The chemical compound resveratrol, found in grape skins and red wine, continues to be the focus of groundbreaking research by health experts. In the latest study, released Thursday, a team of researchers said the compound helps keep the bones, eyes, kidneys, heart and other muscles in mice healthier as they age, though without increasing the animals' overall lifespan.
The conclusions of their experiment were published on the website of the medical journal Cell Metabolism. The study, co-authored by Rafael de Cabo of the National Institute on Aging (NIA) and noted resveratrol researcher David Sinclair of Harvard Medical School, found that resveratrol provides cardiovascular benefits, greater motor coordination, reduced cataracts and even greater bone density and kidney function when administered to mice.
"From a health point of view, the quality of life of these mice at the end of their days is much better," said de Cabo, who adds that resveratrol may one day extend productive independent life in humans.
The study finds that resveratrol works in a way similar to caloric restriction (CR), a process where one's diet is reduced by 30 to 40 percent fewer calories, according to de Cabo. CR is a form of dietary restriction that has well-documented health benefits in mammals—previous research has found that a CR diet can slow aging in rodents by as much as 30 percent by triggering anti-aging activities in cells. The purpose of the study was to look at resveratrol as a potential alternative to CR, which is not only an unpopular therapy but "may pose a significant risk to the frail, critically ill, or the elderly," the study states.
Several previous studies have found health benefits of resveratrol in mammals. German researchers found the red wine chemical cuts fat in human cell lines. And an earlier study by Sinclair found that resveratrol helps to extend the lifespan of obese mice. According to the new study, the latter finding posed a two-part question to researchers: "Can resveratrol improve the health of non-obese mice and, if so, is this due to an ability to mimic the effects of dietary restrictions?"
To find an answer, the researchers separated the mice into several groups. Some were allowed to feed at will. Other groups were kept on restrictive diets, while others were fed high-calorie diets. Some of the groups were also given various sized doses of resveratrol.
Over time, a trend emerged: mice on either CR or resveratrol diets tended to remain healthier than mice on standard diets without resveratrol. For instance, at two years of age, standard diet mice could only stay on a treadmill for an average of just over two minutes. Mice on resveratrol, on the other hand, could stay an average of nearly three minutes, an indication of better balance and endurance.
After the mice died naturally, the scientists conducted extensive biopsies, including genetic testing. The mice on resveratrol showed multiple health benefits, including greater bone mineral density, less vascular and kidney dysfunction and fewer instances of cataracts. On a genetic level, the changes both CR and resveratrol produced were remarkably similar, the study states.
"Our experiments looking at DNA microarrays are telling us that yes, we are looking at a molecule that is mimicking the effects of caloric restriction at the genetic level," said de Cabo. "The development of [such] drugs is a hot area in our fields now, with a very promising future."
Indeed, Sinclair is a research consultant with a company called Sirtris Pharmaceuticals, which was sold to GlaxoSmithKline for $720 million earlier this month.
Sinclair adds that the results of the current research caught him by surprise. "Usually, you focus on slowing down or ameliorating one disease at a time," he said. "In this case, resveratrol influences a whole series of seemingly unrelated diseases associated with aging." Sinclair adds that the results seen in the experiment may have an even greater impact in humans, perhaps even extending lifespan, as mice usually don't die as a result of the conditions resveratrol eased in the study.
However, the study warns that resveratrol may have a toxic effect in higher doses. And de Cabo adds that the amounts of resveratrol used in the study are unobtainable through one's natural eating and drinking habits. "If the resveratrol doses that we used in mice are translatable to humans, it would have to be with a pill," he said, adding that "red wine is still a great source of resveratrol and probably one of the most common sources for most people."