The World's Healthiest Foods

Polyphenols in Grape Skins Help Prevent Heart Disease

Researchers have learned more about the beneficial effects of moderate consumption of red wine on heart disease, and their recent findings may help explain the so-called French paradox: the fact that the French have relatively low rates of heart disease despite a national diet that features creamy cheese and rich desserts.

Investigators in the UK found that phenolic compounds in grape skins (and therefore present in red wine) inhibit protein tyrosine kinases, a group of enzymes that play a key role in cell regulation. Compounds that inhibit these enzymes also suppress the production of a protein that causes blood vessels to constrict, thus reducing the flow of oxygen to the heart. This protein, called endothelin-1, is thought to be a key contributing agent in the development of heart disease.

These most recent findings add support the results of earlier studies suggesting that a moderate intake of red wine-one to two glasses per day with food-may help lower the risk of heart disease. Earlier studies had focused on the antioxidant properties of the polyphenols in grapes and thus their ability to quench blood vessel-damaging free radicals. This latest study has revealed an additional mechanism by which phenols' in one of the World's Healthiest Foods, grapes, provide heart-protective benefits.

Researchers based their findings on experiments with cow artery cells treated with alcohol-free extracts of various red, white and rose wines, and also evaluated an extract of red grape juice. Grape skin not only provides red wine with its color, but also contains the highest concentration of polyphenols; other alcoholic beverages do not contain these compounds. The alcohol-free red wine had the strongest inhibitory effect on endothelin; red grape juice also inhibited endothelin production, but much less than the alcohol-free red wine.

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Reference: Nature, December 20/27, 2001;414:863-864.