Prevention of insulin resistance by n-3 polyunsaturated fatty acids.
OBJECTIVE
Review results from recent human and animal studies regarding the effects of n-3 polyunsaturated fatty acid (PUFA) in the prevention of insulin resistance.


RESULTS
Overall, results from animal studies indicate that fish oil and individual n-3 PUFA [alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)] prevented insulin resistance in animal models; results from two studies in mice showed that EPA increased insulin secretion. ALA, EPA, and DHA may act at different sites and involve different mechanisms. Fish oil or purified EPA reduced insulin resistance in some but not other human studies in normal weight and obese individuals. Discrepancies may be due to differences in health status of participants, macronutrient, fatty acid, and antioxidant nutrient composition of basal diet; amount, duration, and fatty acid composition of n-3 PUFA, and methods used to assess insulin resistance. Moderate amounts of n-3 PUFA did not improve or deteriorate glucose control in type 2 diabetics.


CONCLUSIONS
n-3 PUFA supplementation has clinical significance in the prevention and reversal of insulin resistance. However, increased intake of n-3 PUFA should be part of an overall healthy lifestyle that includes weight control, exercise, and reduction in the intake of refined sugars, n-6, saturated, and trans fatty acids.
Fedor
Dawn
D
Western Human Nutrition Research Center, ARS, USDA Department of Nutrition, University of California, Davis, California 95616, USA.
Kelley
Darshan S
DS
D000818:Animals; D003920:Diabetes Mellitus / Q000188:drug therapy; D004195:Disease Models, Animal; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology / Q000627:therapeutic use*; D005395:Fish Oils / Q000627:therapeutic use; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000188:drug therapy; D007333:Insulin Resistance; D051379:Mice; D009765:Obesity / Q000188:drug therapy; D051381:Rats
D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D005947:Glucose