Effects of EPA and Vitamin E on Serum Enzymatic Antioxidants and Peroxidation Indices in Patients with Type II Diabetes Mellitus

BACKGROUND Diabetes mellitus is associated with chronic changes in peripheral arteries because of oxidative stress and insufficient antioxidative defense mechanism. Omega-3 fatty acid supplementation could be effective in some diabetes complications; however, polyunsaturated fatty acids may increase lipid peroxidation. This study aimed to determine whether eicosapentaenoic acid alone or in conjunction with vitamin E had differential effects on serum antioxidants and peroxidation indices. METHODS This double-blind, placebo-controlled trial was carried out on 136 patients with type II diabetic mellitus (age 48.8±4.4 yr, BMI 27.8±1.7 kg/m(2)). The four groups of the study either received two grams of omega-3 fatty acids, 400 IU of vitamin E, a combination of the two or placebo for three months. Their serum total antioxidant capacity, enzymatic antioxidants and peroxidation indices were assessed. RESULT Fasting serum TAC increased in EPA+E (10.7%, P< 0.001) and E groups (7.5%, P< 0.05). SOD, G-PX and G-RD increased in EPA group (7.3%, 5.1%, and 8.4%, P< 0.05, respectively). MDA and protein carbonyl decreased in EPA and E groups (respectively, 12.5%, 7.6% P< 0.05, P< 0.05; 13%, 15.3% P< 0.001, P< 0.05). After adjustment for baseline values, age, sex, BMI and duration of diagnosed diabetes, protein carbonyl decreased in EPA+E and E group (30.7%, 15.3%; P< 0.05 respectively) relative to the placebo group. CONCLUSION EPA, by itself has a statistically significant effect on serum total antioxidant capacity, enzymatic antioxidants and peroxidation indices in diabetic patients compared to EPA+E or E alone. TRIAL REGISTRATION ClinicalTrials.gov NCT00817622.