In a small study, high-dose resveratrol supplementation had no effect on insulin sensitivity and certain other metabolic parameters in obese men, despite promising findings from some animal studies, researchers reported online in Diabetes.
Morten Poulsen, MD, of Aarhus University Hospital in Denmark, and colleagues randomized 24 obese but otherwise healthy men to receive four weeks of resveratrol—a potent antioxidant found in the skins of grapes and in red wine—or placebo. Insulin sensitivity, which was the primary outcome measure in the study, deteriorated insignificantly in both groups, the researchers found. In addition, endogenous glucose production and the turnover and oxidation rates of glucose remained unchanged. Resveratrol also had no effect on inflammatory and metabolic biomarkers, blood pressure, lipid oxidation rates, resting energy expenditure, and ectopic or visceral fat content.
Dr. Poulsen’s group concluded that their findings “raise doubt about the justification of resveratrol as a human nutritional supplement in metabolic disorders.”