|Notice: A Grain of Salt Advisory is in effect for this post. See comments and this new post for details. Subsequent data collection has changed the conclusions presented below.|
Health professionals are usually quick to warn us away from butter because it is high in artery-clogging-saturated-fat. 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).
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 statins (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.
What color is it?
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 small packet of food coloring with each tub so they could trick their families into thinking they were eating something that was good for them.
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 artificially colored. 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 Section 101.22(k)(3) of Title 21 of the U.S. Code of Federal Regulations). Therefore, do not judge American butter by its color.
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.
Butter throughout History
Anthimus, an exiled Byzantine doctor writing in northern Gaul in the 6th century, recommended butter with honey to patients suffering from tuberculosis. This is interesting because, for many years prior to the introduction of antibiotics, cod liver oil (which, like grass fed butter, is rich in vitamin A) was the standard of care for tuberculosis treatment.
The dentist Weston A. Price found butter to be a staple food in many healthy populations around the world.
According to MS Iceland Dairies, which produces the Smjor brand of butter, the Icelandic people prized butter as an important and healthy food.
"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."For the Americans in the audience: 1700 grams of butter is over 3.7 pounds. Per week.
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 rancid yak butter tea.
Cholesterol for Breakfast
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 U-shaped, 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 laxatives or plant hormones. Over the past year I've been monitoring my blood lipids from time to time with a CardioChek 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.
Notwithstanding the absence of supporting evidence, the 2010 Dietary Guidelines for Americans 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.
The Thousand Calorie Omelete
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 Seth Roberts, 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. Dave Asprey also recommends eating lots of butter for brain health, among other reasons. My omelete consists of four pastured eggs, half a stick of Kerrygold 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 the same, though I was usually eating smaller portions of everything else.
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.
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.
|Boxplots showing min, max, mean and quartiles.|
Mean HDL (control, treatment, change): 65, 77, +19%.
Mean non-HDL (control, treatment, change): 196, 148, -25%
What's the Best Butter?
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.
My butter of choice is Kerrygold 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. Trader Joe's almost always has the best prices in my vicinity. During the course of this experiment, I tried two other types of butter. One was Smjor, 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 any good scientist would have done and threw those data points away so I could present results only for thousand calorie omeletes made with Kerrygold.
Details of the Experiment
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 CardioChek PA. 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 nonsense at best 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 apolipoprotein B).
The increase in HDL and decrease in non-HDL were both statistically significant as determined by ANOVA using R (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.