Scientists have provided the strongest evidence yet that the anti-aging benefits of calorically restricted diets can be duplicated -- minus the near-starvation -- by a pill.

In a study published today in Cell Metabolism, mice given resveratrol -- the first of an eagerly-anticipated class of longevity drugs -- enjoyed dramatically improved health, even when they started taking the drug late in life.

Resveratrol didn't extend the lives of normal mice, but it did protect them from the ravages of time. The rodents had stronger hearts, clearer eyes, more limber muscles and firmer bones. Closer analysis revealed the same cell-level changes produced by caloric restriction, an extreme form of dieting that consistently lengthens the lives of lab animals but is impractical, if not dangerous, for people.

"For the first time, we can mimic caloric restriction in an otherwise healthy animal," said study co-author David Sinclair, a Harvard University biologist and co-founder of Sirtris Pharmaceuticals. "That's been the goal of the field for decades. We didn't know it was possible to let an animal eat whatever it wants, but still get the benefits. We now have evidence."

Regardless of mouse weight and diet, resveratrol worked wonders. At two years of age, or the mouse equivalent of senescence, the mice were more coordinated than their non-dosed counterparts. Their bones were thicker and stronger, their eyes free of cataracts, their hearts beating strong. At the cellular level, tissues displayed gene-level changes almost identical to those produced by caloric restriction.

Sirtris Pharmaceuticals has already started clinical trials of resveratrol and a more-refined sirtuin activator. In June they were purchased for $720 million by Glaxo Smith Kline, signaling the seriousness with which academics and the pharmaceutical industry views the field.

"You've got to take aging research seriously if a company is willing to put down three-quarters of a billion dollars on it," said Sinclair.