Q.I heard that red wine can help prevent heart disease. Can I get the same results from drinking grape juice?

A. Several studies show that frequent red wine ingestion offers protection against heart disease and stroke. Presumably this protection is the result of flavonoids in red wine protecting against oxidative damage to LDL cholesterol.

Grape juice also contains flavonoids and has been suggested to offer similar protection to red wine. However, while studies in test tubes do show grape juice flavonoids to inhibit LDL oxidation, a recent human study showed that grape juice does not provide any significant protection. The difference between red wine and grape juice is thought to be due to the fact that the flavonoids in red wine are mainly pure flavonoids (primarily quercetin) while in grape juice the flavonoids are bound to various sugars that may reduce bioavailability. If you are concerned about the alcohol content in the red wine, I recommend using extracts of green tea, grape seed, pine bark, or red wine.