Dietary antioxidants and glucose metabolism

Purpose of review Oxidative stress seems to play a pathogenic role in the vicious circle linking obesity, insulin resistance and type 2 diabetes. Hypothetically, dietary antioxidants should decrease oxidative stress and therefore improve glucose metabolism. However, many interventional trials evaluating the effect of antioxidant supplementation on insulin resistance, plasma glucose levels and risk of type 2 diabetes gave inconsistent results. Recent findings Many studies have recently demonstrated a positive effect of vitamin supplementation and of food enriched in antioxidant (seafood, whole nut, etc.) on markers of oxidative stress, insulin resistance, fasting plasma glucose and incidence of diabetes. The present paper critically reviews the consolidated notions on dietary antioxidant in view of the recent evidences. Summary Although a definitive estimation of the impact of dietary antioxidants on glucose metabolism is still lacking, food with high antioxidant concentrations seems to have a protective effect, improving oxidative stress-mediated detrimental effects on the vicious circle among obesity, insulin resistance and redox imbalance.