In another study that suggests red wine (or compounds found within) may be good for your health, researchers found that old, obese mice that were fed a high-fat diet plus the compound resveratrol were healthier and lived longer than their counterparts that didn't get resveratrol.

Resveratrol is a naturally occurring compound found in red wine, grapes and nuts. Other studies have found that resveratrol can extend life in yeast, worms, fruit flies and fish. It appears to be associated with anti-aging and preventing the effects of diseases of aging, such as diabetes, cancer and dementia.

"Resveratrol extends the lifespan of every species we have fed it to," said lead researcher David Sinclair, an associate professor of pathology at Harvard Medical School. "We are now showing that this is also possible for mice on a high-fat diet," he added.

The study findings are published in the Nov. 2 issue of Nature.

The researchers found that, among the overweight mice, resveratrol reduced the negative impact of being obese. When the mice were 60 weeks old, those mice receiving resveratrol showed a three- to four-month increase in survival, compared to mice not receiving the compound.

By 114 weeks, when the mice reached old age, more than half of the animals on a high-fat diet alone had died, compared to less than one-third of those receiving resveratrol.

"The goal is to turn this knowledge into drugs that would treat diseases of aging, like diabetes, heart disease and Alzheimer's," Sinclair said. "It's hard to know how far we can go with this technology. We are in new territory. We have never had a molecule that can achieve these effects in such diverse animals."

Resveratrol works by activating an enzyme called SIRT-1, which is found in all life forms and appears to control aging, Sinclair said. "It's triggering ancient pathways that counter diseases and aging," he said.

In addition, resveratrol stabilizes blood sugar and other effects of obesity. Sinclair speculated that a drug could be developed that would protect against diabetes, cancer, Alzheimer's and heart disease.

But, Sinclair noted, the results of these studies are preliminary. "I don't recommend that people go out and just take products that claim to have resveratrol in them," he said.

Co-researcher Rafael de Cabo, an investigator at the U.S. National Institute on Aging, cautioned, "This is only a mouse study. We have to repeat it.

"The data is amazing," he added. "But every time you open a door in research, we find a thousand new doors, so there are a lot of questions still to be answered."

There are currently two human trials testing the value of resveratrol. One, at the University of California, includes patients with colon cancer. The other one, sponsored by Sirtris Pharmaceuticals, includes diabetes patients. Sinclair is one of the founders of Sirtris.

"We have taken an improved form of resveratrol into a human diabetes trial," said Sirtris CEO Dr. Christoph Westphal. The trial is testing whether the new drug is safe and whether it will control blood sugar. The researchers expect to have results in late 2007, Westphal said, adding, it will be at least four to five years before resveratrol drugs might be available.

One expert thinks that while the results of this study are impressive, there's a long way to go before resveratrol is proven safe and effective.

"As provocative as these findings are, it is not yet time to start popping resveratrol supplements, or rely on the compound as an alternative to healthful eating, physical activity, or attempts at weight control," said Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine.

Time and again, promising findings in test tubes and mice have failed to translate into human benefit, Katz said. "The list of such disappointments includes almost every nutrient that has at one time or another captivated the public's imagination, including, over recent years, beta carotene, vitamin C, and vitamin E."

This research should make on-going study of resveratrol a priority, Katz said. "While hoping that the promise of benefit without harm is fulfilled in people, I would advise against leaping to that conclusion until the evidence comes in," he said.