Red Wine Polyphenols Help to Improve Glucose Metabolism

Red wine is abundant in polyphenols, a potent type of antioxidant.  Gemma Chiva-Blanch, from the University of Barcelona (Spain), and colleagues enrolled 67 men with a high cardiovascular risk, and randomly assigned each to consume a red wine (30 g of alcohol per day), dealcoholized red wine, and gin (30 g of alcohol per day), for four weeks. The researchers found that both forms of wine decreased insulin resistance between 22 and 30%, compared to values at the start of the study; and between 14 and 22% compared to the gin group. As well, both the red wine and gin improved HDL ("good") cholesterol levels, compared to the dealcoholized red wine group, suggesting that these benefits are related to the alcohol, rather than the polyphenol content. Lipoprotein(a) decreased after the red wine intervention. The study authors conclude that: "These results support a beneficial effect of the non-alcoholic fraction of red wine (mainly polyphenols) on insulin resistance, conferring greater protective effects on cardiovascular disease to red wine.”