Triglyceride-lowering effect of n-3 long chain polyunsaturated fatty acid: eicosapentaenoic acid vs. docosahexaenoic acid.

Abstract

It is widely accepted that fish oil decreases serum triglycerides. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are believed to be the active components. By far the majority of animal experiments and human trials investigating the effect of n-3 long chain polyunsaturated fatty acid on serum triglyceride levels were carried out with fish oil concentrates containing both EPA and DHA. Little information exists on the effect of EPA or DHA on serum triglyceride levels as a single agent. This paper reviews the results of human studies which investigated the effect of EPA and DHA on serum triglycerides. The results of human intervention studies investigating the effects of purified EPA and DHA on plasma triglycerides clearly demonstrate that EPA as well as DHA, given as a single agent, significantly and consistently lowers plasma triglyceride levels. In the papers reviewed, the triglyceride-lowering effect of 2.7-4.0 g EPA per day varied between 16 and 33%. A daily dose of t.25-2.5 g of DHA resulted in a trigtyceride reduction of 17-21%. Only a few studies have been published SO far which were designed to investigate the effect of purified EPA vs. purified DHA on fasting triglycerides. Two recently published clinical trials investigated the triglyceride-lowering effect of 4.0 g EPA vs. 4.0 g DHA in healthy young men. These studies revealed a serum triglyceride decrease of 12 and 18% in the EPA group and of 17 and 20% in the DHA group, respectively. A study which investigated the effect of a supplementation with EPA vs. DHA on the postprandial triglyceride surge reported a marked decrease of the postprandial triglyceridemia in both the EPA and the DHA group, though this effect was more pronounced in the people who received DHA. The effect of EPA and DHA on serum lipids such as total cholesterol, low density lipoprotein-cholesterol, and high density lipoprotein, however, appears to be less consistent. In summary, the available evidence points to the fact that both EPA and DHA have a marked hypotriglyceridemic effect in humans. As it regards the effect of purified EPA and DHA on lipoprotein subfractions, there may be some differences that warrant further clarification.