseline diet (particularly, lack of omega-3 fats)</li>
<li>Baseline carbohydrate consumption</li>
<li>Lipopolysaccharide and inflammation in general</li>
</ul>
<br />
Funny, this looks sort of like the list I laid out earlier for the factors affecting blood sugar.<br />
<br />
A 2010 article ("<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989358/">Dietary cholesterol and egg yolks: Not for patients at risk of vascular disease</a>") makes the case that eggs are a bad idea because their cholesterol content will lead to elevated postprandial triglycerides. That hasn't been my experience, but it would be pretty straightforward to test it. A test of two meals, calibrated for total fat and calories, with a non-cholesterol containing fat substituting for egg yolks in the control meal.<br />
<br />
A variety of lines of evidence suggest that the polyphenols in olive oil could inhibit postprandial inflammation. The experiment here would be to compare the triglyceride response to extra light olive oil vs. a very spicy unfiltered extra virgin. The fatty acid content should be similar but the oils would differ greatly in polyphenol content.<br />
<br />
It has been suggested that oxidative stress mediates these phenomena. A high dose of vitamin c or e, or a glutathione precursor (e.g. whey protein) may show an effect when consumed near the meal. It would be interesting to see how the triglyceride readings vary based on the timing of the antioxidant dose relative to the meal.<br />
<br />
Overall I think triglycerides are a good target for self-experimentation. They seem to provide quick insight into metabolism and inflammation that is hard to get any other way. Experiments can be done quickly instead of waiting months for fasting lipoproteins to reach homeostasis. That said, there is some inconsistency in readings, suggesting significant measurement error and perhaps a hypersensitivity to your state of health, making single readings quite difficult to interpret. Likewise, readings taken far apart in time can be very difficult to compare.<br />
<br />
In the mean time, it is interesting to see what kinds of insights we can get by building simple models of ourselves in our computers. If you'd like to try it yourself, take a look at <a href="http://www.cellml.org/">CellML</a>, an open standard for storing and sharing computational models. A free software implementation called <a href="http://www.cellml.org/tools/opencell">OpenCell</a> is available for Linux, Windows and Mac OS.<br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com2tag:blogger.com,1999:blog-2658003869927046449.post-89617640418736421942012-10-31T23:29:00.002-04:002013-01-05T15:28:13.807-05:00Salt Experiment ResultsAs previously <a href="http://kneelessmegafauna.blogspot.com/2012/08/new-developments.html">reported</a>, I spent a few weeks this summer conducting a self-experiment on salt sensitivity and blood pressure. The experiment included a three week phase on a low carb whole foods diet with no added salt, followed by a moderately extreme salt loading phase. This post is a summary of my results.<br />
<br />
I learned a lot from the experiment and came out of it with at least one bit of useful information. Will I try to restrict salt in my diet? <a href="http://www.esslab.com/iv/tech/IV-sample-preparation-guide/IV-sample-preparation-files/na.gif">Na</a> (sorry, couldn't resist). I don't think salt restriction can work for me. From now on I will ensure that I get sufficient salt on a daily basis.<br />
<br />
<h3>
Executive Summary</h3>
<br />
Cutting to the chase, these are the main points I learned over the course of the experiment, roughly sorted from most to least interesting.<br />
<br />
1. <u>Salt restriction caused impaired thermoregulation</u>. In hot weather, my cardiovascular system was not able to sufficiently lower my body temperature. This resulted in an elevated heart rate and hypethermia (up to 101.5 degrees in one instance). This can be dangerous, so be careful if you try this at home.<br />
<div>
<br /></div>
<div>
2. <u>No clinically meaningful change in blood pressure</u>. Systolic pressure was unchanged, though salt loading may have caused a small rise in diastolic pressure. This does not rule out long term negative effects from chronic salt loading (see discussion below), but it does show that, as <a href="http://kneelessmegafauna.blogspot.com/2012/09/computational-hemodynamics.html">previously discussed</a>, my kidneys seem to basically work and can regulate my blood pressure through the maintenance of fluid and electrolyte balance in response to changes in my sodium intake.</div>
<div>
<br /></div>
<div>
3. <u>Possible susceptibility to skin infections</u>. Three days into the salt restriction phase, I came down with what was probably a staph infection in my right eyelid. This responded to antibiotics but it came back once I went off them. Since adding back salt I have had no problems with skin infections and no more antibiotics.</div>
<div>
<br /></div>
4. <u>Possible strength loss</u>. I did not perform well in the gym on my usual strength training program.<br />
<div>
<br /></div>
5. <u>My taste for salt adapts quickly to restriction and loading</u>. I experienced no cravings even when my sodium intake was too low. I can't just "listen to my body". Likewise, while the salt loading phase was difficult for the first two or three days, my taste rapidly adjusted to the added salt.<br />
<div>
<br />
<div>
6. <u>Bodyweight changes</u>. I experienced substantial changes in body fluid levels (e.g. 6 pound weight gain within two hours of the transition from the salt restriction to the salt loading phase).</div>
<br />
Conclusion: A low carb paleo diet must include added salt (for me). Can others do without? Perhaps, and some scientists such as <a href="http://thepaleodiet.com/wp-content/uploads/2011/02/The-Nutritional-Characteristics-of-a-Contemporary-Diet-Based-Upon-Paleolithic-Food-Groupsabstract4.pdf">Loren Cordain</a> and Tim Noakes (e.g. <a href="http://talkultra.libsyn.com/rss">this podcast</a> episode 18 at 1:03:50) seem to think they can. Skip ahead to read my further musings on this question.</div>
<div>
<br /></div>
<h3>
Study Design</h3>
<br />
The experiment was conducted in three phases. First, I did a one week lead-in phase (phase I) where I made no changes to diet or salt consumption. The purpose of phase I was to establish a blood pressure baseline through daily morning measurements (see Measurement Methods below).<br />
<br />
This was followed by a three-week sodium restricted phase (phase II) during which I did not add any salt to my food. In addition, during phase II only, I avoided naturally salty foods such as shellfish. My sodium intake during phase II was limited to the sodium in the foods I was eating. Note however that there were one or two restaurant meals per week during this time where I was not able to strictly control for added salt. Sodium consumption on phase II was estimated to be between 800mg and 1000mg per day. phase II was originally scheduled for two weeks, but was extended due to the aforementioned infection and antibiotic use. <br />
<br />
Finally, phase III was a salt-loading phase during which I added an additional 5 grams of sodium to my diet, for a total of nearly 6 grams of sodium per day including the sodium naturally occurring in my food. The supplemental salt during phase III consisted of hand harvested French Celtic sea salt (<a href="http://www.edenfoods.com/store/product_info.php?products_id=105365">Eden Foods, Inc.</a>) and was measured daily on an <a href="http://www.awscales.com/compact-bench-scales/60-amw-1000-digital-bench-scale">AMW-1000</a> digital scale. Because the Eden French Celtic sea salt is approximately 1/3 sodium by weight according to the label, the 5 grams of supplemental sodium per day was provided by approximately 15 grams of sea salt. Note that different varieties of salt will contain different percentages of sodium by weight. Sea salts vary significantly due to variations in residual water content (not, as commonly assumed, by the presence of other minerals). Please consult the label or a friendly analytical chemist for guidance.<br />
<br />
The diet throughout this experiment consisted of meat, fish, eggs, coconut oil, butter, and non-starchy vegetables. In addition, I typically consumed a banana, an ounce (28g) of almonds and a bit of dark chocolate each day. Potassium intake was fairly consistent at around 4 g/day. Table 1 shows a typical day's macronutrient intake. Given the macronutrient ratio, I believe it is likely that the diet was ketogenic.<br />
<br />
Table 1. Approximate daily macronutrient intake. <br />
<br />
<table cellpadding="4" cellspacing="0" style="width: 456px;"> <colgroup><col width="131"></col> <col width="65"></col> <col width="89"></col> <col width="137"></col> </colgroup><tbody>
<tr valign="TOP"> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: 1px solid #000000; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0.04in;" width="131"><b>Macronutrient</b></td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: 1px solid #000000; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0.04in;" width="65"><div style="margin-left: -0.01in; margin-right: 0in;">
<b>grams</b></div>
</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: 1px solid #000000; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0.04in;" width="89"><b>calories</b></td> <td style="border: 1px solid #000000; padding: 0.04in;" width="137"><b>percent (calories)</b></td> </tr>
<tr valign="TOP"> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="131">Carbohydrate</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="65"><div style="margin-left: -0.01in; margin-right: 0in;">
50</div>
</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="89">200</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0.04in; padding-top: 0in;" width="137">6.6%</td> </tr>
<tr valign="TOP"> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="131">Protein</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="65">155</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="89">620</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0.04in; padding-top: 0in;" width="137">20.5%</td> </tr>
<tr valign="TOP"> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="131">Fat</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="65">245</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="89">2205</td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0.04in; padding-top: 0in;" width="137">72.9%</td> </tr>
<tr valign="TOP"> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="131"><b>Total</b></td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="65"><br />
<br /></td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: none; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0in; padding-top: 0in;" width="89"><b>3025</b></td> <td style="border-bottom: 1px solid #000000; border-left: 1px solid #000000; border-right: 1px solid #000000; border-top: none; padding-bottom: 0.04in; padding-left: 0.04in; padding-right: 0.04in; padding-top: 0in;" width="137"><div style="margin-left: -0.02in; margin-right: 0in;">
<b>100%</b></div>
</td> </tr>
</tbody></table>
<br />
<h3>
Measurement Methods</h3>
<br />
Blood pressure was measured daily first thing each morning while seated, with the cuff of an <a href="http://www.amazon.com/Omron-HEM-711-DLX-Automatic-Pressure/dp/B000O5D4TA/ref=sr_1_1?s=hpc&ie=UTF8&qid=1349693302&sr=1-1&keywords=omron+hem+711">Omron HEM-711</a> placed on the left upper arm over the brachial artery. I followed guidelines described by <a href="http://www.scielo.br/pdf/reeusp/v45n1/en_36.pdf">Agena et al</a> (see Chart 2 of the linked paper). Each day's blood pressure value was determined by averaging the first three measurements taken that morning.<br />
<br />
My first measurement of the day was typically higher than the average of the second and third measurements (systolic: +5, diastolic: +4, average over all three phases). This is referred to as the "alarm reaction" and is related to the more commonly known "white coat syndrome", where the presence of a doctor elicits a stress response and therefore an innacurately high blood pressure reading. My alarm reaction seems to be due to the fact that I get slightly stressed out about seeing what my blood pressure is, even when I measure it myself. Therefore I experience a slight rise in blood pressure while waiting to see the first reading each day. I kept all three readings for this experiment. My "true" normal blood pressure is on average slightly lower than these results which include the first "alarm" reading.<br />
<br />
<h3>
Results</h3>
<br />
I summarized my qualitative findings in the executive summary above. If you skipped that because you are not an executive, you can go back and read it now. Below are graphs showing my blood pressure and bodyweight during the three phases. <br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-ARKrkOqLsvo/UInwcMeDciI/AAAAAAAAAKA/Pz1XrRhRgbE/s1600/dia.png" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-ARKrkOqLsvo/UInwcMeDciI/AAAAAAAAAKA/Pz1XrRhRgbE/s1600/dia.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Figure 1: Possible mild elevation in diastolic blood pressure during the salt loading phase. Each point is the average of the three morning blood pressure readings for the day. Red = phase I, green = phase II, blue = phase III. Curves from ggplot2 "geom_smooth()" using default parameters.</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-5YKWm7pxTdo/UInwcqmnnBI/AAAAAAAAAKI/wH9hGwEPRnQ/s1600/sys.png" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-5YKWm7pxTdo/UInwcqmnnBI/AAAAAAAAAKI/wH9hGwEPRnQ/s1600/sys.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Figure 2. No change in systolic blood pressure.</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-JMNRiYfNFXU/UInwdBBG4gI/AAAAAAAAAKQ/V-wJx1aoNnY/s1600/weight.png" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-JMNRiYfNFXU/UInwdBBG4gI/AAAAAAAAAKQ/V-wJx1aoNnY/s1600/weight.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Figure 3: Bodyweight.</td></tr>
</tbody></table>
<br />
Figure 3 shows my daily bodyweight, measured each morning before consumption of any food or fluids. Note that my previous health goal (the <a href="http://www.youtube.com/watch?v=pOqA1CkLf9o">415 deadlift</a>) involved an intentional increase in bodyweight and therefore significant excess calorie consumption. My current diet is lower in calories and Figure 3 therefore should show a long term downward trend in bodyweight.<br />
<br />
Salt restriction clearly resulted in a rapid decrease in bodyweight over the first few days of phase II. There appears to be a stabilization towards the end of the salt restricted phase. The salt loading in phase III produced a very large initial weight gain, followed again by stabilization around the same level seen at the end of the salt restriction phase. As salt is primarily stored in bones and extracellular fluids, an increase in salt would be expected to correspond to an increase in extracellular fluid (since the body's bone mass should change slowly). The bodyweight changes shown in Figure 3 therefore reflect changes in extracellular fluid levels. While salt loading at the levels used in phase III produced a large acute change in body fluids, this was restored to normal over approximately 5 days.<br />
<br />
Since my extracellular fluid volume was evidently restored within 5 days, it is not surprising that salt loading had no significant effect on my blood pressure. What is somewhat surprising was that there was no evidence of a temporary increase in blood pressure during the few days in which my extracellular fluid volume was in fact elevated. This suggests that there is an additional regulatory element working to restore blood pressure homeostasis at a shorter time scale than the dominant kidney-fluid mechanism previously discussed on the blog <a href="http://kneelessmegafauna.blogspot.com/2012/09/computational-hemodynamics.html">here</a>.<br />
<br />
Thanks to <a href="http://mako.cc/">Mako Hill</a> for guidance with <a href="http://ggplot2.org/">ggplot2</a>, without which these plots would look less nice. <br />
<br />
<h3>
Discussion</h3>
<br />
This experiment demonstrated to me that a low carb paleo diet with no added salt is potentially dangerous for me. Impaired thermoregulation is a big deal and would have been a life-threatening issue if I had to hunt for my food in a hot climate. Not only was my body temperature elevated in warm weather, but my pulse was elevated as well, suggesting my cardiovascular system was unable to restore my body temperature to normal. I'm clearly not salt sensitive, and I do not function well with a low salt diet. However, genetic studies suggest the ancestral human genotype is associated with high levels of salt sensitivity and ability to function with very low sodium intakes. How did humans evolve these traits? And why don't I seem to have them?<br />
<br />
<h3>
A Faustian Kidney Bargain</h3>
<br class="Apple-interchange-newline" />
<a href="http://hyper.ahajournals.org/content/40/3/355.full">Susumo Watanabe</a> has proposed in interesting hypothesis about the evolution of sodium metabolism in hominids. The theory is laid out in a 2002 paper called "<a href="http://hyper.ahajournals.org/content/40/3/355.full">Uric Acid, Hominid Evolution, and the Pathogenesis of Salit-Sensitivity</a>," published in the journal Hypertension. It goes something like this. At some point during the evolution of our common ancestor with gorillas and chimpanzees, a series of mutations inactivated the gene for urate oxidase, an enzyme that breaks down uric acid. As a consequence, we have much higher blood levels of uric acid than other mammals. These mutations seem to have occurred between 24 and 8 million years ago, during the miocene, when our ancestors were believed to be subsisting primarily on <a href="http://www.30bananasaday.com/">fruits and leaves</a>. This diet would have been exceptionally low in sodium. Since there is evidence of multiple independent mutations in this gene in multiple primate lineages, it is thought that mutations deactivating urate oxidase were strongly selected.<br />
<br />
In rats, uric acid raises blood pressure acutely, but also causes renal vascular disease via renin/angiotensin systems. This over time makes the rats more salt sensitive. If there is very little salt available, salt sensitivity can be a good thing. Watanabe argues that, where salt is scarce, high uric acid is beneficial (via multiple pathways) for preventing blood pressure from going too low.<br />
<br />
In addition to causing kidney disease, high uric acid causes other problems, like gout, and is associated with heart disease. So this looks like an engineering tradeoff with a number of downsides, but some benefits in the context of a miocene diet that was even lower in sodium than the lowest current estimates for paleolithic diets. The organism with this adaptation is supposed to partially destroy its kidneys on purpose in order to maintain sufficiently high blood pressure. This miocene environment is long gone. However, it is much easier to <a href="http://en.wikipedia.org/wiki/Humpty_Dumpty">break a gene than to put it back together</a>. Our urate oxidase gene has been broken more than once and it would take quite a long time to fix it.<br />
<br />
It's kind of a crazy theory. I'm not sure I believe it but it is interesting to think about.<br />
<br />
<h3>
Some Hypotheses</h3>
<br />
During this experiment, I was eating almost exclusively meat, fish (often with bones), eggs and vegetables, plus added calories from butter, coconut oil and olive oil. The diet was grain, legume and dairy free and, as mentioned, possibly ketogenic. This would be considered by many online diet and health personalities to be a good low carb paleo diet, even though of course processed fats like butter and coconut oil are not Paleolithic foods.<br />
<br />
So I want to discuss a few possible ways to resolve the apparent impossibility of eating this way without added salt.<br />
<br />
<h3>
Hypothesis 1: Low Carb, Low Crab, or Low Salt: choose any two</h3>
<br />
I have been eating a low carb diet, and my experiment suggests that, in that context, low salt is not a good idea. It is possible that a healthy human diet can be either low in carbohydrates or low in salt, but not both.<br />
<br />
A great deal of evidence suggests that ketosis was not the norm for our paleolithic ancestors (see e.g. <a href="http://humanoriginsleiden.org/index.php/projects?view=publication&task=show&id=210">Kuipers et. al. 2012</a>
for a thorough review of paleolithic diet research). In fact it would
have been quite a struggle for me to eat this sort of macronutrient
ratio without modern refined fats such as butter and coconut oil. Or
ready access to marine mammal blubber (but then again the Inuit are not <u>my</u> paleolithic ancestors).<br />
<br />
In contrast to the online paleo diet scene, most low carb diet advocates seem to
line up behind the recommendation for ample supplementary
salt. My result accord with that clinical
experience. Low carbohydrate diets are usually said to have a diuretic effect in this community, at least in the initial stages (e.g. <a href="http://www.proteinpower.com/drmike/saturated-fat/tips-tricks-for-starting-or-restarting-low-carb-pt-ii/">M.R. Eades</a>, <a href="http://www.phlaunt.com/lowcarb/19058097.php">Jenny Ruhl</a>). It is possible that my problems
were caused by the interaction between diet-induced ketosis
and salt restriction, and I would have done just fine without
salt if I had some more carbohydrates. This hypothesis would be straightforward to test.<br />
<br />
In order to keep my sodium intake sufficiently low during the salt restriction phase, I had to remove shellfish such as oysters and mussels from my diet. Crab is also salty and makes for a handy pun. It seems likely that daily shellfish consumption would have pushed my sodium intake into the healthy range. While shellfish does not get much attention these days in the paleo club, there is ample support (again see <a href="http://humanoriginsleiden.org/index.php/projects?view=publication&task=show&id=210">Kuipers et. al.</a>) that it was an important contributor to actual paleolithic nutrition.<br />
<br />
<h3>
Hypothesis 2: Humans must drink blood. Or eat salt.</h3>
<br />
File this one in the "<a href="http://www.barnesandnoble.com/u/paranormal-teen-romance-dark-romance/379002329/">teen paranormal romance</a>" department. This hypothesis states that the ancestral human diet was not as low in salt as commonly assumed.<br />
<br />
Sodium is the body's primary extracellular cation, and most of it is located <a href="http://www.merckmanuals.com/home/hormonal_and_metabolic_disorders/electrolyte_balance/sodium.html">in the blood and other extracellular fluids</a>. A pint of blood contains about 1.6 grams of sodium (see, e.g., these livestock <a href="http://onlinelibrary.wiley.com/doi/10.1002/9780470752425.app3/pdf">reference ranges</a> for blood sodium). That much blood per day should have been more than enough to push me into the healthy range of sodium consumption. On the other hand, salt depletion set in pretty quickly for me (probably 3-4 days), so this hypothesis assumes that fresh blood was consistently available to inland populations that did not have ready access to shellfish or sea water.<br />
<br />
I find this hypothesis intriguing because of the fact that my putative ancestors were commanded not to drink blood (<a href="https://net.bible.org/?ref=nbt#!bible/Genesis+9:4">Genesis 9:4</a>, <a href="https://net.bible.org/?ref=nbt#!bible/Leviticus+17:13">Leviticus 17:13</a>, <a href="http://bible.org/seriespage/deuteronomy-12">Deuteronomy 12:15-16</a>), and that <a href="http://www.chabad.org/library/article_cdo/aid/82678/jewish/Koshering-Meat.htm">salt is used in this tradition specifically to remove blood from meat</a> before it is eaten. Presumably blood drinking was outlawed because it was thought to spread diseases and not because of <a href="http://www.stepheniemeyer.com/twilightseries.html">tacky pop-culture connotations</a>. Were my ancestors salting their meat not just for its preservative qualities, but also to make up for the reduction in sodium intake due to their prohibition on drinking blood?<br />
<br />
<h3>
Hypothesis 3: I'm Not (Genetically) a Paleolithic Human</h3>
<br />
Some say the human genome has hardly changed in the past 10,000 years. However, the hard evidence points to a number of significant evolutionary changes since the advent of agriculture, the classic example being lactase persistance (see <a href="http://the10000yearexplosion.com/">Cochran and Harpending</a> 2009 for a thorough argument on the rapidity of recent human evolution). Genes associated with hypertension and salt sensitivity are also apparently under strong evolutionary pressure. Alan Weder discusses this in an <a href="http://hyper.ahajournals.org/content/49/2/260.full">article</a> published in 2007 in the journal Hypertension about evolution and hypertension. It is worth reading as an example of excellent science writing.<br />
<br />
My experiment clearly demonstrates that I am not salt sensitive. This is not surprising given my European ancestry. As discussed by <a href="http://hyper.ahajournals.org/content/49/2/260.full">Weber</a>, the genetics of salt resistance seem to correlate with adaptations to colder climates. It seems possible that in the course of such adaptation, my ancestors lost the ability to function optimally on a low salt diet.<br />
<br />
<h3>
Is a High Salt Diet Safe?</h3>
<br />
It is possible that, as much of mainstream medicine believes, a high salt diet actually is unhealthy over the long term. There is nothing in this experiment that contradicts that belief. Just because I am resistant to the short term blood pressure effects of salt loading, that does not mean I am immune to whatever long term negative effects a high salt diet may have. While epidemiological studies have their problems, it seems unwise to discount their findings altogether.<br />
<br />
<a href="http://hyper.ahajournals.org/content/50/1/161.full">Edward Frohlich</a> has argued that, notwithstanding the fact that most people's blood pressure does not respond to acute increases in sodium intake, sodium is nevertheless responsible long-term for increases in blood pressure. He argues that excess salt causes kidney damage over time (as with uric acid this is mediated by renin/angiotensin systems), resulting long-term in an increase in blood pressure. While much of this research is based on studies done on rats (including those of the "<a href="http://www.criver.com/en-US/ProdServ/ByType/ResModOver/ResMod/Pages/SHRRat.aspx">spontaneously hypertensive</a>" variety), this line of thought is worth looking into and I will continue to do so.<br />
<br />
<h3>
Further Research is Needed</h3>
<br />
Studies always end with the statement that further research, and therefore research funding, is required. Well, I don't need funding but I will go a little further than a call for further research. Here are some ideas for areas of study and self experimentation.<br />
<br />
<ul>
<li>High carb low salt diet -- measure bodyweight and thermoregulation (e.g. via controlled hot baths or showers) over 5 day intervention period.</li>
<li>Anthropological studies of salt and carbohydrate consumption among hunter-gatherers. Including seasonal variation. Genetics would be expected to play a significant role as there is ample evidence for recent evolution of salt sensitivity.</li>
<li>Theories and evidence for salt use among paleolithic people. Support for consistent blood and/or shellfish consumption? Evidence for use of natural salt deposits?</li>
<li>Sodium consumption and skin infections. Is salty sweat bacteriostatic within in sweat glands? Is low sodium consumption associated with skin infections? How salt sensitive is staph aureus? How about p. acnes? Have comensal skin bacteria evolved higher or lower levels of salt sensitivity? Are there differences between human populations (e.g. African vs. European skin flora)?</li>
<li>Evidence for genetic selection of salt sensitivity in neanderthals. Is it possible I inherited some of my salt-related genetics from my neanderthal ancestors? If salt resistance is associated with adaptation to cold environments (see <a href="http://hyper.ahajournals.org/content/49/2/260.full">Weber</a>), neanderthals would be expected to show these adaptations, and if they conferred a selective advantage, they should have been propagated if passed to human populations.</li>
</ul>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com3tag:blogger.com,1999:blog-2658003869927046449.post-32353511573972917092012-09-16T15:00:00.000-04:002013-01-05T15:28:47.085-05:00Computational HemodynamicsThis is a quick update on salt, and a digression about computation and blood pressure control. Read all the way to the end for a grain of salt advisory on the carbohydrate-insulin hypothesis.<br />
<br />
My <a href="http://kneelessmegafauna.blogspot.com/2012/08/new-developments.html">salt experiment</a> is progressing and I've completed a 6 day baseline period, followed by a 3 week salt restriction period during which I consumed approximately 800-1,000 mg of sodium per day. I am now half way through a 2 week salt loading phase where I am consuming about 6,000 mg of sodium per day. It is quite a challenge to eat this much salt, though my taste buds have now gotten used to it.<br />
<br />
Results? There has not really been a noticeable change in blood pressure between the three phases. Blood pressure during salt loading is almost certainly the same as the baseline diet, which was fairly low in salt to begin with. I'm still reviewing the data on the salt restriction phase, as there may have been a small drop there. I will report in more detail later.<br />
<br />
Severe salt restriction had some negative side effects, most significantly an impairment in my body's ability to maintain a stable core temperature. In a warm environment, I might experience an increase in heart rate, and ultimately an elevated core temperature (up to 100.5 in one case). I also noticed a substantial drop in exercise performance. I was clearly dehydrated during this period, as evidenced by a drop in body weight. According to a google book called <a href="http://www.amazon.com/Interface-Neurology-Internal-Medicine/dp/0781779065/ref=sr_1_1?s=books&ie=UTF8&qid=1347762726&sr=1-1&keywords=0781779065">The Interface of Neurology and Internal Medicine</a> (2007), salt restriction and dehydration can result in <a href="http://books.google.com/books?id=SRIvmTVcYBwC&pg=PA691&lpg=PA691&dq=salt+impaired+thermoregulation&source=bl&ots=HOrDm6IaqW&sig=NO1Fu0wJK6nOHPBu-ebnLkklst0&hl=en#v=onepage&q=salt%20impaired%20thermoregulation&f=false">impaired thermoregulation</a> possibly leading to heat stroke. I believe dehydration and the resulting drop in blood volume limits cardiac output, thereby preventing the cardiovascular system from performing its temperature regulatory functions.<br />
<br />
<h3>
Infinite Gain</h3>
<br />
In a former incarnation I was an electrical engineer.<br />
<br />
Beloved of electrical engineers the world over, the operational amplifier (a.k.a. the "op amp") has been a mainstay of circuit design at least since the mid-1960s, when the first integrated circuit operational amplifier was introduced. An op amp has two inputs and one output, with the output dependent on the difference in voltage between the inputs, multiplied by a gain factor.<br />
<br />
An ideal op amp by itself has effectively an infinite gain. This means it is not going to make a very useful amplifier unless it is built into a circuit that incorporates negative feedback. In this configuration, as articulated by Paul Horowitz and Winfield Hill in "<a href="http://books.google.com/books?id=bkOMDgwFA28C&pg=PA177&lpg=PA177#v=onepage&q&f=false">The Art of Electronics</a>," the op amp will do "whatever is necessary to make the voltage difference between the inputs zero."<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-hNSYg5VnuFc/UFVEp8Vrd9I/AAAAAAAAAIU/I5ybh1ntTTw/s1600/500px-Op-Amp_Inverting_Amplifier.svg.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="233" src="http://1.bp.blogspot.com/-hNSYg5VnuFc/UFVEp8Vrd9I/AAAAAAAAAIU/I5ybh1ntTTw/s400/500px-Op-Amp_Inverting_Amplifier.svg.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">An operational amplifier in the inverting closed-loop configuration. Rf provides negative feedback such that the voltages at the (+) and (-) inputs become equal. The circuit designer can manipulate Rin and Rf to produce the desired relationship between Vin and Vout.</td></tr>
</tbody></table>
<br />
<br />
Since the op amp is so useful in engineering, one might expect to find something like it in evolved biological systems that incorporate regulatory elements and negative feedback. In fact, there does appear to be an "infinite gain" element in the human blood pressure regulation system.<br />
<br />
<h3>
Computational Hemodynamics</h3>
<br />
In 1966, Arthur Guyton and Thomas Coleman developed a computer model of blood pressure regulation. The model was put together based on prior research on the various systems that work together to regulate blood pressure, including hormones (renin, angiotensin, aldosterone, antidiuretic hormone), heart pumping parameters (including pulse and stroke volume), fluid dynamics, electrolytes, local blood flow control, and various other factors. In a <a href="http://hyper.ahajournals.org/content/16/6/725.full.pdf">paper published in 1990</a> in the journal Hypertension, Guyton discusses the discovery he made using this computer model of an infinite gain regulatory element.<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-Jdgyl0MFC4M/UFVJP7K53BI/AAAAAAAAAIo/6p3bBROVTYE/s1600/_P1A0180.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-Jdgyl0MFC4M/UFVJP7K53BI/AAAAAAAAAIo/6p3bBROVTYE/s1600/_P1A0180.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">1966 was a long time ago in the computing world. Guyton and Coleman may have needed one of these to program their blood pressure model. Image from "Introductory Computer Programming" by Fredric Stuart, John Wiley & Sons, Inc. 1966.</td></tr>
</tbody></table>
After Guyton and Coleman started playing around with their computer model (did I mention it was 1966!), they saw some unexpected results. They increased one variable -- namely total peripheral resistance -- that "everyone already understood" would cause chronic hypertension. Instead, as Coleman reported to Guyton, "the patient developed hypertension all right, but the pressure came back to normal after a few days." Guyton and Coleman saw that the kidney's ability to regulate fluid and electrolytes was effectively an infinite gain feedback system: like an op amp, the kidney would do whatever was necessary to maintain stable blood pressure. While this surprised them at first, they found that this property could explain earlier observations that had been difficult to understand.<br />
<br />
As Guyton stated in the 1990 paper, "the infinite gain property of the kidney-fluid mechanism for pressure control is so dominating that it will not allow a factor from outside this mechanism to alter the blood pressure permanently unless the kidney-fluid mechanism is itself altered at the same time." In other words, if you are looking for a cause for a long term change in blood pressure, look for something that is affecting kidney function.<br />
<br />
Here is an except of a schematic diagram of Guyton's 1972 blood pressure model (this may be a revised version of the original 1966 model). A shrunken version of the full diagram is included at the end of this post. It's so big that it is worth checking out the fill size image, which you can get <a href="http://patf-biokyb.lf1.cuni.cz/wiki/dokumenty/guyton">here</a>.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-TQuEe-5bAH4/UFYEQlxg6sI/AAAAAAAAAJQ/rJgMDdfTdOw/s1600/guyton_schema-1972-zoom-web.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-TQuEe-5bAH4/UFYEQlxg6sI/AAAAAAAAAJQ/rJgMDdfTdOw/s1600/guyton_schema-1972-zoom-web.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A small segment of the Guyton 1972 schematic.</td></tr>
</tbody></table>
<br />
<br />
<h3>
Biology as Computation</h3>
<br />
I think this story is a good example of a successful computational approach to a biological question. We can view the human blood pressure regulatory system as a computational system. It reads a variety of inputs and "computes" the organism's blood pressure. If we can accurately model the system's individual elements (based on lots of reductionist basic science) we can try to simulate the whole thing in a computer.<br />
<br />
This story also shows that a reductionist approach to biology can mislead. Viewed in isolation, it seemed obvious to everyone that an increase in "total peripheral resistance" would result in a long-term rise in blood pressure. This was consistent with the fact that patients with hypertension typically also show an increased total peripheral resistance. However, in other cases where there is a clear primary cause for a rise in total peripheral resistance (e.g. multiple amputations), scientists frequently observed no long term increase in blood pressure.<br />
<br />
The computer model helped provide an answer to these riddles. Instead of relying on an intuitive understanding of a single element, it let us watch what happens when all of the computational elements are allowed to interact. It then became obvious to Guyton and Coleman that the kidney's fluid regulation mechanism was powerful enough to override other factors that might try to drive blood pressure up or down. It could then be hypothesized that the increased total peripheral resistance seen in hypertensives was in fact a consequence, and not a cause, of elevated blood pressure. Work could then proceed on how exactly this came about.<br />
<br />
<h3>
Beyond Blood Pressure</h3>
<br />
Some complex systems may sometimes exhibit simple and comprehensible behaviors, while other complex systems will not. Computational approaches might help us figure out which is which. Computational approaches may be required when purely reductionist thinking is not enough. In other cases, when the basic "computational units" of the system being modeled are not individually well understood, a computational approach might lead us <a href="http://kneelessmegafauna.blogspot.com/2012/05/garbage-in-garbage-out-at-new-york.html">absolutely nowhere</a>. And as anyone who has ever tried to build a complex system can tell you, if it is not extensively validated, it is almost guaranteed to <a href="http://www.zerohedge.com/news/explaining-knightmare">break</a>.<br />
<br />
Blood pressure regulation is complex, though it is probably quite simple compared to many other biological systems. To me the diagram below looks about as complex as <a href="http://xenia.media.mit.edu/~mcnerney/2009-4004/i4004-schematic.gif">this schematic</a> for the Intel 4004 microprocessor, introduced in 1971. The infinite gain property of kidney fluid regulation, discovered because of a computer model, allows for a powerful simplification. If the kidney is really driving the blood pressure boat, we could safely ignore most of the complexity of the total system and look only at the kidney's health and its specific regulatory drivers. Many other complex systems will not be reducible in this way.<br />
<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-STToVYKnPRo/UFYeU_dKjQI/AAAAAAAAAJs/z99aR_E31bg/s1600/grainofsalt.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-STToVYKnPRo/UFYeU_dKjQI/AAAAAAAAAJs/z99aR_E31bg/s1600/grainofsalt.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Grain of salt advisory.</td></tr>
</tbody></table>
Consider this next time someone says <a href="http://garytaubes.com/works/books/good-calories-bad-calories/">carbs drive insulin which drives fat storage</a>.
Insulin works in a complex web of biological
computational elements, including the mother of all biological
computers, the human brain. Insulin viewed in
isolation may or may not give us the answer. This is why my ears glaze
over a bit when I hear someone start talking about "<hormone <i>du jour></i> resistance." I'm not interested in the behavior of a
single wire in a complex web. I want to know how the whole thing works.<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-Pf1yu4SAHf0/UFVRj6-seaI/AAAAAAAAAI8/OYJm04V2CYo/s1600/guyton_schema+1972.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="628" src="http://2.bp.blogspot.com/-Pf1yu4SAHf0/UFVRj6-seaI/AAAAAAAAAI8/OYJm04V2CYo/s640/guyton_schema+1972.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Blood pressure regulation. It's complicated. From Guyton 1972.</td></tr>
</tbody></table>
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com0tag:blogger.com,1999:blog-2658003869927046449.post-24203855450894101842012-08-25T17:30:00.000-04:002013-01-05T15:29:36.024-05:00Goals, Salt and ViromesHere's an update on what's been going on here at megafauna central. Health goals, salt sensitivity, and the microvirome.<br />
<br />
Eagle-eyed readers will have noticed that the quote in the mast-head has changed. The original version was "science is the disbelief in the authority of experts." I heard this quoted by <a href="http://en.wikipedia.org/wiki/Michael_Vassar">Michael Vassar</a> on the Bulletproof Executive podcast (<a href="http://www.bulletproofexec.com/podcast-transcript-14-michael-vassar-of-the-singularity-institute/">episode 14</a>). A reader told me that he was researching the quote and was unable to find a reliable attribution to Feynman. The closest Feynman quote he could find was "science is the belief in the ignorance of experts." This version <a href="http://books.google.com/books?id=s6LzV_U6PskC&pg=PA187&lpg=PA187&dq=the+pleasures+of+finding+things+out+feynman+%22science+is+the+belief+in+the+ignorance+of+experts%22&source=bl&ots=OXqotxcgDG&sig=1TYKaCnHS0VFLhFo-_JyZxGn5BA&hl=en&sa=X&ei=8DM5ULyKJMPm0QGWgoFg&ved=0CC8Q6AEwAA#v=onepage&q=the%20pleasures%20of%20finding%20things%20out%20feynman%20%22science%20is%20the%20belief%20in%20the%20ignorance%20of%20experts%22&f=false">appears</a> in an essay called "What is Science?", which is included among other places in a collection called "The Pleasure of Finding Things Out" (Perseus, 1999). Now I like the original, wrong version better, since it is less confrontational and fits my personality. So I imagined myself going all <a href="http://www.tabletmag.com/jewish-news-and-politics/107779/jonah-lehrers-deceptions">Jonah Lehrer</a> and sticking with it. However reason prevailed and I changed the quote to the one I'm pretty sure Feynman actually said. Getting a quote wrong in a podcast interview is understandable, but I should have done a better job of fact checking. As it is, it looks like I may have permanently polluted the Internet. Sorry!<br />
<br />
<h3>
Health Goals</h3>
<br />
I took a break from experimentation while on the home stretch for my 2012 health goal, which I mentioned at the end of my <a href="http://kneelessmegafauna.blogspot.com/2012/07/butter-not-like-statin-after-all.html">last butter post</a>. Last week I completed that goal with a <a href="https://www.youtube.com/watch?v=pOqA1CkLf9o">415 pound deadlift</a>, thanks in part to high butter consumption which allows me to keep my calorie intake high and maintain my bodyweight (<a href="http://twitter.com/KMegafauna">twitter subscribers</a> have already seen the video, which is low quality and not terribly interesting).<br />
<br />
My next health goal is to achieve a reasonably fast <a href="http://www.achievement.org/autodoc/page/ban0int-1">one mile run</a>. I don't run and never really have, so I'm hoping to find some "low hanging fruit" by exploring another fitness domain. I also have no idea what a reasonable goal might be, so I'll just muddle around for a few months and see where I end up. I'll be closely watching my resting heart rate and expect some short-term improvements there. I will be writing about my protocol and progress.<br />
<br />
Now that my 2012 health goal is complete, I have a little time for experiments. <br />
<br />
<h3>
Salt Sensitivity</h3>
<br />
For a while I have been interested in lifestyle modifications that might affect blood pressure. While my blood pressure is considered normal, my systolic (the high number) is at the high end of the normal range.<br />
<br />
It seems clear that salt raises blood pressure significantly for some people, and in those people, excess salt consumption is associated with a host of bad effects. These folks are called "salt sensitive." For others, blood pressure seems to be unaffected or even decrease when excess salt is added to the diet. These folks are called "salt resistant." I would like to find out which category I fall into.<br />
<br />
The following graph from <a href="http://www.clinchem.org/content/52/3/352.full">Sanada et al</a> (Clinical Chemistry 2006) gives a good picture of what's going on with short-term changes in salt intake. It shows the daily sodium excretion of salt sensitive and salt resistant individuals during a dietary protocol in which salt is first decreased, then increased, and then returned to baseline (note, since the molecular mass of sodium is about 23, multiply the mmol values by 23 to determine milligrams of sodium per day).<br />
<br />
It appears that salt resistant individuals rapidly increase their sodium excretion when the salt content of the diet goes up (this is accomplished through a reduction in renal sodium reabsorption, hence excess urinary sodium excretion). The net effect should be that the body maintains sodium homeostasis notwithstanding the rapid change in intake. Salt sensitive individuals appear to be slower to make that adjustment, as evidenced by the lag in the sodium excretion curve during the salt loading phase. Given the lag, it would appear that salt sensitive individuals might accumulate sodium in the body on a high salt diet, though it is unclear if this normalizes over a longer term (I haven't gone deep enough into the research to see if that is the case).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-yR0VQwspmAQ/UDkfm_AC9SI/AAAAAAAAAIA/mouzXgd4h7g/s1600/Sanada+sodium+excretion.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-yR0VQwspmAQ/UDkfm_AC9SI/AAAAAAAAAIA/mouzXgd4h7g/s1600/Sanada+sodium+excretion.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Effect of dietary sodium on sodium excretion in SR (○) and SS (▪) hypertensive Japanese. From Sandana et al (Clinical Chemistry 2006).</td></tr>
</tbody></table>
One recent paper suggests that salt resistance confers advantages in maintaining body temperature homeostasis (see <a href="http://www.nature.com/hr/journal/v34/n6/full/hr201127a.html">Muller et al</a>, Hypertension Research 2011). I had always assumed that salt sensitivity was the ancestral state and that salt resistance traits were associated with agricultural cultures that used salt to preserve food. However, the Muller paper suggests to me that salt sensitivity might actually be an adaptation for <a href="http://phys.org/news95954919.html">persistence hunting</a> in hot climates by allowing improved thermoregulation. I have no idea if the genomics work on that question has been done.<br />
<br />
<h3>
Are You Salt Sensitive? </h3>
<br />
If your blood pressure is more than 100-110 over 70-75 (the norms <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CEkQFjAH&url=http%3A%2F%2Fwww.direct-ms.org%2Fpdf%2FEvolutionPaleolithic%2FEaton%2520Ancestral%2520biomedical%2520environment%252007.pdf&ei=7iU5UIDCOvC30gGezYGoDQ&usg=AFQjCNHdt4rAiv5HpbfWnezQLORIxoMp2Q&cad=rja">reported for hunter-gatherers</a>), perhaps it makes sense to find out if you are salt sensitive.<br />
<br />
I reviewed the medical protocols for diagnosing salt sensitivity and found them to be fairly intensive. They seem to be confined to clinical research settings at this point. In other words, doctors don't know, and can't find out, if their patients are salt sensitive.<br />
<br />
There seem to be two recognized approaches for diagnosing salt sensitivity in research settings. In the first, a low salt diet (~1g of sodium per day) is followed for two weeks followed by a high salt diet for another two weeks. A second standardized approach, described by <a href="http://www.ncbi.nlm.nih.gov/pubmed/3522418">Weinberger et al</a> in 1986, is much quicker. It uses IV saline solution for the loading phase, followed by a low salt diet and the administration of furosemide, a diuretic that decreases renal reabsorption of sodium.<br />
<br />
At least one study has shown that the two techniques are not well correlated with each other (see <a href="http://www.nature.com/jhh/journal/v16/n4/full/1001375a.html">de la Sierra 2002</a>, Journal of Human Hypertension). Since I am not interested in my response to diuretics, I am running myself through the dietary version of the test. I am one week into the low salt phase and have seen no noticeable change in blood pressure thus far. That's not unexpected though, since my baseline diet was pretty low in salt. I'll know much more once salt loading kicks in at the end of this week. What is most interesting to me so far is that I have had absolutely no cravings for salt.<br />
<br />
<br />
In the mean time, health authorities strongly advise everyone to restrict salt, despite the fact that they have no idea what effect this will have on you in particular. Lemmings will jump. Ostriches may hide their heads from the truth.* I prefer to get the information I need to make good decisions.<br />
<br />
<br />
* Yes, I understand that neither of these statements is true. I am lying about animals for rhetorical effect.<br />
<br />
<h3>
Microbiome </h3>
<br />
In microbiome news, I received the results of my <a href="http://www.metametrix.com/test-menu/profiles/gastrointestinal-function/dna-stool-analysis-gi-effects">Metametrix</a> stool profile. It is pretty interesting but I believe this type of data is of very limited usefulness at this point. The profile works by sequencing the ribosomal RNA of the bacteria in your stools. This gives you an idea of the mix of "species" of bacteria that are present and in what quantities they appeared in your stools on that particular day. What information is missing given current technology?<br />
<ul>
<li>Changes in the microbiome over time</li>
<li>Presence and expression of genes. Microbes are exceptionally promiscuous and share DNA via plasmids, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202279/">phage</a>, and other mechanisms. 16S ribosomal RNA does not tell us what genes are there or to what degree they are expressed</li>
<li>Where the bacteria are located. Bacteria can colonize multiple niches (e.g. lumen vs. mucosal layers) and these differences can have meaningful effects</li>
<li>Behavior of the bacteria that are there. Microbes communicate with each other and with the immune system. What are they saying?</li>
</ul>
I mentioned phage above. While it is well known these days that bacteria form an important part of the human digestive tract, it is not as widely appreciated that viruses are also a significant component. Viruses that infect bacteria, known as bacteriophages or "phages" for short, are the most abundant life forms on earth. If they were so inclined, they could link hands and stretch from one end of the galaxy to the other. And back. By comparison, humans could get 1/10 of the way to Mars, and would almost certainly be accompanied by <a href="https://www.youtube.com/watch?v=WZorfXa5pBc">terrible music</a>.<br />
<br />
Phage seem to represent the majority of all genetic variability on the planet. They associate with our gut microbiota and change in response to dietary interventions (see <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202279/">Minot et al</a>, Genome Research 2011). Scientists seem to be at the very early stages of figuring out what phages are out there, what they look like, and what they might be doing. I don't think anyone has a clue about the impact they have on human health. So until these questions are answered, keep plenty of salt grains at the ready for the next time you hear a definitive-sounding pronouncement about the microbiome.Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com1tag:blogger.com,1999:blog-2658003869927046449.post-5621778312022726432012-07-09T09:30:00.000-04:002012-07-25T19:42:59.702-04:00Recipe SectionIf this blog were a mainstream health book, this would be the obligatory recipe section. So if you are interested in my take on minimalist high-butter cuisine, read on.<br />
<br />
<br />
<h3>
Bulletproof Mussels</h3>
<a href="http://4.bp.blogspot.com/-JYBF9qJB-MQ/T_TBKp-_XSI/AAAAAAAAAGM/BZIFOUwhdjQ/s1600/_MG_1332-thumb.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://4.bp.blogspot.com/-JYBF9qJB-MQ/T_TBKp-_XSI/AAAAAAAAAGM/BZIFOUwhdjQ/s1600/_MG_1332-thumb.jpg" /></a><br />
<span style="background-color: white;">(inspired by <a href="http://www.bulletproofexec.com/how-to-make-your-coffee-bulletproof-and-your-morning-too/">bulletproof coffee</a>)</span><br />
<span style="background-color: white;">2 lbs mussels</span><br />
1/2 stick Kerrygold butter<br />
<br />
1. Clean mussels and add to large stockpot with 1 cup of water. Cover and simmer for 15 minutes.<br />
2. Discard shells and remove meat to a bowl, leaving the broth in the stockpot. <span style="background-color: white;">Melt butter in the broth. Whip with emersion blender. Pour over mussels and serve immediately.</span><br />
<br />
<br />
<br />
<h3>
Spinach Soup</h3>
<br />
1 lb spinach<br />
1/2 stick Kerrygold butter<br />
1/2 tsp ground cumin<br />
1/2 tsp salt<br />
<br />
1. Rince spinach and add to large stockpot with 1 cup of water. Bring to a boil, cover and simmer for 3-5 minutes.<br />
2. Add butter, cumin and salt. Blend with emersion blender. Serve immediately.<br />
<br />
<br />
<br />
<h3>
Butter Poached Salmon</h3>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-XO9ijkCN2SA/T_TAvcVhBmI/AAAAAAAAAGE/KMrqP8A891o/s1600/_MG_1392-thumb.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://3.bp.blogspot.com/-XO9ijkCN2SA/T_TAvcVhBmI/AAAAAAAAAGE/KMrqP8A891o/s1600/_MG_1392-thumb.jpg" /></a></div>
<br />
1 lb salmon, cubed<br />
1/2 stick Kerrygold butter<br />
<br />
1. Melt butter in small saucepan. Add salmon, cover and simmer for 5 minutes or until cooked through.<br />
2. That's it (or were you hoping you'd get to use the blender?). Salt to taste and serve immediately.<br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com0tag:blogger.com,1999:blog-2658003869927046449.post-4343938600393906132012-07-04T17:57:00.000-04:002013-01-05T15:30:29.108-05:00Butter Not Like a Statin After All?<span style="background-color: white;">I began my <span style="background-color: white;">original </span><a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html" style="background-color: white;">butter experiment</a> without a hypothesis about the effects of butter on cholesterol. I was tracking blood lipids so that I could identify any possible adverse reactions. After initially seeing a positive change, the numbers started to go the wrong way, with HDL dropping and non-HDL going up. At the same time, I had switched from the Kerrygold butter I usually used to a local brand from my farmer's market. It was supposed to be "100% grass fed," but it did not have the deep yellow hue of the Kerrygold, so I suspected it could be responsible for the adverse results. After a day or two using an Icelandic brand (Smjor), I</span><span style="background-color: white;"> decided for the remainder of the experiment to test only Kerrygold butter. A few days after the switch back, the numbers moved back in the positive direction. I tracked for a few more weeks and then reported my <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">initial results here</a>.</span><br />
<span style="background-color: white;"><br /></span>
After the <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">original post</a>, I spent about three more weeks on the same diet (1/2 stick of Kerrygold butter per day), followed by three weeks of butter elimination (during this elimination phase, there was some increase in coconut oil as a partial substitute for the butter calories). Finally, I went back on a high-butter diet for an additional five weeks. During this last phase I decided to double down and eat a full stick of Kerrygold butter every day (about 112 grams of butter and 90 grams of fat). The diets were otherwise similar, though I was likely consuming more total calories during the high-butter phases. Data points were generally taken weekly, on Sunday afternoons (not fasted, but I don't believe it makes much difference, since I am not measuring triglycerides).<br />
<span style="background-color: white;"><br /></span>
<span style="background-color: white;">Based on the additional data I can report that</span><span style="background-color: white;"> the addition of butter to my diet may have increased my HDL cholesterol. However, it has not had a convincing long-term effect on my non-HDL cholesterol. The HDL remains elevated from before, but non-HDL readings are consistent with my average numbers over the past three years or so. </span><span style="background-color: white;">My working hypothesis at this point is that the change in non-HDL I observed originally was a temporary disturbance of homeostasis. This may have been due to the butter or to another unknown cause.</span><br />
<span style="background-color: white;"><br /></span>
<span style="background-color: white;">I also believe this data suggests that different brands of butter can have different effects on cholesterol values. I will show this data below, though given the design of this experiment, I will not be able to prove it without a follow-up experiment. However, I am satisfied with my original concern, which is that the addition of a good brand of butter to my diet does not seem to have any measurable adverse effect on cholesterol measurements.</span><br />
<br />
<h3>
Results</h3>
<br />
The additional data points are shown in the two plots below. <span style="background-color: white;">The four green points show the data that was dropped from the original data set because I was not using Kerrygold butter. The last five points are for the latest diet where I am eating a full stick of butter per day.</span><br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><div style="text-align: -webkit-auto;">
<br /></div>
<a href="http://4.bp.blogspot.com/-5wrOao4A-Tg/T_CxCOgDXvI/AAAAAAAAAFc/1BAaChFmipQ/s1600/hdl-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-5wrOao4A-Tg/T_CxCOgDXvI/AAAAAAAAAFc/1BAaChFmipQ/s1600/hdl-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">HDL measurements over time. Red points indicate control. Blue and green points indicate experimental group with consumption of at least 0.5 sticks of butter per day for at least 7 days prior to testing (blue=Kerrygold). No statistically significant difference in control vs. experimental measurements when green points are included. Trend line is for red points only.</td></tr>
</tbody></table>
<div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-eBOOfJOKEwg/T_CyDNEkuPI/AAAAAAAAAFk/rtuhe_fiVXo/s1600/nonhdl-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-eBOOfJOKEwg/T_CyDNEkuPI/AAAAAAAAAFk/rtuhe_fiVXo/s1600/nonhdl-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Non-HDL cholesterol over time. No statistically significant difference between control vs. experimental measurements when green points are included. Trend line is for red points only.</td></tr>
</tbody></table>
<div style="text-align: center;">
<br /></div>
<div style="text-align: center;">
</div>
<div style="text-align: -webkit-auto;">
The next two plots show the same data, zoomed in to show points from the beginning of the original butter experiment to the present time. The three red points are the latest butter-elimination phase.</div>
<div style="text-align: -webkit-auto;">
<br /></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-3kjdmInrXxc/T_C0PzFJ1PI/AAAAAAAAAFw/Ih9ieyKv4j8/s1600/hdl2-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-3kjdmInrXxc/T_C0PzFJ1PI/AAAAAAAAAFw/Ih9ieyKv4j8/s1600/hdl2-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Trend line for blue points.</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-OG4DuuGUu2Y/T_C0QPC4NNI/AAAAAAAAAF4/s32f5bEXKQU/s1600/nonhdl2-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-OG4DuuGUu2Y/T_C0QPC4NNI/AAAAAAAAAF4/s32f5bEXKQU/s1600/nonhdl2-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Trend line for blue points.</td></tr>
</tbody></table>
<div style="text-align: -webkit-auto;">
<br /></div>
<div style="text-align: -webkit-auto;">
<br /></div>
<div style="text-align: -webkit-auto;">
Overall, I think there is some basis for concluding that added butter is having a positive effect on HDL, although the results are not statistically significant when the green points are included. However, it is also possible that some other factor is concurrently causing my HDL to increase.<br />
<br />
The trend towards positive HDL outliers has continued in the butter dataset and is especially strong in the latest readings where a full stick per day is consumed, suggesting a dose-response relationship. My last three readings are all greater than 100, which is the meter's measurement limit for HDL cholesterol. Since I am computing non-HDL cholesterol as Total <u>minus</u> HDL, this measurement limitation will inflate the non-HDL points by an indeterminate amount at the same time as it underestimates HDL. The highest reading ever recorded in the control dataset is 83, while the butter dataset has 5 readings above that level and three above 100.<br />
<br />
<span style="background-color: white;">The non-HDL numbers do look like noise at this point, except for the original cluster of low readings when the original butter experiment began. There probably was some underlying cause for that, though it is clear to me that if the butter had anything to do with it, the effect was temporary.</span></div>
<div style="text-align: -webkit-auto;">
<br />
<br />
Note also that there are several negative outliers for HDL in the non-Kerrygold butter set. This suggests that different brands of butter can have different effects on cholesterol measurements. This phenomenon may warrant further study.<br />
<br />
<h3>
What's the Take Away?</h3>
<br />
Okay, I hear what you're saying: "Greg, that's a heck of a lot of colored dots. So what?" I think the bottom line is, I'm eating a whole stick of butter every day and my lipid profile has either stayed the same or gotten a little better. Works for me.<br />
<br />
<h3>
<span style="background-color: white;">Measurement Accuracy</span></h3>
</div>
<br />
During this experiment, I observed that the <a href="http://cardiochek.com/index.php?option=com_content&view=article&id=169&Itemid=270">CardioChek PA</a> seems to be very accurate at measuring HDL, but much less accurate at measuring total (and therefore non-HDL) cholesterol. One of the newly collected data points shown above is the result of a VAP cholesterol panel ordered by my doctor. The same morning as the blood draw for that test, I took three successive readings of HDL and total cholesterol with the CardioChek PA. The VAP test showed an HDL of 68 and non-HDL of 233. The three HDL measurements on the CardioChek PA averaged out to 68, same as the VAP result, with a standard deviation of only 1.7%. For non-HDL, on the other hand, the average was 191 with a standard deviation of 15%. Compared to the 233 non-HDL measured by VAP, the CardioChek PA was off by 18% even when three separate measurements were averaged.<br />
<br />
Therefore, variance seen in my HDL readings over time suggests that real changes are taking place in my body. However, variance in my non-HDL measurements will be substantially the result of measurement error in addition to physiological changes. To put this in perspective, the standard deviation of all of my non-HDL measurements over the last 2+ years taken together is only 15.8%, barely higher than the meter's built-in measurement noise.<br />
<br />
The CardioChek also sells test strips for <a href="http://cardiochek.com/index.php?option=com_content&view=article&id=118&Itemid=229#LDL%20Cholesterol">direct LDL</a> measurement. I will probably check those out at some point, as they may prove to be more accurate than the total cholesterol strips.<br />
<br />
<h3>
Next Steps</h3>
Ideally, self-experimentation would be based on biomarkers that can be measured accurately and cheaply, and that quickly reflect real health trends. Blood sugar measurements are very useful in that regard, because it only takes one finger prick an hour after a meal to obtain useful information about your body's response to carbohydrates. <span style="background-color: white;">Over the course of this experiment, I've become skeptical of the value of cholesterol measurements as a target of self-experimentation. Given the meter's built-in measurement noise and the long half-life of circulating lipoproteins, it takes weeks or months for changes to be clearly evident. That makes it difficult to do useful experiments.</span><br />
<br />
My most pressing health goal until the end of 2012 is a <a href="http://www.youtube.com/watch?v=7OFjyEsk6Uo">405 pound deadlift</a>. High <a href="http://anthonycolpo.com/?p=3594">cholesterol</a> and extra calories from butter are probably going to help me achieve that goal, so I will be putting my cholesterol investigations on hold for the time being. In the mean time I do have a few other experiments to report on, so stay tuned.<br />
<br /></div>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com12tag:blogger.com,1999:blog-2658003869927046449.post-65764730834372164912012-05-15T21:43:00.000-04:002013-01-05T15:26:25.942-05:00A Case of Physics Envy?With the airing this week of the HBO obesity documentary "<a href="http://theweightofthenation.hbo.com/">The Weight of the Nation</a>," reporting on the obesity epidemic has reached a fever pitch. I wanted to take a break from my usual programming to mention an article I saw today in the New York Times entitled "<a href="http://www.nytimes.com/2012/05/15/science/a-mathematical-challenge-to-obesity.html">A Mathematical Challenge to Obesity</a>."<br />
<br />
Until now, mathematical hubris has been mostly the province of economic forecasters and financial risk modelers. As we have seen many times, if you do not fully understand the system that you are modeling, your <a href="http://www.zerohedge.com/news/james-montier-complexity-impress-monkeys-guns-and-why-var-doomed">model will be junk</a> even if you think it's the greatest thing in the world. Now it seems the modeling bug is looking to infect the nutrition field.<br />
<br />
The article is an interview with a mathematician who works for the National Institute of Diabetes and Digestive and Kidney Diseases, a division of NIH that I never knew existed. The mathematician, in an act of <a href="http://asociologist.com/2012/04/16/solow-on-physics-envy-qotd/">physics envy</a>, claims to have created a model of a human being based on a single equation. I thought I would just re-print the email I wrote to Claudia Dreifus, who is the Times writer who conducted the interview. Text in brackets are for context if you have not yet read the article (they were not in my email to Ms. Dreifus).<br />
<blockquote>
"I read your interview with Carson Chow and had a few questions. </blockquote>
<blockquote>
1. Mr. Carson claims to have proven that increased food availability "caused" the obesity epidemic. He says that if there is extra food, people eat more. Yet animals typically do not become obese under "ad libitum" conditions (i.e. unlimited food availability). Why are humans different and how does Mr. Carson's mathematical model "prove" that?</blockquote>
<blockquote>
2. How does he know the increase in food availability is a cause and not a result of the obesity epidemic? The alternative hypothesis is that people are hungrier than they were before, and since they want to eat more, the food system produces more.</blockquote>
<blockquote>
3. Why does Mr. Carson say that all diets work, when the clinical studies on diets almost invariably show that they don't work over the long term? If Mr. Carson has not done any experiments, how can his work prove that dieting works at all?</blockquote>
<blockquote class="tr_bq">
<i>[Carson Chow said "it's so easy for someone to go out and eat 6,000 calories a day."]</i></blockquote>
<blockquote>
4. Has Mr. Carson tried eating 6,000 calories a day for more than a couple of days? I don't think it is so easy, and professional bodybuilders and powerlifters often say that eating that much is the hardest part of their sport.</blockquote>
<blockquote>
5. I tried the <a href="http://bwsimulator.niddk.nih.gov/">bodyweight simulator</a> on the NIDDK site. Mr. Carson's mathematical model says that if I go from a very low carbohydrate diet to to a 6,000 calorie diet consisting of 100% carbohydrate, I would be able to gain hundreds of pounds within a week while maintaining a single-digit body fat percentage. While I agree that carbohydrates can cause weight gain for some people, that result is a little hard to swallow. Did the New York Times check the calculations to confirm they produced sensible results before interviewing Mr. Carson?"</blockquote>
<div>
I will update the blog if I get a response.</div>
<div>
<br /></div>
<div>
That last point is the most interesting to me. I believe the sports world will change forever once athletes realize they can gain nearly 750 pounds of lean mass in a week, without exercising. It is amazing nobody has taken advantage of this phenomenon before, and the first football team fielding multiple 900+ pound players is sure to be a favorite next season.</div>
<div>
<br /></div>
<div>
Here is a screenshot from the simulator showing this absurd result. The mistake probably stems from having "baseline calories from carbs" alone in a denominator somewhere (the app at least will not let you set this value to zero, so they caught that part of the bug).</div>
<div>
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-kYMmFRcD_GQ/T7MF9ibgo1I/AAAAAAAAAEM/cydA-lPTxWI/s1600/weight-simulator.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="490" src="http://4.bp.blogspot.com/-kYMmFRcD_GQ/T7MF9ibgo1I/AAAAAAAAAEM/cydA-lPTxWI/s640/weight-simulator.png" width="640" /></a></div>
<div>
<br /></div>
Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com0tag:blogger.com,1999:blog-2658003869927046449.post-58108775305401706162012-04-19T07:36:00.000-04:002012-04-19T07:36:22.895-04:00The Microbiome and Insulin SensitvityOne of the largest organs in your body is technically outside of your body. It is the microbiota in your intestines. It comprises 90% of your cells and 99% of your genes. This organ regulates, and is regulated by, your immune system, your digestion and metabolism, and it even makes a whole bunch of neurotransmitters. It is very complex and interesting. I am going to discuss one recent study which should introduce some of the experiments I will be writing about over the next couple of weeks. Thanks to "<a href="http://www.microbeworld.org/index.php?option=com_content&view=article&id=1168:twim-30-unraveling-melioidosis-and-insulin-resistance&catid=107:this-week-in-microbiology&Itemid=275">This Week in Microbiology</a>" (one of the best things on the entire Internet) for bringing this study to my attention.<br />
<br />
<a href="http://www.theatlantic.com/magazine/print/2010/11/lies-damned-lies-and-medical-science/8269/">John Ioannidis</a> has written about the fact that many of the results in the biomedical research literature have never been replicated. And when scientists do try to replicate prior results, they often get contradictory outcomes. Contradictory results are part of science, and they are a sign that new hypothesis need to be considered. This paper is a great example of that.<br />
<br />
The paper was published by Caricilli et. al. in December, 2011 in <a href="http://www.plosbiology.org/home.action">PLOS Biology</a> and is entitled "<a href="http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001212">Gut Microbiota is a Key Modulator of Insulin Resistance in TLR 2 Knockout Mice.</a>" The team of Brazilian scientists was working with mice that had been genetically modified to knock out the gene for toll-like receptor 2 (TLR 2), a component of the innate immune system. They found that these mice were insulin resistant and went on to develop a phenotype reminiscent of obesity and type 2 diabetes. This is in contrast to previous studies that showed the opposite effect in TLR 2 knockout mice. Same experiment, opposite result.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="http://1.bp.blogspot.com/-jTjQgLLc3ZA/T4qyysvNt-I/AAAAAAAAADg/2167vcAS4wE/s1600/TLR2-KO-1.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-jTjQgLLc3ZA/T4qyysvNt-I/AAAAAAAAADg/2167vcAS4wE/s1600/TLR2-KO-1.png" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 13px;">Three experiments from three labs. Conflicting results.</td></tr>
</tbody></table>
<br />
The Brazilian team came up with a new hypothesis that might be able to explain all of the results. They showed that the genetic modification to the mouse's innate immune system resulted in changes to the composition of the mouse's gut flora. They believe that the gut flora, in turn, altered the mouse's insulin sensitivity. The effect depends on the flora present in the local environment in which the mouse is raised. This would be expected to vary from one lab to another. Therefore, a TLR2 mouse's insulin sensitivity may go up in some labs and down in others. The Brazilian team was careful to ensure that the mice they were using were raised not just in the same lab, but in the same room. Now that's some careful science.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-91s9G-kwxBw/T4qzoj3g8DI/AAAAAAAAADo/Gam3P92vszc/s1600/TLR2-KO-2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-91s9G-kwxBw/T4qzoj3g8DI/AAAAAAAAADo/Gam3P92vszc/s1600/TLR2-KO-2.png" /></a></div>
<br />
<br />
The scientists characterized the gut flora of their control and TLR2 knockout mice (via sequencing 16S ribosomal RNA). They observed that firmicutes (a phylum of mostly gram-positive bacteria) are increased in their insulin resistant mice. When they transplanted this altered flora into healthy mice, they became insulin resistant too. When they used antibiotics which selectively kill off firmicutes in the TLR2 knockout mice, they went back to being insulin sensitive. Imagine that -- could we cure diabetes with antibiotics?<br />
<br />
If you've read this far, you might be curious about your own microflora. Simply ship your feces to <a href="http://www.metametrix.com/test-menu/profiles/gastrointestinal-function/dna-stool-analysis-gi-effects">Metametrix</a> and they'll analyze it by the same or a similar technique to that used in this paper. If you're insulin resistant, perhaps you have excess firmicutes and there may be strategies you can use to kick them to the curb. Of course mouse experiments do not necessarily translate to humans and healthy flora for a mouse will certainly differ from what is healthy in humans, but excess firmicutes have been found to be associated with obesity and diabetes in humans (in some but not all studies). Firmicutes have also been found to be reduced following <a href="http://www.pnas.org/content/106/7/2365.short">gastric bypass surgery</a>. A recent review paper by Tilg and Kaser (<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104783/pdf/JCI58109.pdf">Gut Microbiome, Obesity, and Metabolic Disfunction</a>) summarizes these findings. Of course, this information could turn out to be entirely useless -- perhaps it is not the categories of bacteria that matter, but specific strains, or the specific genes carried by (or expressed by) those strains. The interesting effects could depend not on what is there, but on the specific niches that particular strains have colonized (information that probably cannot be obtained from stool testing). We'll have to wait and see as this work is elaborated with new research, including the results of the <a href="http://commonfund.nih.gov/hmp/">Human Microbiome Project</a>.<br />
<br />
<h3>
Is your Microbiome a Gland?</h3>
<br />
I mentioned above that the microbiome is in constant communication with your immune system and metabolic regulatory pathways. We saw from the Caricilli paper that changes in the microbiome can alter insulin sensitivity. One of the signaling molecules involved in this communication is lipopolysaccharide, or LPS. This is a component of the cell walls of gram negative bacteria. Your immune system is exquisitely sensitive to it. Concentrations measured in picograms per milliliter can cause measurable effects. This is a bit frightening when you realize that each of us is carrying around many grams (that's trillions of picograms) of LPS in our normal gut flora. Too much LPS and you die of sepsis, even if no live bacteria are present. Your immune system will kill you. For this reason, LPS has been referred to as bacterial endotoxin, though recent findings suggest it is much more than a mere toxin.<br />
<br />
One very intriguing theory has been presented by John Marshall in a <a href="http://cid.oxfordjournals.org/content/41/Supplement_7/S470.full.pdf">paper in Clinical Infectious Diseases</a> (2005). He suggested that LPS should be thought of primarily not as a toxin, but as a hormone. It bears many similarities to our more familiar hormones. It exerts systemic effects by binding to specific receptors in multiple target tissues, triggering gene expression. It's effects are tightly regulated by a specific binding protein (creatively named "LPS binding protein") and multiple negative feedback loops. Typical of other hormones, it is harmful in excess, but beneficial in the right quantity and the right context. Of course it is quite odd for a hormone to be produced outside of your body, but in other respects it might fit the mold.<br />
<br />
LPS typically spikes after meals, and has an acute systemic inflammatory effect. Going back to the mouse study, Caricilli et. al. found that their TLR2 knockout mice had higher serum LPS levels than the controls, and a greater increase in serum LPS following oral ingestion. The higher spike in LPS could be explained by the fact that the TLR2 knockout mice had lower levels of a tight junction protein that helps maintain gut barrier integrity. So it looks like an altered immune system resulted in an altered microbiome which changed intestinal barrier integrity which increased exposure to an exogenous hormone resulting in systemic inflammation, which caused metabolic dysfunction insulin resistance and obesity. Or, since the paper did not clearly establish cause and effect, any of the foregoing in any other causal permutation. Ok!<br />
<br />
There is a lot more to say about LPS. What sorts of things cause it to increase, chronically or acutely? What regulates the body's response to it? And what about those curious negative feedback loops? More importantly, can we observe its effects through self-experimentation? Stay tuned for more.<br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com2tag:blogger.com,1999:blog-2658003869927046449.post-20010484262703418162012-04-19T00:03:00.001-04:002013-01-05T15:30:55.687-05:00Follow Up on ButterWelcome readers. I wanted to post some follow up details on my experiments so far and say a bit more about the themes I will be writing more about. You'll notice that my headlines so far have been phrased as questions. This is not an homage to a <a href="http://www.jeopardy.com/">popular quiz show</a> -- they are questions because I don't know the answers. So with that in mind I wanted to revisit the results of my first experiment (<a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">Is Butter as Powerful as a Statin?</a>).<br />
<br />
Science is hard, and if you attempt it, you need to stay vigilant about not fooling yourself, because, <a href="http://calteches.library.caltech.edu/3043/1/CargoCult.pdf">as Richard Feynman has said</a>, you're the easiest person to fool. So I'll be reviewing my initial results to see whether I've fooled myself. Of course when it comes to personal science, we should always be aware of this principle in reviewing work done by others. If someone has managed to fool himself (even for a moment), perhaps they might fool you too. I hope my readers will keep this in mind.<br />
<br />
Commenter <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html?showComment=1333770140078#c64465849228859938">EricT</a> highlighted the biggest weakness in my <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">butter experiment</a>. I originally added the butter to my diet to see what sorts of subjective effects it might have (they were positive, but I did not track anything quantitative that I can present). I tracked my lipids at the time only in order to monitor whether they might move in an adverse direction. It looked like the Kerrygold butter caused beneficial changes while other brands did not. I therefore changed my hypothesis mid-stream, which is a substantial source of bias, effectively rendering my statistical analysis invalid (this particular weakness is not applicable to the second experiment on <a href="http://kneelessmegafauna.blogspot.com/2012/04/do-carbs-lower-hdl.html">safe starches vs. HDL</a>, though of course other weaknesses do apply). Meanwhile I am continuing the butter experiment and will present all additional data points in a couple of weeks so we can see whether the effect holds. In the mean time, by then I will have data from another VAP cholesterol test so I can have more confidence about what my CardioChek meter is actually measuring and how consistent it is. Stay tuned for that. Meanwhile I have declared a "grain of salt" advisory on the butter post.<br />
<br />
If the additional data points do not show a continuation of the effect seen previously, it would weigh strongly against the hypothesis that butter causes beneficial changes in lipids (though this is somewhat independent to the question of whether butter is good or bad from a cardiovascular perspective). Many alternative hypotheses could explain a negative outcome -- the effect could have been the result of the bias, a short-lived disruption of homeostasis, a systematic user error or environmental sensitivity with the CardioChek device, or an unknown and temporary cause coinciding in time with the applicable data points. Since I did not decide beforehand how long my experiment would last, the effect could also have been a statistical anomaly which only seemed "significant" because of the particular day on which I decided to compile my results (that is, you can't just wait until you get the result you want and choose that as the date on which to <a href="http://abcnews.go.com/Health/HeartHealth/cholesterol-busting-statins-study-raises-concerns/story?id=11037926&page=2#.T4m2xppSS3Y">terminate your study</a>).<br />
<br />
In the mean time, I've been measuring another health marker that is related to gut health and the microbiome. I am going to write about about that and then present some interesting and hopefully useful data over the next few weeks.<br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com0tag:blogger.com,1999:blog-2658003869927046449.post-48281759832357302642012-04-01T21:25:00.000-04:002013-01-05T15:31:16.194-05:00Do Carbs Lower HDL?<h3>
Attack of the Safe Starches</h3>
<br />
If you have been lurking around paleoland recently you will have heard the debate about <a href="http://livinlavidalowcarb.com/blog/is-there-any-such-thing-as-safe-starches-on-a-low-carb-diet/11809">safe starches</a> (you may be sick of hearing about it in fact). Last fall I ran an experiment to find out whether it might be a good idea to dip my toe into the safe starch swimming pool. I was tracking my lipids around this time with the <a href="http://cardiochek.com/index.php?option=com_content&view=article&id=169&Itemid=270">CardioChek PA</a> so I could have some idea of what was going on with my metabolism. Here are the results.<br />
<br />
I first experimented with a low carbohydrate diet in 2009 after reading <a href="http://garytaubes.com/works/books/good-calories-bad-calories/">Good Calories, Bad Calories</a> by Gary Taubes. I lost 15 pounds in the first three months (though I had no idea I was carrying any extra fat). I gained muscle without changing my exercise program. My seasonal allergies went away. My teeth got whiter, less sensitive and stopped collecting plaque. I got fewer sunburns. My joints stopped aching after exercise. You get the idea.<br />
<br />
Around this time I took an oral glucose tolerance test and found my numbers to be a bit high, though not in the pre-diabetic range just yet. I tend to get a high initial blood sugar spike, though the value quickly returns to normal. I thought this (along with the other general health improvements I experienced) was an indicator that a low carb diet was a good approach for me. I bought a cheap glucometer to play with and stuck with the low carb program.<br />
<br />
Over the years my diet progressed to a paleo approach, while I continued to avoid starches. On most days I ate only eggs, meat, fish, some nuts and a good helping of green veggies. Given the safe starches controversy, I thought it would be interesting to try adding 100g or so of carbs per day in the form of sweet potatoes, just to see what would happen. There is a variety of chatter about the possibility that low carbohydrate diets <a href="http://perfecthealthdiet.com/?p=4457">can raise LDL</a>, so I thought I might see a drop in non-HDL cholesterol with a bit of added starches. I did get a drop, but it wasn't to the non-HDL.<br />
<br />
<h3>
Results</h3>
<br />
Mean non-HDL did not change during the experiment (193 to 203, not statistically significant), but mean HDL dropped by a significant amount (67 to 57, p<0.001). I stopped the experiment after one month. You'll see in the plot below that the HDL went back up to the previous level after the daily sweet potato was dropped.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-VCaVyj6FDk8/T3ZpbUuUxRI/AAAAAAAAADI/j3JQT-pHsr8/s1600/hdl-boxplot.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-VCaVyj6FDk8/T3ZpbUuUxRI/AAAAAAAAADI/j3JQT-pHsr8/s1600/hdl-boxplot.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Boxplots show minimum, maximum and quintiles. Mean HDL: 67 (control), 57 (carbs).</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-4J-ZzYrdvM4/T3Zpb7C9ltI/AAAAAAAAADQ/ZDNrh12Ub1Y/s1600/hdl-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-4J-ZzYrdvM4/T3Zpb7C9ltI/AAAAAAAAADQ/ZDNrh12Ub1Y/s1600/hdl-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The trendline is a linear model based on all low carb data points (before and after, but not including, the carb intervention).</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-pFJbLO9OW5k/T3jyikkhqXI/AAAAAAAAADY/ApEqnhZFIeY/s1600/nonhdl-trend.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://1.bp.blogspot.com/-pFJbLO9OW5k/T3jyikkhqXI/AAAAAAAAADY/ApEqnhZFIeY/s1600/nonhdl-trend.jpeg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Trendline based on all low-carb points. Non-HDL cholesterol was not significantly affected.</td></tr>
</tbody></table>
<br />
<h3>
Details of the Experiment</h3>
The data points were collected as previously discussed in the <a href="http://kneelessmegafauna.blogspot.com/2012/03/is-butter-as-powerful-as-statin.html">butter experiment</a>. Data does not include any points during the butter experiment, as there was a significant change in HDL and non-HDL during that time. Statistical significance test is based on a linear model, calculated by ANOVA using <a href="http://www.r-project.org/">R</a>.<br />
<br />
Sweet potatoes were eaten slowly so as not to spike blood sugar above 120, though spikes may have occurred on occasion. It usually takes me about an hour to eat one, though I can eat them very fast without a spike if I've recently completed a heavy workout.<br />
<br />
There are a number of limitations to the interpretation of this data that are worth mentioning. Perhaps most significantly, this is a very short term test (1 month). It is possible that long term adaptations would have reversed the effects seen here. Second, there was only a single intervention period, which could have corresponded to another unknown variable which caused HDL to decrease. Since foods differ in micronutrient, mineral and toxin content, it is not possible to generalize from sweet potatoes to all carbohydrates. I may have had a different result with white rice, white potatoes, taro, tapioca, etc. Finally, of course this result applies to me only. There may be others who have a much higher carbohydrate tolerance, or who may even see the opposite result.<br />
<br />
<h3>
Is This Actionable Information?</h3>
<br />
So why am I bothering with this? First of all, simple curiosity. I have the ability to collect data that most people do not collect, and there is some interesting science concerning these molecules and what they may be able to tell me about my metabolism.<br />
<br />
Does the decrease in HDL identified here represent an unhealthy change? Perhaps. Though HDL is commonly referred to as the "good cholesterol", I would not suggest that all decreases in HDL are unhealthy. In fact I don't know how one would go about establishing the truth or falsehood of a statement like that. Conversely, we know of <a href="http://en.wikipedia.org/wiki/Torcetrapib">chemicals</a> that raise HDL while simultaneously causing heart attacks. My HDL was never "low" during the course of this experiment. However, together with certain other data I was also collecting at this time (which is a story for another day), I believe that 100 grams of starch per day is too much for me. At least in my current metabolic state, with my current lifestyle, exercise habits, sleep, stress level, etc.<br />
<br />
Some smaller amount of starch is most likely "safe," and may be a good idea. These days I often eat a banana (about 20-30 grams of sugar+starch) after lunch, and I have not seen the negative effects caused in me by higher amounts of carbohydrate. As mentioned, I also have found that I can eat 100 grams of carbs immediately after a heavy workout with no significant change in my blood sugar (e.g. it might increase from 65 to 83 in response to a pound of sweet potatoes after two hours of powerlifting). These days, workouts like that occur about once a week (sometimes less), and I have not noticed any negative effects from eating carbs this infrequently. Since many smart (and strong) people advocate carbs post-workout, I am willing to go along for now, at least while I do not have any contradictory evidence.<br />
<br />
<h3>
Published Research</h3>
<br />
Perhaps if I had looked this stuff up in the scientific literature first I would have been less surprised by my results. It turns out there is plenty of published research supporting the idea that carbs lower HDL. However, it is a bit surprising that the relationship continues even below 100g/day. I doubt there is published research on this relevant to long-term low carbers, so three cheers for personal science on that front. A study by a German team, published in January 2012 in the Annals of Nutrition and Metabolism, does a good job summing up the research that is out there. Here is their conclusion regarding carbohydrates and HDL:<br />
<br />
<blockquote class="tr_bq">
<i>"There is convincing evidence that a higher carbohydrate proportion in the diet at the expense of total fat or saturated fatty acids intake lowers the plasma concentration of HDL cholesterol."</i></blockquote>
<br />
The paper is called "<a href="http://content.karger.com/produktedb/produkte.asp?DOI=000335326&typ=pdf">Evidence-Based Guideline of the German Nutrition Society: Carbohydrate Intake and Prevention of Nutrition-Related Disease</a>." It is worth a read if you are interested and still awake. If instead you are sleeping (and not German), perhaps you are dreaming of a world in which the nutrition organizations in your country also use evidence as the basis for their guidelines.<br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com5tag:blogger.com,1999:blog-2658003869927046449.post-77464446948542257942012-03-28T21:35:00.000-04:002013-01-05T15:31:26.352-05:00Is Butter As Powerful as a Statin?<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-sE4x11HD9T0/T44oVmJzVBI/AAAAAAAAADw/FFV_-uesbxs/s1600/grainofsalt.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-sE4x11HD9T0/T44oVmJzVBI/AAAAAAAAADw/FFV_-uesbxs/s1600/grainofsalt.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Notice: A Grain of Salt Advisory is in effect for this post. See comments and this <a href="http://kneelessmegafauna.blogspot.com/2012/04/follow-up-on-butter.html">new post</a> for details. <a href="http://kneelessmegafauna.blogspot.com/2012/07/butter-not-like-statin-after-all.html">Subsequent data collection</a> has changed the conclusions presented below.</td></tr>
</tbody></table>
<span style="font-family: inherit;">Butter is an interesting food. For those who have graduated from an un-scientific fear of fat, it would seem to encapsulate almost everything that is good about cow's milk, with only small amounts of the questionable stuff (lactose and milk proteins). What's not to like? Certainly some very sensitive people could respond negatively to the trace sugars and proteins in butter, but for most people it seems like it should qualify as a health food.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Health professionals are usually quick to warn us away from butter because it is high in <a href="http://www.marksdailyapple.com/saturated-fat-healthy/">artery-clogging-saturated-fat</a>. The old story goes that butter is bad for you because saturated fat raises cholesterol, and elevated cholesterol causes heart disease. I can't do an n=1 experiment on the effects of butter on mortality but with a home cholesterol meter it is easy to find out whether the first part of the old story is true. Does butter actually raise blood cholesterol levels? Whether that has anything to do with heart disease is a story for another day (I happen to believe there may be a small relationship between cholesterol and heart disease for some people, but it's complicated).</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">In fact, eating half a stick of butter a day significantly lowered my cholesterol. It lowered it about as much as the reported effects of many <a href="http://en.wikipedia.org/wiki/Statin">statins</a> (sorry, haven't tried the statins so you'll have to trust the clinical trials on those). Read on for the details, but first a few words about butter.</span><br />
<span style="font-family: inherit;"><br /></span>
<h3>
<span style="font-family: inherit;">
What color is it?</span></h3>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">These days, most consumers expect butter to be white and margarine to be a pleasing yellow. Never mind the fact that margarine was originally colored yellow in order to make it look like healthy grass-fed butter. For years, many states had laws prohibiting the sale of artificially colored margarine. Housewives were sometimes sold <a href="http://www.thefreemanonline.org/featured/the-war-on-margarine/">a small packet of food coloring</a> with each tub so they could trick their families into thinking they were eating something that was good for them.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Butter with a high vitamin content is yellow, not white. Unfortunately, artificially colored butter is also yellow. In fact, butter and cheese were the first foods the U.S. federal government allowed to be <a href="http://www.fda.gov/ForIndustry/ColorAdditives/RegulatoryProcessHistoricalPerspectives/default.htm">artificially colored</a>. This gave butter producers a leg up in competing against margarine, where artificial colors were usually not allowed. For most foods, added colors need to be identified on the label and/or ingredients list. Butter is exempt from this requirement (see <a href="http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.22">Section 101.22(k)(3)</a> of Title 21 of the U.S. Code of Federal Regulations). Therefore, do not judge American butter by its color.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">The best butter is made from milk produced by cows that live outside and eat their natural diet, grass. The "organic" label can be applied to corn-fed cows raised in feedlots. Therefore, the term doesn't really tell you anything useful about the quality of butter. It is about as useful as calling farmed fish "organic." Personally I don't pay any attention to that label when it comes to butter and I look for butter that I am confident comes from cows that live outside and eat only grass.</span><br />
<span style="font-family: inherit;"><br /></span>
<h3>
<span style="font-family: inherit;">Butter throughout History</span></h3>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Anthimus, an exiled Byzantine doctor writing in northern Gaul in the 6th century, <a href="http://books.google.com/books?id=FtIXAe2qYDgC&pg=PA65&lpg=PA65&dq=butter&source=bl&ots=20ZWK92vZg&sig=1_Pwc3vPpdEnzZJvlMHRn4gqh9M&hl=en&sa=X&ei=LGJvT-_UGIXn0QGwrfXdBg&ved=0CB8Q6AEwAA#v=onepage&q=butter&f=false">recommended</a> butter with honey to patients suffering from tuberculosis. This is interesting because, for many years prior to the introduction of antibiotics, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC313186/">cod liver oil</a> (which, like grass fed butter, is rich in vitamin A) was the standard of care for tuberculosis treatment.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">The dentist Weston A. Price found butter to be a <a href="http://www.westonaprice.org/food-features/why-butter-is-better">staple food</a> in many healthy populations around the world.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">According to MS Iceland Dairies, which produces the <a href="http://www.smjor.is/Butter-in-Iceland/">Smjor</a> brand of butter, the Icelandic people prized butter as an important and healthy food.</span><br />
<blockquote class="tr_bq">
<span style="font-family: inherit;">"People usually had considerable stores of butter; it was used extensively, and it was considered a source of strength during the harsh winter months when people needed to consume a lot of fat. The recommended portion was approximately 1700g a week per person."</span></blockquote>
<span style="font-family: inherit;">For the Americans in the audience: 1700 grams of butter is over 3.7 pounds. Per week.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Butter seems to be especially valued in cold climates, perhaps because it could be stored prior to refrigeration without going too far rancid. For example, see Tibet and their famous <a href="http://chowhound.chow.com/topics/334708">rancid yak butter</a> tea.</span><br />
<span style="font-family: inherit;"><br /></span>
<h3>
<span style="font-family: inherit;">Cholesterol for Breakfast</span></h3>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">As I mentioned above, I don't believe there is a strong relationship between blood cholesterol levels and heart disease risk. In addition, if there is a relationship between blood cholesterol levels and total mortality, it appears to be non-linear and probably <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2753.2011.01767.x/pdf">U-shaped</a>, with increased mortality when levels are too high or too low. That said, my cholesterol has been a bit higher than I'd like over the last 10 years or so, and I've tried on and off to see if there is a reasonable way to change it without doing something crazy like eating <a href="http://www.metamucil.com/">laxatives</a> or <a href="http://lipidlibrary.aocs.org/lipids/plant_st/index.htm">plant hormones</a>. Over the past year I've been monitoring my blood lipids from time to time with a <a href="http://www.cardiochek.com/">CardioChek</a> meter and paying attention to what causes the numbers to change. Most of the data for this experiment comes from the CardioChek machine, though some readings are lab tests ordered by my doctor.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Notwithstanding the <a href="http://www.ncbi.nlm.nih.gov/pubmed/22037012">absence</a> of supporting evidence, the <a href="http://fnic.nal.usda.gov/nal_display/index.php?info_center=4&tax_level=2&tax_subject=256&topic_id=1332">2010 Dietary Guidelines for Americans</a> recommend that humans consume no more than 300 mg of cholesterol per day. Now a few times in the past two years I have substantially varied my egg intake, and therefore my total dietary cholesterol. Although I don't have enough readings to get good statistics on these changes, my observation is consistent with the published scientific literature. There is no association between dietary cholesterol, per se, and my blood cholesterol. My cholesterol generally stays the same or perhaps drops a little when I eat more eggs (e.g. going from no egg consumption to 4 per day). There may be some subset of the population that is sensitive to dietary cholesterol, but I do not seem to fall into that category.</span><br />
<span style="font-family: inherit;"><br /></span>
<h3>
<span style="font-family: inherit;">The Thousand Calorie Omelete</span></h3>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">This story is not about eggs or dietary cholesterol. It is about what happened to me when I added a large amount of butter to my breakfast. In January I added half a stick of butter (about 57 grams) to my morning omelete. I first got this idea from <a href="http://blog.sethroberts.net/">Seth Roberts</a>, who reportedly has been eating half a stick of butter per day for some time in order to increase his mental performance. Seth believes butter has been good for his heart. <a href="http://www.bulletproofexec.com/how-to-make-your-coffee-bulletproof-and-your-morning-too/">Dave Asprey</a> also recommends eating lots of butter for brain health, among other reasons. My omelete consists of four pastured eggs, half a stick of <a href="http://www.kerrygold.com/">Kerrygold</a> Irish butter, and three tablespoons of coconut oil. Thats 1,076 calories, 110 grams of fat (75 grams from saturated fat) and 865mg of cholesterol. My diet otherwise stayed <a href="http://3.bp.blogspot.com/-rTj3ZgtUIWE/TegFX8RRQAI/AAAAAAAAANE/z8nBOl3Gnu8/s1600/notthathardpeople.jpg">the same</a>, though I was usually eating smaller portions of everything else.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">The effect this had on my blood cholesterol was significant enough to inspire me to finally start a blog. Of all the interventions I've tried over the years, this has been by far the most powerful and the first one to show up clearly after the first couple of data points.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Here are the results. On average: HDL is up 19%, non-HDL is down 25%. Both results are statistically significant with high confidence levels, despite relatively small sample sizes (p<.001 and .01 respectively). Here are some boxplots to make it more convincing. The plots show min, max, mean, and the 1st and 3rd quintiles.</span><br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-CNpEsxgJzj0/T2-vtiWTlBI/AAAAAAAAAB4/fqadcnpKwMo/s1600/hdl.jpeg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: inherit;"><img border="0" src="http://2.bp.blogspot.com/-CNpEsxgJzj0/T2-vtiWTlBI/AAAAAAAAAB4/fqadcnpKwMo/s1600/hdl.jpeg" /></span></a></div>
<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-qstNjRfvX5E/T2-vt_ju4tI/AAAAAAAAACA/ulX9qP4DB7k/s1600/nonhdl.jpeg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><span style="font-family: inherit;"><img border="0" src="http://1.bp.blogspot.com/-qstNjRfvX5E/T2-vt_ju4tI/AAAAAAAAACA/ulX9qP4DB7k/s1600/nonhdl.jpeg" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: inherit;">Boxplots showing min, max, mean and quartiles.<br />Mean HDL (control, treatment, change): 65, 77, +19%.<br />Mean non-HDL (control, treatment, change): 196, 148, -25%</span></td></tr>
</tbody></table>
<h3>
</h3>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
The following plots show my pre-butter trends for HDL and non-HDL in red, with the post-butter readings in blue (thanks Seth for the suggestion). This suggests that the new readings do not reflect the continuation of a pre-existing trend. I did not add trendlines for the post-butter readings because there are not enough datapoints for them to make sense. Note that 5 of the 6 post-butter HDL readings are the highest ever recorded. 4 of the 6 non-HDL readings are the lowest ever recorded.<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-zHfupRPbx3M/T3JWgn69sJI/AAAAAAAAAC4/xYpBEr810pA/s1600/hdl-trend.jpeg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-zHfupRPbx3M/T3JWgn69sJI/AAAAAAAAAC4/xYpBEr810pA/s1600/hdl-trend.jpeg" /></a></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-8I5Zgxk0zS8/T3JWhWAfh8I/AAAAAAAAADA/k0gWTFu92xM/s1600/nonhdl-trend.jpeg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="http://3.bp.blogspot.com/-8I5Zgxk0zS8/T3JWhWAfh8I/AAAAAAAAADA/k0gWTFu92xM/s1600/nonhdl-trend.jpeg" /></a></div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<h3>
What's the Best Butter?</h3>
<br />
When I was growing up, I was quite a picky eater, and was very specific about the brands of butter that I would allow my parents to bring into the house. Most brands tasted downright rancid. Even still, I don't think I ever tasted good butter until I was well into my adult years. The bad stuf is not worth eating, and I now have a bit of experimental evidence to back that up.<span style="font-family: inherit;"><br /></span><br />
<br />
My butter of choice is <a href="http://www.kerrygold.com/">Kerrygold</a> from Ireland. While Kerrygold seems to be somewhat coy about saying "100% grass fed" in its marketing materials, it is pretty consistently cited as the best butter that is readily available around the U.S. <a href="http://www.traderjoes.com/">Trader Joe's</a> almost always has the best prices in my vicinity. During the course of this experiment, I tried two other types of butter. One was <a href="http://www.smjor.is/Products/Smjor-unsalted/">Smjor</a>, mentioned above. The other was a "grass fed" butter from my local farmers' market. The Smjor was delicious and very yellow, so it looked like a good pick. The local butter was white and not especially appetizing, perhaps understandable for cows living in New York in the winter and necessarily given some kind of supplemental feed. The cholesterol readings I was getting from the Smjor and local butter were all over the map and were not consistent with the numbers I got with the Kerrygold. Therefore I did what <a href="http://www.youtube.com/watch?v=v8WA5wcaHp4">any good scientist</a> would have done and threw those data points away so I could present results only for thousand calorie omeletes made with Kerrygold.<br />
<br />
<br />
<h3>
<span style="font-family: inherit;">Details of the Experiment</span></h3>
<br />
<span style="font-family: inherit;">There are 6 measurements in the experimental (butter) group and 16 in the control (non-butter) group. Additional measurements taken within 1 week were not used. The butter group includes all measurements made when I had been eating at least 1/2 stick (about 56 grams) of Kerrygold butter per day for at least a week prior to measurement. Datapoints when I was consuming other brands of butter were not included. The first five measurements were VAP cholesterol tests ordered by my doctor. Otherwise, I measured total cholesterol and HDL cholesterol in a single panel with a </span><a href="http://www.testsymptomsathome.com/pol91_cardiochek_pa_test_strips.asp" style="font-family: inherit;">CardioChek PA</a><span style="font-family: inherit;">. I did not measure LDL directly, and I did not calculate it because my fasting triglycerides are not measurable with my meter (<50). Besides, the LDL calculation formulas are </span><a href="http://www.proteinpower.com/drmike/weight-loss/low-carbohydrate-diets-increase-ldl-debunking-the-myth/" style="font-family: inherit;">nonsense at best</a><span style="font-family: inherit;"> when triglycerides are under 100. I use non-HDL as a rough estimate of the atherogenic potential of blood lipids (basically a crude proxy for </span><a href="http://www.ncbi.nlm.nih.gov/pubmed/20827192" style="font-family: inherit;">apolipoprotein B</a><span style="font-family: inherit;">).</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">The increase in HDL and decrease in non-HDL were both statistically significant as determined by ANOVA using <a href="http://www.r-project.org/">R</a> (p<.001 and .01 respectively). However, I should point out that, for a variety of reasons, these are not high quality statistics. First of all, I have no formal training in statistics. Given that some data points were taken fairly close together in time, there is likely some serial correlation between measurements. I also made no particular effort to control for other variables. Finally, these results apply to me. There may well be people who respond differently and for whom butter is unhealthy. As with anything, it is always advisable to test things for yourself. So take this with a grain of salt. Or half a stick of butter, if you prefer.</span><br />
<br />Greghttp://www.blogger.com/profile/00966592489321207595noreply@blogger.com12