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/m²). 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