The study – published in Cell Metabolism – investigated the effects of resveratrol supplementation on the metabolic functions of healthy women, finding that the popular supplement may not have a benefit in terms of metabolic changes.
Led by Dr Samuel Klein, from Washington University's Centre for Human Nutrition, USA, the research team noted that previous research into the grape compound has suggest its ability to improve insulin sensitivity, reduce risk of heart disease and increase longevity.
However, data from the small scale current study suggests resveratrol does not appear to offer these benefits in healthy women.
"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," said Klein. "But our data demonstrate that resveratrol supplementation does not have metabolic benefits in relatively healthy, middle-aged women."
The authors said that this finding was somewhat surprising, because earlier research has suggested consumption of the compound in red wine or via supplements may lower the risk of health problems.
"Few studies have [however] evaluated the effects of resveratrol in people," Klein explained. "Those studies were conducted in people with diabetes, older adults with impaired glucose tolerance or obese people who had more metabolic problems than the women we studied.
“So it is possible that resveratrol could have beneficial effects in people who are more metabolically abnormal than the subjects who participated in the study."
Klein and his team analysed data from involved 29 post-menopausal women who did not have type 2 diabetes and who were reasonably healthy.
For 12 weeks, half took an over-the-counter resveratrol supplement containing 75 milligrams of resveratrol (resVida 99.7% transresveratrol, by DSM Nutritional Products) daily, while the rest received a placebo. This supplementation is equal to the amount of resveratrol gained from drinking eight litres of red wine, they said.
The researchers then compared insulin sensitivity to the 14 participants who received the placebo.
“We were unable to detect any effect of resveratrol,” said Klein.
“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 signalling pathways involved in metabolism," he said.
Red wine benefits?
Klein also questions why, if resveratrol does not have a health benefit, are red wine drinkers less likely to develop heart disease and diabetes?
In his opinion, this may be due to other compounds in red wine, that may even act in synergy.
"The purpose of our study was not to identify the active ingredient in red wine that improves health but to determine whether supplementation with resveratrol has independent, metabolic effects in relatively healthy people," he said.
"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."
Source: Cell Metabolism
Published online ahead of print, doi: 10.1016/j.cmet.2012.09.015
“Resveratrol Supplementation Does Not Improve Metabolic Function in Nonobese Women with Normal Glucose Tolerance”
Authors: Jun Yoshino, Caterina Conte, Luigi Fontana, Bettina Mittendorfer, Shin-ichiro Imai, Kenneth B. Schechtman, et al