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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.
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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.”
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