Brown TJ, et al. - In a systematic review and meta-analyses of 83 randomized controlled trials, researchers evaluated the impact of increasing omega-3, omega-6, and total polyunsaturated fatty acids (PUFA) on diabetes diagnosis and glucose metabolism. Long-chain omega-3 had little or no impact on the probability of a diagnosis of diabetes or measures of glucose metabolism. When the dose of supplemental long-chain omega-3 was above 4.4 g/d, a suggestion of negative outcomes was noted. Impact of α-linolenic acid, omega-6, and total PUFA on the diagnosis of diabetes were unclear; however, little or no effect on measures of glucose metabolism was observed, except that increasing α-linolenic acid may enhance fasting insulin. There was no evidence that the omega-3/omega-6 ratio was significant for diabetes or glucose metabolism. This is the most extensive systematic review of trials on this subject matter to date, including formerly unpublished data. Overall, boosting omega-3, omega-6, or total PUFA had limited or no impact on the prevention and treatment of type 2 diabetes.