Effects of eicosapentaenoic acid and vitamin C on glycemic indices, blood pressure, and serum lipids in type 2 diabetic Iranian males

BACKGROUND: Eicosapentaenoic acid (EPA) is the principal ω-3 fatty acids in marine oils. Fasting blood sugar (FBS), HbA1c and some of the plasma lipids and lipoproteins has been negatively related to the intake of ω-3 fatty acids and ascorbic acid, in some studies. Therefore, the purpose of this study was to assess the effects of EPA and/or vitamin C on glycemic indices, blood pressure, and plasma lipids in type 2 diabetic Iranian males. METHODS: Sixty five men with type 2 diabetes were enrolled into the study between April 2 and June 27, 2008. Venous blood samples were obtained from all participants after 10 hours of fasting, at the baseline and after the intervention. Subjects received 500 mg EPA and/or 200 mg vitamin C and/or placebo depending on their groups. For eight weeks, 15 participants received EPA supplements with vitamin C (group 1), 16 took EPA supplements and vitamin C placebo (group 2), 17 took EPA placebo and vitamin C (group 3), and 17 received EPA placebo and vitamin C placebo (group 4), daily. RESULTS: There were significant decreases in FBS, HbA1C, LDL-C and TG in groups 1, 2, 3 and 4 (p < 0.01), but significant decreases in TC were shown only in groups 1, 2 and 3 (p < 0.01). There was a significant increase in HDL-C in all groups (p < 0.01). CONCLUSIONS: In summary, it is concluded that, eight weeks of taking EPA + vitamin C supplementation improved the plasma levels of cardiovascular markers but didn't reduce BP.