Animal fats are good for you

Nutrition advice is usually based on weak evidence or no evidence. In some cases, the evidence points to the opposite of the expert advice. Here is such an example, and the embarrassing study with the best science behind it was not even published for 40 years.

SciAm reports:

Ramsden, of the National Institutes of Health, unearthed raw data from a 40-year-old study, which challenges the dogma that eating vegetable fats instead of animal fats is good for the heart. The study, the largest gold-standard experiment testing that idea, found the opposite, Ramsden and his colleagues reported on Tuesday in BMJ (formerly the British Medical Journal).

Although the study is more than just another entry in the long-running nutrition wars—it is more rigorous than the vast majority of research on the topic—Ramsden makes no claims that it settles the question. Instead, he said, his discovery and analysis of long-lost data underline how the failure to publish the results of clinical trials can undermine truth.

Absent a time machine, it’s impossible to know how publication of the study, conducted in Minnesota from 1968 to 1973, might have influenced dietary advice. But in an accompanying editorial, Lennert Veerman of Australia’s University of Queensland concluded that “the benefits of choosing polyunsaturated fat over saturated fat seem a little less certain than we thought.”