International Journal of Preventive Medicine (Int J Prev Med)2008-78021120120414922928ENDepartment of Nutrition and Biochemistry, School of Public of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Nutrition and Biochemistry, School of Public of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Nutrition and Biochemistry, School of Public of Health, Tehran University of Medical Sciences, Tehran, IranIranian Diabetes Society, Tehran, IranInstitute of Endocrinolgy and Metabolism, Firouzgar Hospital, Tehran University of Medical Sciences, Tehran, IranDepartment of Nutrition and Biochemistry, School of Public of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Biostatistics, School of Management and Medical Information, Tehran University of Medical Sciences, Tehran, Iran20120414<p><strong>Objectives: </strong>N‑3 Fatty acids reduce the risk of cardiovascular disease. Previous studies have shown that they may reduce inflammation, oxidative stress, and fat mass in patients with type 2 diabetes, but the results are inconclusive, due, in part, to type of omega‑3 fatty acids used. The aim of this study was to determine the effects of pure eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), the two major omega‑3 fatty acids, on inflammation, oxidative stress, and fat mass in patients with type 2 diabetes.</p> <p><strong>Methods: </strong>Sixty patients with DM‑II were randomly allocated to receive daily either ~1 gr EPA or ~1 gr DHA, or a canola oil as placebo for 12 weeks in a randomized triple‑blind, placebo‑controlled trial. Serum MDA, CRP, body weight, BMI, and fat mass were measured at baseline and after intervention.</p> <p><strong>Results: </strong>Forty‑five patients with a mean (&plusmn;SD) age of 54.9 &plusmn; 8.2 years with BMI of 27.6 &plusmn; 4.1 kg/m2 and fasting blood glucose 96.0 &plusmn; 16.2 mg/dl completed the intervention. Neither EPA nor DHA had significant effects on serum FBS, C‑reactive protein, body weight, BMI, and fat mass after intervention (<em>P </em>&gt; 0.05). In addition, while MDA increased 18% in the placebo group (<em>P </em>= 0.009), it did not change in the EPA or DHA group (<em>P </em>&gt; 0.05).</p> <p><strong>Conclusions: </strong>Twelve weeks of supplementation with 1gr/d EPA or DHA prevent increasing oxidative stress without changing marker of inflammation. This study is the first report demonstrating that neither EPA nor DHA have effects on body fat mass in type 2 diabetic patients.</p> <strong>Key words: </strong>Inflammation, omega 3 fatty acids, oxidative stress, type 2 diabetes mellitushttp://ijpm.mui.ac.ir/index.php/ijpm/article/view/671http://ijpm.mui.ac.ir/index.php/ijpm/article/download/671/1102