So you've been feeling virtuous quaffing red wine, nibbling on dark chocolate and popping grapes, thinking you're reaping the life-extending, disease-fighting, health-promoting benefits of resveratrol. You'll need to think again, suggests a new study, which finds that high levels of resveratrol consumed as part of a regular diet are not linked to lower levels of cancer, cardiovascular disease or inflammation, and do not appear to prolong life.
The research was conducted on the senior population of two villages in the Chianti region of Italy — 783 men and women 65 and older whose health and resveratrol intake was tracked from 1998 to 2009. The study was published this week in JAMA Internal Medicine.
Avoiding the pitfalls of asking study participants to record or recall their daily intake, the researchers regularly gathered specimens of subjects' urine and tested them for levels of resveratrol metabolites. Fewer than 1 percent of the study population took vitamin, mineral or herbal supplements of any kind, so researchers could be pretty sure that byproducts of resveratrol were the result of food and drink consumed, not from pills. As might be expected in one of Italy's most prolific wine-producing regions, red wine was a regular feature in most of the subjects' daily diets.
Of the study's 783 men and women, just over one-third died during the nine-year study. About 27 percent of those healthy to begin with developed cardiovascular disease, and 4.6% developed cancer. But whether a study participant consumed high levels of resveratrol or none at all, the study revealed no differences in rates of cancer, cardiovascular disease, death or inflammation.
Researchers have long suspected that it would take a lot more resveratrol than can be consumed in food to influence such surrogate measures of health and longevity as C-reactive protein, a marker of inflammation, or glucose control and insulin sensitivity.
Other studies finding health benefits to resveratrol supplementation have been conducted on people with health conditions, including obesity and diabetes. Though a typical proportion of participants in the current study already were sick when they were recruited, they were a small minority. Most of those in the Chianti study were aging but healthy. And for them, consuming resveratrol didn't help.
So, as with many agents found in nature or synthesized in a lab, resveratrol is probably helpful only in doses higher than can practically be consumed (and safe in doses that have not yet been determined). And resveratrol may be better at treating disease than it is at preventing it.