Resveratrol is one of many naturally occurring plant chemicals called polyphenols. This important polyphenolic compound is found in grapes, peanuts and blueberries, as well as spruce, eucalyptus and other plants (not all of them edible). Red wine is rich in it, and white wine has some, too. Many reports have called resveratrol the ingredient in wine that appears to protect wine drinkers from cardiovascular disease.
First isolated in 1940, the resveratrol molecule is purported to help or prevent degenerative diseases of aging—everything from diabetes and cardiovascular disease to cancer and Alzheimer's disease. It's also said to combat the effects of aging on a cellular level and have neuro-protective effects. The claims in magazine ads, on TV and all over the Internet are eye-catching. For instance: "Harvard researcher says resveratrol is the Holy Grail of aging research." Research from other prestigious institutions, such as Johns Hopkins, the Salk Institute and the University of California is also often cited to make the case that resveratrol holds the secret to longevity.
Resveratrol: What some studies suggest
Many scientists have been studying resveratrol, and research findings have been tantalizing. Almost 4,000 studies have been done on it, the vast majority of them in test tubes or in animals. More human studies have been published in recent years, though virtually all have been small and preliminary. Resveratrol bioavailability can vary considerably from person to person.
- In studies of yeasts, certain worms, and other small organisms, as well as mice, high doses of resveratrol have lengthened lifespan, but there have been no large, long-term studies in humans yet.
- Studies suggest that resverastrol may help protect against cardiovascular disease, notably by acting like an antioxidant, inhibiting inflammation, stimulating the production of nitric oxide (which helps keep arteries flexible), reducing blood pressure and inhibiting blood platelet aggregation (similar to aspirin). But there's no research showing that supplements actually prevent heart attacks or strokes. It’s true that wine, especially red wine, has heart benefits, but it’s not known to what extent resveratrol is involved in this. On the other hand, good studies have found that resveratrol, under some circumstances, can act like a pro-oxidant and can thus damage cells.
- In a small English study of healthy young people, published in the American Journal of Clinical Nutrition in 2010, resveratrol increased cerebral blood flow in study subjects when they were performing mental tasks. However, this did not result in improved cognitive function.
- A small 2011 study of obese people, published in Cell Metabolism, found that 30 days of resveratrol supplementation resulted in potentially beneficial metabolic changes similar to those occurring during calorie-restricted diets. However, a small study of healthy postmenopausal women, published in Cell Metabolism in 2013, found that resveratrol supplements resulted in no changes in blood pressure, blood cholesterol, glucose tolerance or other measures of metabolic function over the course of 12 weeks.
- And in 2012, investigators found that a leading researcher on resveratrol, Dipak K. Das, Ph.D., of the University of Connecticut, had fabricated data in more than 100 lab studies, which were published in major journals. It’s unclear what impact, if any, this will have on the larger body of resveratrol research.
Many modern medicines come from plants; aspirin is perhaps the best-known example. Still, not all remedies extracted from plants have proven successful. In addition, many nutrients and phytochemicals work best as team players—not as isolated elements to be swallowed in large doses.
Bottom line: Resveratrol is a promising compound, but so far there have been no clinical trials on its effects on diseases and longevity. As a 2011 systemic review paper in the online journal PloS ONE concluded, the published evidence is not strong enough to justify recommending resveratrol beyond the amount from dietary sources—though animal data on the prevention of various cancers, heart diseases and diabetes indicate the need for more human trials.
Many such studies are now underway. The supplements appear to be safe (except for gastrointestinal distress at high doses), but their long-term effects are an open question. No one knows yet what doses are optimal or who would benefit most—or how resveratrol compares to other plant compounds or drugs. Until more is known, get your resveratrol from your diet: grape juice, grapes, blueberries, peanuts and wine.
Originally published October 2009. Updated February 2014.