Many studies investigating the benefits of red wine suggest that a moderate amount of red wine (one glass per day for women and two for men) lowers the risk of heart attack for people in the middle age, by 20-50%. It is also suggested that alcohol such as red wine may prevent additional heart attacks.
The way in which red wine helps the heart is by raising HDL cholesterol (which is the good form) and lowering LDL cholesterol which is the damaging kind. Further research suggests that it may be beneficial in helping to prevent blood clots and reduce blood vessel damage caused by fat deposits.
All varieties of wine are high in Flavonoid Phenolics which is a potent antioxidant, but red wine in particular has the highest concentration and studies to uncover the health benefits have focused on its Phenolic constituents, particularly Resveratrol, this is a substance found in grape skins and seeds and can be beneficial in raising HDL cholesterol.
Red wine which is fermented with the skins, seeds and twigs tends to contain much larger quantities of the beneficial substances then white wine, which is fermented only from the pressed juice of the grape.
All this research is not new; the discovery was made 20 years ago, starting with reaserch into Polyphenols, the pigment in grape skins.
Going even further back, the idea that wine may be helpful in combating heart disease, started with the observation that people in the burgundy region of France, experience a lower rate of heart dieses then do people in western countries, this is despite the observation that Burgundians generally eat a diet that is rich in cheese and cream; this has become known as the French paradox the observation lead to the suggestion that drinking wine could prevent against heart disease.
Although more research is needed to clarify all the facts, the scientific consensus seems to be that wine and in particular red wine, if taken in moderation has some definite, positive health properties.