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November 10, 2006
Resveratrol Improves Health, Survival in Aged Overweight Male Mice
Resveratrol, a natural compound found in grapes, wines and nuts, was all over the news last week. Overweight aged male mice whose high-calorie diet was supplemented with resveratrol were healthier and lived longer than mice eating the same diet without the supplement. As with many promising compounds researchers have uncovered in the past, however, it’s best to be cautious about what resveratrol will be able to do for people.
Resveratrol is a small molecule produced by some plants in response to stress. It activates a family of enzymes called sirtuins. Studies over the last few years have found that resveratrol can extend the lifespan of yeast, worms, flies and fish. An international group of researchers led by Dr. Rafael de Cabo of NIH’s National Institute on Aging (NIA) and Dr. David A. Sinclair at Harvard Medical School studied the compound in mice, a mammal often used as an experimental model before testing in people. NIA was the primary supporter of the work, with several other entities also providing support.
The researchers placed year-old mice (considered middle-aged) on three different diets for six months: a standard mouse diet, a high-fat, high-calorie diet and a high-fat, high-calorie diet supplemented with resveratrol. They published their results online on November 1, 2006, in the journal Nature. The scientists found that at 60 weeks of age, the high calorie/resveratrol group began to show a clear advantage in survival over the high-calorie group. By 114 weeks (old age for a mouse), 58% of the high-calorie mice had died, but only 42% of the mice eating the same high-calorie diet with resveratrol — a number similar to that of the mice eating the standard diet.
Resveratrol didn’t cause a significant reduction in body weight, but it still produced several changes associated with better health and longer life. For example, the high-calorie diet had about doubled the size and weight of the animals’ livers by the time they were 18 months old, but resveratrol protected the mice taking it from the change. Tests on a rotating device to measure balance and motor coordination showed that the resveratrol-fed overweight mice maintained better motor skills than those on the high-calorie diet alone. The mice eating the diet with resveratrol also had lower blood levels of several factors that, in humans, predict the onset of diabetes.
There weren’t any noticeable toxic effects from resveratrol, either. However, Dr. Richard J. Hodes, director of NIA said, “It should be cautioned that this is a study of male mice, and we still have much to learn about resveratrol’s safety and effectiveness in humans.”