The Secret Powers of Resveratrol

Antioxidants in red wine and chocolate did not curb heart disease or cancer in older adults

(RxWiki News) The health benefit of red wine, grapes, chocolate and a few other foods is a hot topic. But was is fact or fiction? A new study doubts the health benefits of a substance called resveratrol.

Cases of heart disease or cancer did not significantly decline in people aged 65 and older who consumed resveratrol through their diet, according to a new study. That study also concluded that resveratrol did not extend their lives.

These researchers concluded that no studies have soundly proven the benefits of resveratrol and that claims about resveratrol's benefits wrongly rest on a 1992 study of French people.

That study attributed low rates of heart disease among French people, who tended to eat food high in fat, to their wine consumption.

Resveratrol is a polyphenol, which plants make. Based mainly on results from testing resveratrol in overfed mice and other animals, and on a disputed study of French wine drinkers, some have suggested that resveratrol can prevent oxidation. Oxidation is a process that makes food harm rather than help the body.

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Richard Semba, MD, MPH, of Johns Hopkins University School of Medicine and Center for Human Nutrition in Baltimore, MD, was this study’s lead author.

Dr. Semba and his research team sought to investigate the effects of resveratrol consumption on 783 men and women residing in two villages in Tuscany, Italy, a wine-producing area, and enrolled in the Aging in the Chianti Region study from 1998 to 2009. All study participants were at least 65 years old. The group's average age was about 75. 

The researchers tested levels of resveratrol in study participants' urine after three years, six years and nine years. Despite varying levels of resveratrol showing in study participants' urine, the researchers wrote that "dietary resveratrol from Western diets in community-dwelling older adults does not have a substantial influence on inflammation, cardiovascular disease, cancer or longevity.”

That reality was reflected as follows: Of the 639 study participants who did not have heart disease but who were consuming varying amounts of food or drink containing resveratrol, 174 persons (27.2 percent) developed heart disease during the nine years that researchers tracked participants.

Of the 734 study participants who were cancer-free at the start of the study, 34 persons (4.6 percent) developed cancer during the nine years of tracking. Of the initial 783 study participants, 268 persons (34.3 percent) died during the same nine-year period.

This new study of Italians also challenged the value of taking resveratrol supplements.

"Although annual sales of resveratrol supplements have reached $30 million in the United States alone, there is limited and conflicting human clinical data demonstrating any metabolic benefits of resveratrol, and there are no data concerning its safety in higher doses or for long-term supplementation in older people, who often ... are taking multiple medications," the researchers wrote.

This study was published online May 12 in JAMA Internal Medicine.

The National Institutes of Health and National Institute of Aging in the United States and the Italian Ministry of Health funded this research.

These researchers reported that they had no financial investments or other ethical conflicts that might affect study design, outcomes and analysis.