What is resveratrol as a dietary supplement?

Overview

The French diet is high in saturated fat and cholesterol, yet France has one of the world’s lowest rates of heart disease. One theory for this apparent discrepancy is that another major player in the French diet, red wine, protects the arteries of the heart. Another possibility, perhaps even more likely, is that cutting down on saturated fat is less helpful than previously thought.

Resveratrol is a natural antioxidant found in red wine. Antioxidants protect cells in the body from damage by free radicals, naturally occurring but harmful substances that are thought to play a role in cardiovascular disease. Resveratrol is also a phytoestrogen, a substance that mimics some of the effects of estrogen, while blocking others. Soy, another phytoestrogen, is thought to help prevent heart disease and cancer, and resveratrol might have similar effects. However, none of these potential benefits of resveratrol have been documented in any meaningful way, and there is some evidence that resveratrol taken by mouth is broken down by the liver before it enters the bloodstream.

Sources

Resveratrol is not an essential nutrient. It is found in red wine, red grape skins and seeds, and purple grape juice. Peanuts also contain a small amount of resveratrol. Resveratrol supplements are available too.

Therapeutic Dosages

Because no clinical studies have been undertaken to look at the effects of resveratrol, the optimal therapeutic dosage has not been established. Based on animal studies, a reasonable therapeutic dosage might be about 500 milligrams daily.

Therapeutic Uses

Preliminary evidence, such as the results of test-tube studies, suggests that resveratrol may help prevent heart disease and cancer. However, not all studies have been favorable. Furthermore, there is some evidence that resveratrol is immediately broken down by the human liver and therefore does not enter the bloodstream at any significant level. In any case, only double-blind studies can prove a treatment effective, and none have been reported with resveratrol.

Safety Issues

Resveratrol, which has a chemical structure similar to that of the synthetic estrogenic hormone diethylstilbestrol, has estrogenic effects. According to one study, resveratrol might stimulate the growth of breast cancer cells. For this reason, resveratrol should be avoided by women who have had breast cancer or are at high risk of developing it. Maximum safe dosages for children, pregnant or nursing women, or those with severe liver or kidney disease have not been determined.

Bibliography

El Attar, T. M., and A. S. Virji. “Modulating Effect of Resveratrol and Quercetin on Oral Cancer Cell Growth and Proliferation.” Anticancer Drugs 10 (1999): 187-193.

Fulda, S. “Resveratrol and Derivatives for the Prevention and Treatment of Cancer.” Drug Discovery Today 15 (2010): 757-765.

Gullett, N. P., et al. “Cancer Prevention with Natural Compounds.” Seminars in Oncology 37 (2010): 25-281.

Mgbonyebi, O. P., J. Russo, and I. H. Russo. “Antiproliferative Effect of Synthetic Resveratrol on Human Breast Epithelial Cells.” International Journal of Oncology 12 (1998): 865-869.

Walle, T., et al. “High Absorption but Very Low Bioavailability of Oral Resveratrol in Humans.” Drug Metabolism and Disposition 32 (2004): 1377-1382.