Calories and Longevity
SRT501 and resveratrol are believed to work by triggering a physiological state like that achieved through calorie restriction. Scientists already know that calorie restriction—eating about 30 percent less than what your body needs to maintain a normal weight, while still getting enough nutrients—allows mammals to slow aging and delay age-related diseases like cancer, heart attack, stroke, diabetes, and dementia. And studies have significantly prolonged the lives of worms, flies, and rats through calorie-restriction diets. Since resveratrol has been found to increase the life spans of several lower organisms, scientists have hypothesized that the molecule may mimic the healthful effects of calorie restriction in humans, but without the hunger. That’s an enticing prospect for people unable or unwilling to put themselves on such a harsh diet.

In some of those lower organisms, the data suggest that resveratrol and calorie restriction both work by activating proteins called sirtuins. But it’s still unclear whether the connection holds in higher organisms, like humans. Studies of mice are encouraging, though, when it comes to
type 2 diabetes. A 2006 study found that resveratrol improved the health and extended the lives of mice on a high-calorie diet. Baur, the study’s lead author, says resveratrol improved insulin sensitivity, which could help ward off diabetes by keeping blood glucose levels under control. Another study found that higher doses of resveratrol could trigger weight loss in mice. For people with type 2 diabetes, shedding pounds can make blood glucose control easier and reduce the risk for complications like cardiovascular disease.

In a follow-up study last year, Baur and colleagues found that unlike calorie restriction, resveratrol did not extend the lives of middle-aged mice on a normal diet. “There is something calorie restriction does that we were missing for sure [with resveratrol],” says Baur. Yet these mice were healthier in old age, as resveratrol reduced osteoporosis, cataracts, and vascular dysfunction while improving motor skills. Plus, the researchers found evidence that resveratrol induced biochemical responses like those triggered by calorie restriction. Baur’s current research is looking beyond resveratrol for agents that could mimic all the benefits of calorie restriction.

The amount of resveratrol used on these mice is far more than a person could get from just drinking wine. A human would have to down something like 1,000 bottles of red wine a day to even get in the ballpark. Nonetheless, the levels reached in mice are roughly achievable in humans, says Baur, by taking dietary supplements. However, Baur doesn’t recommend supplements because, unlike medications, they are not regulated by the Food and Drug Administration, their efficacy is unproven, and their purity and safety aren’t assured.