n-3 fatty acids and serum lipoproteins: human studies.
The effects of n-3 fatty acids from fish oils (eicosapentaenoic acid and docosahexaenoic acid) and plant oils (alpha-linolenic acid) on human serum lipids and lipoproteins are reviewed. Studies were included in this review if they were placebo-controlled, crossover, or parallel design studies providing < 7 g n-3 fatty acids/d and with treatment periods of > or = 2 wk duration. Only three studies were available for evaluation of the effects of alpha-linolenic acid on serum lipid concentrations. From these studies it appeared that alpha-linolenic acid (18:3n-3) was equivalent to n-6-rich oils vis-vis lipid and lipoprotein effects. Only when very large amounts of flaxseed oil were fed did the hallmark effect of marine n-3 fatty acids-reduced triacylglycerol concentrations-appear. Thus, in terms of effects on lipoprotein metabolism, the plant-derived n-3 fatty acid is not equivalent to the marine-based acids. More studies using the marine-based acids were examined and summarized. Both crossover (n = 36) and parallel (n = 29) design studies reached the same conclusions: total cholesterol is not materially affected by n-3 fatty acid consumption, low-density-lipoprotein cholesterol concentrations tend to rise by 5-10% and high-density-lipoprotein cholesterol by 1-3%, and serum triacylglycerol concentrations decrease by 25-30%. These effects of marine n-3 fatty acids are now well-established; what remains is to determine the mechanisms behind these effects and, more importantly, their health consequences.
Harris
W S
WS
Metabolism and Vascular Research Laboratory, Mid America Heart Institute, St Luke's Hospital, Kansas City, MO 64111, USA. wharris@saint-lukes.org
D002784:Cholesterol / Q000097:blood; D002986:Clinical Trials as Topic; D018849:Controlled Clinical Trials as Topic; D018592:Cross-Over Studies; D004032:Diet / Q000592:standards; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D006801:Humans; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood*; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D014280:Triglycerides / Q000097:blood; D017962:alpha-Linolenic Acid / Q000494:pharmacology
D015525:Fatty Acids, Omega-3; D008055:Lipids; D008074:Lipoproteins; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D002784:Cholesterol; D015118:Eicosapentaenoic Acid