A new study shows that when taken regularly a natural compound known as resveratrol, found in red wine and grapes, mulberries and peanuts, can offer similar benefits to low-calorie diets and endurance training.
The compound not only lowers the metabolism – meaning the body needs less food to generate enough energy – it can reduce levels of liver fat, blood pressure and blood sugar. It improves rate at which the muscles burn fat, lessens insulin resistance and could protect against certain age-related diseases like type 2 diabetes and cancer, experts said.
The dose needed is equivalent of 13 bottles of wine per night. But researchers said the 150mg dose could easily be taken as a daily capsule with water, or incorporated into existing food supplements.
Prof Patrick Schrauwen of Maastricht University in The Netherlands, who led the study, said the benefits of resveratrol for obese people were small but significant. He said, “I think the positive thing is that they were very consistent, they cause a small difference on a lot of different parameters. Also, we only gave it to patients for 30 days and we do not know what would happen if we gave it for longer. Metabolic changes can take a while before they start to appear so it is quite possible the effects could be larger.”
Dr Andrew Murray, of Cambridge University, who was not involved in the study, said it provided the first real evidence that resveratrol could have a significant effect in humans. He said, “Although the effects are slight they could make all the difference to people with metabolic complications like obesity. What is very exciting about this is that there are many problems related to obesity and the onset of diabetes, and what this study seems to show is that it is not going to make people thin again but it could slow down all the problems associated with lifelong obesity.”
The researchers gave daily resveratrol to 11 obese male patients for a month and found it altered their metabolism in a similar, although weaker, way than extreme dieting or endurance training. The treatment lowered systolic blood pressure by 5mmHg and reduced the amount of energy participants used by two to four per cent, indicating that their metabolism had slowed down.
Calorie restriction works in a similar way to resveratrol, by triggering the production of a protein called SIRT1 which improves metabolic function and keeps cells healthy in the face of stress. Muscle biopsies carried out by Prof Schrauwen's team confirmed that participants taking resveratrol saw increased SIRT1 levels. They also strongly suggested the beneficial effects on metabolism were associated with improved functioning of mitochondria, the energy factories within cells.
Prof Schrauwen said, “In our society with so much obesity people want to have a high metabolism because it is easier to lose weight. But the lowering of your energy metabolism is actually a good thing because it means that you become more efficient.” Because the eleven patients tested in the study, published in the Cell Metabolism journal, were all obese men it is not clear whether slimmer people would benefit in the same way. Prof Schrauwen said, “I can imagine it will work better in people who already have some disturbances in their metabolism – if your blood pressure and blood glucose are normal, then it might not be lowered.”
“It would be a mistake to even hint that resveratrol could be a license to forego attempts at eating well and being active,” said Dr. David Katz, director of the Yale University Prevention Research Center. “Eating well and being active can help prevent heart disease, cancer, stroke and diabetes. We have no evidence yet - and might never have any - that resveratrol can do these things. Even if resveratrol lives up to its early promise, it should be combined with best efforts at living well, not substituted for them.”
“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.” “That's good news,” said Keith Ayoob, director of the Rose R. Kennedy Center Nutrition Clinic at Albert Einstein College of Medicine in New York City, “but I'd be concerned that it might make people be more tolerant of their obesity, since they'd be able to mitigate some of the metabolic complications of being overweight.”
Schrauwen said no side effects were seen throughout the study, but cautioned that more research is needed to understand the supplement's long-term effects. The study also opens the door for the development of new, more potent drugs that target the same pathway as resveratrol. “So many people suffer from these diseases,” Schrauwen said of obesity and diabetes. “We're all looking for new targets. I think this is first study to show in humans that targeting this pathway can work.”
Prof Schrauwen, acknowledging that his sample size was small, said he was seeking funding for a larger and longer trial. “This is small, proof of principle study, but the results are so promising that I think it is important that we conduct a bigger study,” he said.
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