Studies on the Effects of Diets Realistic for Westernized People on Plasma Lipoprotein Composition, Metabolism, and Atherosclerosis in Vervet Monkeys

Abstract

Using diets realistic for Westernized people, which consist entirely of normal foods for humans, has added to our knowledge regarding the impact of diet on plasma lipoprotein metabolism and atherosclerosis in Vervet monkeys. The overall effect of a Western atherogenic diet (WAD) on the progression and a prudent diet (PD) on the regression of atherosclerosis were confirmed. Although atherosclerosis is closely associated with increased levels of low-density lipoprotein cholesterol (LDL)-C, the increased levels of LDL-C measured in these studies were brought about by an increased number of circulating LDL particles of relatively unchanged composition without enrichment of the LDL core with cholesterol esters.This model proved to be valuable for studying the effects of a variety of dietary supplements such as fish oil, EPA, palm olein and blood lipid lowering agents such as etofibrate, on plasma lipoprotein metabolism, LDL composition, LDL turnover and atherosclerosis. Results from the studies with eicosapentaenoic acid (EPA) and gammalinolenic acid (GLA) supplementation showed a slower rate of metabolism of these fatty acids in animals consuming the WAD. These findings signal a warning against the indiscriminate use of supplements by individuals at risk of hyperlipoproteinemia. Results from the studies following the disappearance of EPA and GLA from tissues after supplementation provide a potential model for determining the daily requirement of n-3 fatty acids in an individual under different dietary conditions.