Studies comparing alcohol intake and ischemic heart disease have shown either an inverse relation or a U-shaped curve in which the equivalent of two drinks per day of any kind of alcohol is associated with a decreased incidence of coronary disease compared with no drinks, while higher doses result in an increased risk of infarction and stroke. The cardioprotective effects of most alcoholic beverages are probably due to an elevation of high-density lipoprotein and the ability of alcohol to prevent platelet aggregation and increase fibrinolysis; however, there is an increased favorable effect from red wine. The unique cardioprotective properties of red wine reside in the action of flavonoids which are minimal in white wine (with the exception of champagne). The best researched flavonoids are resveratrol and quercetin, which confer antioxidant properties more potent than alpha-tocopherol. Grape juice has about half the amount of flavonoids by volume as red wine.