Most scientists who study the physiological effects of alcoholic beverages have assumed that wine, like beer or distilled spirits, is a drink whose only active ingredient is alcohol. Because of this assumption, these scientists have rarely investigated the effects of wine as distinct from other forms of alcoholic beverages. Nevertheless, unlike other alcoholic beverages, wine has for centuries been thought to have healthful effects that these scientists—who not only make no distinction among wine, beer, and distilled spirits but also study only the excessive or abusive intake of these beverages—have obscured.

Recently, a small group of researchers has questioned this assumption and investigated the effects of moderate wine consumption. While alcohol has been shown conclusively to have negative physiological effects—for example, alcohol strongly affects the body's processing of lipids (fats and other substances including cholesterol), causing dangerous increases in the levels of these substances in the blood, increases that are a large contributing factor in the development of premature heart disease—the researchers found that absorption of alcohol into the bloodstream occurs much more slowly when subjects drink wine than when they drink distilled spirits. More remarkably, it was discovered that deaths due to premature heart disease in the populations of several European countries decreased dramatically as the incidence of moderate wine consumption increased. One preliminary study linked this effect to red wine, but subsequent research has shown identical results whether the wine was white or red. What could explain such apparently healthful effects?

For one thing, the studies show increased activity of a natural clot-breaking compound used by doctors to restore blood flow through blocked vessels in victims of heart disease. In addition, the studies of wine drinkers indicate increased levels of certain compounds that may help to prevent damage from high lipid levels. And although the link between lipid processing and premature heart disease is one of the most important discoveries in modern medicine, in the past 20 years researchers have found several additional important contributing factors. We now know that endothelial cell reactivity (which affects the thickness of the innermost walls of blood vessels) and platelet adhesiveness (which influences the degree to which platelets cause blood to clot) are each linked to the development of premature heart disease. Studies show that wine appears to have ameliorating effects on both of these factors: it decreases the thickness of the innermost walls of blood vessels, and it reduces platelet adhesiveness. One study demonstrated a decrease in platelet adhesiveness among individuals who drank large amounts of grape juice. This finding may be the first step in confirming speculation that the potentially healthful effects of moderate wine intake may derive from the concentration of certain natural compounds found in grapes and not present in other alcoholic beverages.