The small but intensive study involving 11 obese but healthy men found that taking a relatively low dose of resveratrol daily for a month produced a variety of fundamental beneficial effects on their metabolism.
“We are very excited,” said Patrick Schrauwen of Maastricht University in The Netherlands, whose research was posted online by the journal Cell Metabolism. “We found a lot of effects that all point in the same direction of better metabolic health.”
Many scientists have been excited about resveratrol since studies in yeast, fruit flies and laboratory mice indicated the substance could mimic the benefits of consuming a very low-calorie diet, which has been shown to extend longevity in many species. Some people severely restrict their caloric intake in the hopes of living longer. But most people find it difficult if not impossible to adopt such a stringent lifestyle.
Resveratrol also appeared to protect mice from obesity and diabetes, boost the animals’ physical endurance, reduce their chances of suffering the ill effects of obesity and extend their lives.
Such findings prompted some scientists to speculate that the presence of trace amounts of resveratrol in red wine might help explain the “French paradox,” which is that the French consume a relatively rich diet, but live as long as anyone else.
Some people have even started taking resveratrol, which is sold over-the-counter in health and grocery stores. But the benefits for people have never been shown and the potential risk of high doses for long periods remains unknown and some scientists have questioned the validity of some of the early research.
In the new study, Schrauwen gave 150 milligrams or a placebo to the healthy obese men for 30 days and then switched those on placebo to resveratrol and vice versa for another month. Each time they conducted a series of detailed tests to examine the impact on their metabolism.
Resveratrol appeared to produce all the same effects in the human subjects as it had in animals, such as lowering the metabolic rate, cutting the accumulation of fat in the liver, reducing blood sugar, blood pressure, triglycerides and inflammation and boosting the efficiency of muscles. There were no apparent side effects.
“I think it’s very promising,” said Rafael de Cabo of the National Institute on Aging, who has been studying resveratrol in monkeys.”It’s very significant.”
The researchers noted that the dose was much lower than that used in animal studies and the amount many people take on their own. But someone would have to drink at least about two gallons of red wine a day to get the equivalent amount of resveratrol.
The findings were praised by other researchers who have been studying resveratrol and other compounds that increase proteins known as sirtuins thought to have the beneficial effects.
“This study comes at a time when obesity and diabetes are reaching epidemic proportions,” said David A. Sinclair of Harvard Medical School. “Sirtuins offer the promise that we can find ways to prevent the effects of obesity and sedentary lifestyles.”
“This paper is important,” said Leonard P. Guarante, who studies aging at the Massachusetts Institute of Technology. “It suggests that sirtuin-based drugs is a promising new strategy to treat human diseases.”
Schrauwen and others cautioned, however, that much more research is needed to follow up on the study to determine if resveratrol’s effects translate into health benefits, especially for those who are not obese, and whether it is safe over the long term.
“Although it is a bit early, we may soon find ourselves looking back on the discovery and development of resveratrol ... and other related small molecules that can delay age-related disorders and improve healthy life span as a truly historic point in aging research,” said Stephen Helfand of Brown University.
“The finding of molecules with such dramatic positive effects on age-related disorders and life span is a major conceptual leap forward for the field of aging research, perhaps equivalent to the effect of the discovery of antibiotics on treating infectious diseases,” Helfand said. “It is an extraordinary time to be involved in research on the biology of aging.”