Many observational studies have shown that moderate alcohol drinkers have lower incidences of type 2 diabetes mellitus and cardiovascular disease than do nondrinkers or heavy drinkers. Mixed results have been reported on whether red wine has special benefits over other alcoholic beverages.
An international group conducted a study that involved 224 Israeli adults (age range, 40–75) with type 2 diabetes who regularly drank no more than one alcoholic drink weekly at baseline. The participants all ate a Mediterranean diet, without caloric restriction, and were randomized to drink 150 mL of red wine, white wine, or mineral water each evening (drinks were provided for free). Adherence was excellent. At 2 years, compared with water drinkers, the red wine drinkers had higher HDL cholesterol levels (by 2 mg/dL), lower total/HDL cholesterol ratios, and fewer markers for metabolic syndrome; the white wine drinkers had lower fasting blood glucose and triglyceride levels and less insulin resistance. No between-group differences were found in blood pressure, adiposity, liver function, drug therapy, symptoms, or quality of life (except that wine drinkers reported sleeping better).