You may have heard of the "French paradox." The French diet is very high in saturated fat and cholesterol (just think of pate de fois gras and croissants), 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. See the High Cholesterol article and the Antioxidant article for more information.)

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 as well as cancer, and resveratrol might have similar effects. However, as yet 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 before it enters the bloodstream.

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