Resveratrol -- a substance found in red wine, grapes and chocolate may not add years to your life, and it doesn't appear to reduce the risk for heart disease or cancer either, according to new research.
"When it comes to diet, health and aging, things are not simple and probably do not boil down to one single substance, such as resveratrol," said study lead researcher Dr. Richard Semba, a professor of ophthalmology at Johns Hopkins University School of Medicine in Baltimore.
The findings also cast doubt about taking resveratrol supplements, he said.
"Perhaps it brings us back again to rather tried and true advice of diet -- Mediterranean-style -- and regular aerobic exercise for healthy aging," said Semba.
The report was published May 12 in the online edition of JAMA Internal Medicine.
Red wine and chocolate have been shown to have beneficial effects on health, and these benefits were attributed largely to a single substance -- resveratrol. Resveratrol has been credited as being responsible for the so-called "French paradox," in which even a diet high in cholesterol and fat can be healthy if it is accompanied with red wine, the researchers explained.
For the study, Semba's team followed nearly 800 men and women 65 years or older who were part of the Aging in the Chianti Region study from 1998 to 2009 in two villages in Italy.
These folks had a diet rich in resveratrol, the researchers note.
To see if resveratrol in the diet could lower the risk of cancer, heart disease and death, the researchers measured traces of products left by resveratrol in the participant's urine.
During the follow-up period, 268 people (34.3 percent) died; 174 (27.2 percent) developed heart disease and 34 (4.6 percent) developed cancer, the researchers found.
When the researchers looked at the resveratrol levels, they found no significant differences in the rate of death from those with the lowest levels to the highest. They also found no association with higher levels of resveratrol and a lower risk of heart disease or cancer. In fact, the lowest rates of heart disease were in people with the lowest levels of resveratrol.
The bottom line, according to Semba, is that dietary resveratrol didn't translate into fewer deaths, cancers or heart problems.
Samantha Heller, a senior clinical nutritionist at New York University Medical Center in New York City, said, "A quick search of the medical literature finds that many of the current studies done with resveratrol have been done in test tubes or in animals. This study, in humans, seems to indicate that an increased consumption of foods that contain resveratrol, such as red grapes and wine, does not affect long-term health over nine years. It may be that the effects of dietary resveratrol are not evident in this time period."
Resveratrol is famous for giving the green light to people who want to consume alcohol, Heller said.
"Many of my patients ask me, 'Should I start or continue to drink wine? It's heart-healthy, isn't it?'" she said.
One of the reasons red wine in particular is considered heart-healthy is because of its resveratrol content, Heller said.
However, alcohol in any form can be toxic when one drinks too much. "While some studies indicate that regular consumption of red wine may have health benefits, the reality is that many of us drink too much alcohol, which over time can adversely affect liver and brain function, as well as blood sugar and weight," Heller said.
Fruits and vegetables are loaded with a lot of phytochemicals (including resveratrol), vitamins and minerals that work together to help promote health and fight disease, she said.
"Red grapes, peanuts, berries and other foods containing resveratrol are great to include in your diet; however, since we eat foods and not single nutrients or compounds, we must remember to look at the whole picture of what we eat and how we choose to live," said Heller.
Current research and common sense suggests that a more plant-based, whole-food diet and regular exercise have long-term health benefits, Heller said.
"This is not to say that a glass of wine now and then is not a healthy option. The American Heart Association recommends an average of one to two drinks per day for men and one drink per day for women," Heller said. (A drink is one 12-oz. beer, 5 oz. of wine, 1.5 oz. of 80-proof spirits, or 1 oz. of 100-proof spirits, according to the National Heart, Lung, and Blood Institute).