Potential Effects of Omega-3 Fatty Acid Supplements in the Prevention of Type 2 Diabetes: A Critical Appraisal of Data from Randomized Clinical Trials

Abstract

Emerging evidence has suggested favorable effects of marine omega-3 fatty acids on glucose homeostasis, lipid metabolism, endothelial function, and chronic inflammation, which could contribute individually or synergistically to the development of type 2 diabetes (T2D). With increasing prevalence of use of fish oil supplements and increasing fortification of the food supply with marine omega-3 fatty acids in the general population, it will be critically important to assess the overall balance of benefits and risks of omega-3 fatty acid supplements on glucose tolerance and diabetes. This article aims to summarize the evidence from available randomized clinical trials on the potential effects of fish oil and/or omega-3 fatty acid supplements among both nondiabetic and diabetic participants. Overall, the evidence for the beneficial or deleterious effects of fish oil supplements on insulin sensitivity has been inconsistent, with limited randomized trial data involving small trials of short duration. However, dietary recommendation of taking omega-3 fatty acids for prevention of T2D or diabetic complications may ultimately only be resolvable by definitive data from future large-scale clinical trials that include T2D as a primary outcome in a general population.