(n-3) Fatty Acids: Clinical Trials in People with Type 2 Diabetes.

Recent human clinical trials of the effects of (n-3) fatty acids on participants with type 2 diabetes (T2D) were reviewed, focusing on 11 clinical trials conducted within the past 4 y, and subsequent to a Cochrane Database meta-analysis of this topic. Doses of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in these studies were mostly in the range of ∼2 g/d provided for 6 wk to 6 mo. Summarizing across these studies, there were no changes in fasting glucose or insulin compared with baseline or placebo. (n-3) Fatty acids generally decreased serum triglycerides but had varying effects on serum cholesterol, LDL cholesterol, and HDL cholesterol. A few studies indicated beneficial effects of (n-3) fatty acids on arterial blood flow. The effects of EPA and/or DHA have not yet been studied in clinical trials in participants at risk for T2D; the prevention or exacerbation of T2D by fish oil or EPA and DHA supplements of amounts >0.5 g/d deserves study. The prevention of adverse vascular effects of T2D by (n-3) fatty acids may be a promising direction for further study.