An international group of nutrition and cardiovascular (CVD) experts risk re-assessed a variety of prior large studies, which originally sought a link between dietary consumption of saturated fats and CVD risk. The group, led by Dr. Rajiv Chowdhury of UK s Cambridge University (along with experts from Harvard School of Public Health and Oxford University) collected data from 76 studies which included 659,000 subjects. Some of the studies were observational only, using dietary recall data, while others were interventional: prospective and randomized. Some of the studies assessed what people reportedly ate, while some measured fatty acid levels in their blood; all reported CVD outcomes. The study appeared in the current Annals of Internal Medicine.
Their surprising overall finding was a lack of relationship between any specific type of saturated fat, or for the totality of saturated fat intake, and CVD risk. The only exception: a slightly increased risk, about 16 percent, for intake of trans-fatty acids (trans-fats). Further, there was no evidence of a protective effect for consumption of those types of fats thought to possibly lower CVD risk, specifically omega-3 fatty acids, most often obtained from fish although there was a suggestion of reduced risk if the levels of omega-3s were higher in the bloodstream.
How is the typical consumer supposed to interpret these counter-intuitive findings? Experts discussing this very point with the N.Y.Times Anahad O Connor had somewhat differing recommendations:
My take on this would be that it s not saturated fat that we should worry about in our diets, said the lead author, Dr. Rajiv Chowdhury. But Dr. Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health, said the findings should not be taken as a green light to eat more steak, butter and other foods rich in saturated fat. He said that looking at individual fats and other nutrient groups in isolation could be misleading, because when people cut down on fats they tend to eat more bread, cold cereal and other refined carbohydrates that can also be bad for cardiovascular health.
The single macronutrient approach is outdated, said Dr. Hu, who was not involved in the study. I think future dietary guidelines will put more and more emphasis on real food rather than giving an absolute upper limit or cutoff point for certain macronutrients.
He said people should try to eat foods that are typical of the Mediterranean diet, like nuts, fish, avocado, high-fiber grains and olive oil. He referred to a large clinical trial which was published last year in the New England Journal of Medicine, and was not included in the current analysis, which found that a Mediterranean diet with more nuts and extra virgin olive oil reduced heart attacks and strokes when compared with a lower fat diet with more starches.
ACSH s Dr. Gilbert Ross had this comment: I for one am glad to see this, at last. Based upon my experiences in clinical practice over the course of twenty years, I found it extremely difficult to persuade patients to radically cut down on saturated fat to lower their LDL levels and, theoretically, their heart risk. Now we see that this endeavor may not be worth the time and effort, for both doctor and patient.