Despite showing early promise in some animal studies, supplements of resveratrol, an antioxidant found aplenty in red wine, did not improve insulin sensitivity or heart health in obese men, a small trial found.
Researchers found no difference in insulin sensitivity — the measure of how well the body uses the hormone insulin — in 24 obese but otherwise healthy men who took daily 1,500-milligram doses of resveratrol compared to other men who took an inactive placebo for four weeks.
Nor were there any changes in other signs of heart health, including blood pressure, levels of blood fats called triglycerides and other fats.
The study, led by Dr. Morten Poulsen at Aarhus University Hospital in Denmark, appears online Nov. 28 in the journal Diabetes.
Dr. Vivian Fonseca, president of medicine and science for the American Diabetes Association, said he is not surprised that the study did not show any benefits associated with the resveratrol supplements.
“People who drink red wine and do so in moderation may have healthy lifestyles that may allow them to live longer and decrease their insulin sensitivity, but putting it into a pill doesn’t solve the problem for people who live unhealthy lives, like the men in the study,” Fonseca said. “I think some of the initial animal studies on resveratrol were hyped far more than they should have been and this study should put all of that to rest.”
Dr. John Buse, a professor of medicine at the University of North Carolina at Chapel Hill, agreed. “It is nice to see the lack of efficacy so elegantly demonstrated,” he said. “There cannot be much question remaining at this point.”
People at risk for diabetes can take preventive measures, he noted. “The most important thing is to be screened for diabetes if you are at risk,” Buse said. This includes everyone older than 45 and younger people who are overweight.
“To reduce the risk of diabetes, reduce calorie intake with an aim to reduce weight by 5 to 10 percent and increase physical activity to at least 30 minutes at least five days a week,” Buse advised. “That reduces diabetes risk by about 60 percent over three years.”
For her part, Dr. Tara Narula, associate director of cardiac care at Lenox Hill Hospital in New York City, said, “People are always looking for a one-stop, easy cure-all supplement or quick fix, but the things that work require work.”
While these supplements may not stack up, moderate alcohol consumption may have some health benefit, Narula said. “If you are going to drink, red wine is the one that I recommend because there is a potential benefit from compounds in the wine itself,” she added.
That’s good advice, said Dr. Howard Weintraub, a cardiologist at NYU Langone Medical Center. “There are benefits within the wine that extend beyond the resveratrol, and part of it may be because alcohol helps improve good cholesterol,” he said. “If you enjoy red wine, a glass or two a day may be beneficial.” But, he cautioned, just because a glass or two can be good for you doesn’t mean that more is better.