Although a red wine ingredient, known as resveratrol, has been known to reduce the risk of heart disease, improve insulin sensitivity, and increase longevity, these benefits are not seen in healthy women.

The finding, published in Cell Metabolism, came from a team of researchers at Washington University School of Medicine in St. Louis after observing 29 women who did not have type 2 diabetes, had already gone through menopause, and who were fairly healthy overall.

The subjects were randomly divided into two groups – one group took an over-the-counter resveratrol supplement and the other took a placebo (sugar pill).

Samuel Klein, M.D., director of Washington University’s Center for Human Nutrition and the study’s senior author, explained:

“Resveratrol supplements have become popular because studies in cell systems and rodents show that resveratrol can improve metabolic function and prevent or reverse certain health problems like diabetes, heart disease and even cancer. But our data demonstrate that resveratrol supplementation does not have metabolic benefits in relatively healthy, middle-aged women.”

Since previous studies have suggested that drinking red wine can lower the risk of serious health issues, the results were quite surprising. For example, one study indicated that certain compounds found in red wine contribute toward the long life span of red wine drinkers. A different report found that red wine can reduce the risk of breast cancer.

However, there have been few reports analyzing the impact resveratrol has on people, said Klein. The participants in those studies consisted of older adults with impaired glucose tolerance, people with diabetes, or obese patients with more metabolic issues than the females observed in the current study.

In other words, Klein explained, the reason could be that resveratol offers advantages to individuals who are more metabolically abnormal than the participants in this research.

The majority of people want to take resveratrol supplements because they have heard about the benefits associated with red wine, but do not want to drink too much alcohol, according to Klein. Annual sales of these supplements have increased to $30 million in the United States in recent years.

The team gave 15 post-menopausal women 75 milligrams of resveratrol daily, which equalled out to the same amount they would receive from consuming 8 liters of red wine.

The group’s insulin sensitivity was then compared to the 14 others in the placebo group, along with the rate of glucose uptake in their muscles, by infusing insulin into their bodies and analyzing their metabolic response to various doses.

Klein said:

“It’s the most sensitive approach we have for evaluating insulin action in people. And we were unable to detect any effect of resveratrol. In addition, we took small samples of muscle and fat tissue from these women to look for possible effects of resveratrol in the body’s cells, and again, we could not find any changes in the signaling pathways involved in metabolism.”

If resveratrol is not beneficial, there may be another ingredient in red wine that is, since red wine drinkers have a lower chance of developing heart disease and diabetes.

The research was not designed to recognize the active ingredient in red wine that improves health, but to decide whether supplementation with resveratrol independly effects the metabolic system in fairly healthy people.

Klein concluded: “We were unable to detect a metabolic benefit of resveratrol supplementation in our study population, but this does not preclude the possibility that resveratrol could have a synergistic effect when combined with other compounds in red wine.”.

Written by Sarah Glynn