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"In the elderly, many of the disorders that occur with aging occur because of muscle weakness," Helfand said. "This makes you wonder what would happen if you took an older individual and revved up their mitochondria with resveratrol. You could imagine that it could have a profound positive effect on their health."

Auwerx also wondered whether the substance might be abused by professional athletes. "That could be the illicit use of these compounds -- as performance boosters," he said.

In addition to the mouse experiments, the researchers also produced evidence supporting the theory that SIRT1 plays a key role in longevity in humans in an accompanying analysis of 123 Finnish adults. The subjects born with certain variations of the SIRT1 gene had faster metabolisms, naturally burning energy more efficiently, indicating the same pathway works in humans, too.

"We've all seen people who are thin no matter what they eat or do -- that have good metabolisms versus bad. This may help explain that," said Christoph Westphal, chief executive of Sirtris Pharmaceuticals in Cambridge, Mass., which sponsored and helped conduct the study as part of its efforts to develop drugs based on the approach.

The company is testing a potent version of resveratrol on diabetic humans and hopes to eventually test it and similar compounds as a treatment for a variety of diseases.

"We are targeting a gene that controls the aging process," Westphal said. "Many diseases have a link to the aging process. So these kinds of drugs clearly have the potential to treat several diseases of aging. It's very exciting."

Other researchers said the new work was interesting, but they remained cautious, particularly about making the link to SIRT1.

"I think that's part of the story but that it would be a mistake to think that's all that's going on," said Matt Kaeberlein of the University of Washington. Other biological pathways also probably play important roles in the aging process and diseases of aging, he said.