Resveratrol has been touted as an antiaging therapy since 2003, when David Sinclair, a Harvard Medical School pathologist and co-author of the current study, found that the life span of yeast could be extended by up to 60 percent when treated with the molecule. The same effect has been replicated in worms, flies and fish. In the case of the obese mice, Sinclair observes, resveratrol increased insulin levels while decreasing glucose levels, resulting in healthier liver and heart tissue when compared with obese mice that did not receive treatment. "After six months, resveratrol essentially prevented most of the negative effects of the high-calorie diet in mice," says study co-author Rafael de Cabo of the National Institute of Aging (NIA).
Three groups of middle-aged mice (about a year old) were studied: one group ate a normal diet, in which fewer than 30 percent of calories came from fat, while two others were fed high-calorie diets in which 60 percent of the calories came from fat. Of the two groups on the high-fat diets, one received resveratrol. After 114 weeks, 58 percent of the normally fed mice and the resveratrol group were still alive, compared with only 42 percent of the untreated, high-calorie-intake mice. Sinclair reports that resveratrol reduced the risk of death from a high-calorie diet by 31 percent, leading to an increase in life span of 15 percent thus far. More accurate numbers will be available when all the mice pass away. "We are around five months from having final numbers," Sinclair notes, "but there is no question that we are seeing increased longevity." The researchers also note that the resveratrol-treated mice not only live longer than their untreated counterparts, but have more active lives, too--their motor skills have actually improved as they have aged.
The researchers believe resveratrol confers its effects by activating the enzyme SIRT1, which is known to play a part in life extension. When the nonmammalian analog to SIRT1, Sir2, is blocked in lower order species like fruit flies, the healthy effects of low-calorie diets, versus high-calorie diets, are neutralized. Sinclair thinks that these mouse models indicate that resveratrol may be effective in preventing age-related diseases in humans, like cancer, heart disease and type 2 diabetes.
Reservatrol has previously been shown to prevent damage to liver tissue, says Matt Kaeberlein, a pathologist at the University of Washington; the compound could be staving off age-related diseases by keeping the liver healthy. But, he notes that more work needs to be done to determine if resveratrol affects other parts of the body as well. "There are several other compounds that are undergoing testing," Kaeberlein notes, explaining that the NIA is looking at about a dozen other antiaging treatments. "If resveratrol turns out not to be as wonderful as we all hope it will, it's not the last hope." Even if resveratrol does turn out to be a miracle drug, a wine glass would probably not be the preferred delivery method. According to Kaeberlein, it would take over 300 glasses of wine per day to equal the amount of resveratrol fed to the obese mice in this study.