A study has shown that a substance found in the skin of red grapes has anti-aging properties that protect the heart, bones and eyes from the ravages of old age.

Resveratrol, an organic compound found in grapes, nuts and a variety of other plant foods, significantly slows the rate of aging in laboratory mice when given in large enough doses over a long period, although it does not actually prolong their lives.

However, the study did not show that resveratrol actually extended life, only that it improved the quality of life, Rafael de Cabo, of the U.S. National Institute of Aging, said. He took part in the study published in the journal Cell Metabolism.

One finding was that resveratrol appeared to counteract the changes to the heart and cardiovascular system associated with aging and obesity, as well as boosting the density and mineral content of bone, which could help to combat the onset of osteoporosis.

Mice fed resveratrol were also less likely to develop cataracts in their eyes compared with mice that were not given the dietary supplement.

The scientists also found resveratrol stimulated the same genes that appeared to be involved in extending a mouse's life when living on a calorie-restricted diet.

"From a health point of view, the quality of life of these mice at the end of their days is much better. It suggests that resveratrol may extend productive, independent life, rather than just extending life span," de Cabo said.

"We found that while quality of life improved with resveratrol, the compound did not significantly affect overall survival or maximum lifespan."

The scientists believe resveratrol works by mimicking the effects of a calorie-restricted diet, known from animal studies to prolong life and stimulate anti-aging mechanisms in the body, which help to prevent tissues from being damaged or degraded through wear and tear.

Previous research has indicated resveratrol has important health benefits, but scientists are sceptical red wine contains enough of it to be beneficial. Instead, they are working on the idea that a purified form could be given as a dietary supplement.

David Sinclair, of Harvard Medical School, said, "I was most surprised by how broad the effects were in the mice. Usually, you focus on slowing down or ameliorating one disease at a time. In this case, resveratrol influences a whole series of seemingly unrelated diseases associated with aging.

"We are learning a great deal about how resveratrol affects the health and survival of mammals. Continued study may eventually point the way to new medicines to treat diseases of ageing," he concluded.

Resveratrol has been shown to extend the lives of yeast, worms, flies and fish, as well as improving the health and chances of survival of obese mice fed a high-calorie diet.

The scientists believe that if it has a similar effect on humans, it could be an important weapon in the fight against heart disease, osteoporosis and other ailments associated with aging.

From the July 7, 2008, Prepared Foods e-Flash