No doubt, you’ve heard of the “French paradox,” the observation that despite a diet dripping with high-fat pâtés and croissants, the French suffer less heart disease than do Americans. The French credit red wine for this — a somewhat controversial claim because studies show that people who drink any alcohol in moderation (one to two beers, cocktails, or glasses of wine a day) suffer less heart disease than abstainers or those who drink more. And at the same time, research has linked even moderate alcohol consumption with other health problems, such as breast cancer. Now this tempest in a wineglass has been resolved. While alcohol in general reduces the risk of heart disease because it increases the level of high-density lipoproteins (HDL) — the so-called good cholesterol — in the blood, red wine contains something other alcoholic drinks do not: specific flavonoids that help prevent the formation of blood clots that trigger heart attacks. This finding is good news for those who cannot or should not drink alcohol. Nonalcoholic purple grape juice contains the same flavonoids as red wine, and drinking three glasses a day can reduce blood coagulability by about 40 percent. — M.C.