What other health benefits, if any, does alcohol have?
Even as little as one drink a week may protect against ischemic stroke (the most common type). Some research also suggests that moderate drinking may cut the risk of developing dementia, including Alzheimer's disease.
Is wine a better choice than beer or spirits?
It's almost certainly the alcohol that's protective, so it doesn't matter much which beverage you drink. Nevertheless, how you drink the beverage may be important. Beer and wine tend to accompany food—and food slows the absorption of alcohol, which is good. Furthermore, people who drink at meals, especially in the company of others, tend to keep intake moderate. Heavy drinkers usually drink outside of meals. It's true that wine (red or white) contains certain phytochemicals that may protect against heart disease or even cancer—and nonfermented grape juice also contains these compounds.
Beer and spirits, made from grains and other plants, have phytochemicals of their own. Wine may simply seem healthier than other drinks because wine drinkers tend to be better educated and more prosperous than other drinkers, which means they tend to have better diets and better health care.
Isn't it wine that protects the French from heart disease—even though they eat so much cheese, meat and butter?
Wine is only a small part of the picture. This is the famous "French paradox"—the French diet generally includes relatively high amounts of animal fat, but the French have lower rates of heart disease than Americans. Most important, though, the French tend to consume fewer calories and to be more active. And while the French have a lower death rate from heart disease, French life expectancy is only a year longer than that of Americans. In any case, wine consumption has been falling in France for decades, and half of all adults don't drink at all. It would be unwise to conclude from all this that drinking wine will make up for a diet high in calories and saturated fat.
What is "moderation"?
This is a tricky question, and it varies according to your age and sex. The official definition of a "drink" is 12 ounces of beer, four or five ounces of wine, and one and a half ounces of 80-proof spirits. Most people are surprised to learn that these all contain the same amount of pure alcohol, about half an ounce (a little more in the spirits). Moderate intake is no more than one drink per day for a woman, on average, or two drinks for a man. Most studies have found that people who drink this much have the lowest overall mortality rate—lower than nondrinkers, occasional drinkers and heavy drinkers.
But, in fact, the studies diverge. The new one described in the first paragraph found higher intakes beneficial. Other studies have found lower intakes to be best. Moreover, if it's healthy for a man to have up to 14 drinks a week, can he drink six on Friday and six on Saturday and abstain the rest of the week? Probably not—binge drinking appears to be harmful.
What about body size: is it okay for a tall man who weighs 200 pounds to drink more? What about an athletic woman that same size? Or a man 5'4" and thin? Even one drink can be too much for a very small woman. Obviously, size can sometimes trump gender, or at least confuse the issue. And age comes into play, too, since alcohol affects older people more (see below).
Another problem: Portion inflation occurs not only on your plate, but in your glass. Many bars and restaurants do not serve standard-sized drinks, and what's served as one drink actually may be the equivalent of two or even three. Most people are pleased to be served generously—but you can't take half your drink home in a doggy bag, as you can your entree. If you ordinarily serve wine or spirits at home without measuring, it might be instructive to measure and see how close you come to the standard serving sizes. That will give you some idea, too, of how much you're getting in a restaurant.
Why are the guidelines different for men and women?
Alcohol affects men and women differently. A woman will get more intoxicated than a man from the same amount of alcohol. Women tend to be smaller, with a lower percentage of water and a higher percentage of body fat. Since alcohol is distributed through body water and is more soluble in water than in fat, blood alcohol concentrations (BACs) in women tend to be higher.
In addition, the stomach enzyme that breaks down alcohol before it reaches the bloodstream is less active in women. Alcohol also carries additional health risks for women, since heavy drinking boosts the risk of osteoporosis. Women are more prone to suffer liver damage from heavy drinking, too.