A study to be published in the August 15 edition of the Journal of the American College of Cardiology shows that eating a single meal high in saturated fats effectively blocks the beneficial effects of HDL cholesterol (i.e., "good" cholesterol), and reduces the normal functioning of arteries.
Researchers from the Cleveland Clinic studied 14 healthy volunteers, having them eat two separate meals, one month apart. One meal was high in saturated fat (delivered, in this experiment, via coconut oil), and the other was high in polyunsaturated fat (safflower oil). Within three hours of eating the meal high in saturated fat, measurements showed that the ability of the arteries to dilate normally was significantly reduced. In addition, the investigators found that within six hours of eating the meal high in saturated fat, the protective effects of HDL cholesterol were reduced. Specifically, after the high-saturated-fat meal, substances that cause inflammation were increased in the walls of the arteries - an effect that is normally blocked by HDL cholesterol. After the meal consisting of polyunsaturated fat, however, the anti-inflammatory properties of HDL cholesterol were boosted.
DrRich Comments:
This study reveals a new effect of saturated fats. Not only do these fats increase cholesterol levels, but they also block the protective effects of HDL cholesterol. If borne out in further studies, this new finding will throw a monkey wrench in the notion that the "classic" Atkins diet- wherein dipping your pork rinds in lard would make a perfectly acceptable snack - is either safe or smart. Avoiding "fast" carbohydrates appears to be a good idea (a basic tenet of both the Atkins and the South Beach diet), but substituting with saturated fats (advice promoted only by the Atkins diet) does not.
Sources:
Nicholls SJ, Harmer JA, Cutri B, et al. Consumption of Saturated Fat Impairs the Anti-inflammatory Properties of High-Density Lipoproteins and Endothelial Function. JACC, 48:715; 2006.
