The most common myth about saturated fat is that it causes cardiovascular disease. This myth is still pushed by organizations such as the American Heart Association. But is it true? Let’s take a look.
The theory that saturated fat may cause cardiovascular disease was popularized by a man named Ancel Keys. Despite the fact that many people who have seen through the saturated fat myth now like to demonize Keys, it turns out that Keys wasn’t such a bad guy.
He made many important contributions to our knowledge of human nutrition, and it turns out that his hypothesis was actually founded on good data. The data he collected really did demonstrate a positive correlation between saturated fat intake and cardiovascular disease.
The trouble with the conclusion Keys drew is multifaceted. Denise Minger has written a lovely article in which she pulls apart the problems with the conclusion, relying heavily on a critique written in 1957 by two men named Yerushalmy and Hilleboe (Yerushalmy & Hillboe, 1957).
They point out that while countries with higher levels of saturated fat available have higher rates of reported cardiovascular disease, overall they have considerably lower rates of disease when compared to countries with lower levels of saturated fat available.
They also point out that higher levels of saturated fat correlate with wealth in the data. And they go on to suggest that less wealthy countries were likely grossly under-reporting cardiovascular disease deaths, instead classifying them as something else.
The real wrench in the works, however, is that the data Keys was working from was simply a report of what food existed in a country. He wasn’t looking at what people actually were eating. So at the end of the day, although Keys’ graphs may be interesting, they didn’t tell us anything about real world trends.
Subsequent to Keys’ publication, he landed a position on the board of the American Heart Association, and only then did the recommendation to limit dietary saturated fat intake start making its way into mainstream channels. Since then, there’s been a steady stream of propaganda warning us to eat less saturated fat. But is this suggestion backed up by good science?
Nope. It’s not. And now the evidence is mounting that saturated fat is not a problem. In 2010, a massive meta-analysis project looked at nearly 350,000 subjects and concluded that “there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD [stroke] or CVD [cardiovascular disease].” (Siri-Tarino, Sun, Hu, & Krauss, 2010)
A former president of the American College of Cardiology and former advocate of the saturated fat myth is now quoted as saying, “The low-fat, high-carbohydrate diet may well have played an unintended role in the current epidemics of obesity, lipid abnormalities, type 2 diabetes, and metabolic syndromes.
This diet can no longer be defended by appeal to the authority of prestigious medical organizations.” (Weinberg, 2004) And a recent publication in Annals of Internal Medicine performed a meta-analysis of an even larger group of people and concluded that “current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.” (Chowdhury, et al., 2014)
Chris Masterjohn put together an excellent analysis of the only high-quality human studies that have been done looking at saturated fat and cardiovascular disease, and he showed that those studies demonstrated absolutely no link at all.
In fact, in the L.A. Veteran’s Trial, the evidence was that the saturated fat group had fewer overall deaths (from all causes) despite the fact that the saturated fat group had more heavy smokers (a known health risk) and that the study design accidentally made the saturated fat group deficient in vitamin E (also a known risk). So all things considered, it would even be reasonable to consider the possibility that saturated fat could be protective.
Despite the diehards who are clinging to a sinking ship, the saturated fat causes cardiovascular disease myth has lost credibility. There does not appear to be any cardiovascular risk associated with natural saturated fat intake from real foods.
And, some saturated fat sources such as butter contain important fat-soluble nutrients as well as other factors (like conjugated linoleic acid) that are shown to be protective against a variety of conditions, including cancer.