Background: This study was conducted to determine the effects of n-3 PUFAs supplementation on plasma homocysteine (Hcy) level, lipid profile and insulin resistance in patients with type 2 diabetes (T2D). Methods: This study is a double-blind controlled trial involving 70 patients with T2D selected from Yazd Diabetes Research Center in 2013. Patients were randomly assigned to receive either 2 g/day omega-3 soft gels (OG) or 2 g/day placebo (PG) for 6 weeks. At the beginning and end of the study, Hcy concentration, fasting plasma glucose (FBG), fasting plasma insulin, total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), HDL-c/LDL-c ratio, insulin resistance (HOMA-IR), insulin sensitivity (IS) and beta-cell function were measured and compared. Results: Sixty five participants completed the study. The results of this study showed that
omega-3 fatty acid supplementation caused significant increase in Hcy
(P = 0.007) and LDLc (P = 0.02), while HDLc and HDLc/LDLc ratio were significantly decreased (P = 0.001 and 0.006, respectively). In both groups, insulin and HOMA-IR were increased, while IS decreased significantly. Βeta-cell function was increased only in OG (P = 0.005). There was no significant difference in mean change of any factors. Conclusion: The present study found no beneficial effects of 2 g/day omega-3 supplement for 6 weeks on biomarkers of Hcy, FBG, insulin and lipid profile in th T2D patients.