Grape seed extract modifies insulin resistance induced by a high fat/carbohydrate meal in metabolic syndrome patients

Insulin resistance is a characteristic feature of metabolic syndrome (MS) and is known to be associated with a relatively high postprandial plasma glucose concentration. We have shown previously that consumption of a meal that is high in readily available carbohydrates/fat causes a postprandial increase in markers of oxidative stress and insulin resistance. The present investigation was undertaken to determine whether a grape seed extract (GSE‐Meganatural © Gold) that is rich in antioxidants would modify these post‐prandial responses in individuals with the MS. After an overnight fast, twelve subjects with MS (6 men and 6 women) consumed a high‐carbohydrate, moderate‐fat meal in a cross‐over design. A GSE (300 mg) or placebo capsule was administrated 1 h before the meal. Postprandial changes in plasma insulin, glucose, oxidative stress and inflammatory markers were measured hourly for 6 h. Postprandial plasma glucose concentrations (area under the curve over 6 hr) were significantly lower when the meal was preceded by GSE compared with placebo (P=0.04). Postprandial insulin concentrations remained unchanged (P>0.05). Meal‐induced increases in oxidized LDL were attenuated with GSE capsule (P<0.05), whereas IL‐6 and TNF‐α concentrations were unchanged after the two treatments (P>0.05). These data suggested that GSE enhances postprandial insulin sensitivity in subjects with the MS. Study was supported by Polyphenolic Inc. Madera, CA