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R. Curtis Ellison, MD - Professor of Medicine at Boston University School of Medicine and director of the school's Institute on Lifestyle & Health.
The health effects of wine and alcohol in general depend both on how much you drink and your drinking patterns. A number of recent studies have better defined what is the healthiest pattern of alcohol consumption. It may come as a surprise to some, but because many of the beneficial effects of alcohol are transient (lasting only 24 hours or so), the consensus is that if you drink moderately, the best pattern is to do so every day.
The US government defines moderate drinking as no more than 2 drinks per day for men and no more than 1 drink per day for women. Other countries have somewhat higher limits in their definitions of "moderate". But all such guidelines are more political decisions rather than scientific ones. If we look at results from epidemiologic studies, we usually see the maximum health benefits at about 1 or 2 drinks per day for both men and women. However, the net health effects of alcohol consumption usually remain beneficial (lower risk than that of abstainers) for heart disease and for total mortality among people drinking more, up to 4 to 5 drinks per day.
In most studies, 1 drink equals a 5 ounce serving of wine, 12 ounces of beer, or a 1.5 ounce shot of spirits such as vodka or whiskey. Each of these drinks contains between 10 and 15 grams of alcohol.
A word of warning about the number of drinks: not everyone has the same tolerance for alcohol. Many factors affect the amount that an individual can safely consume. These include the following: a) difference in body size; b) gender, women generally can tolerate less alcohol than men because their muscle mass tends to be less and they have more fat, which metabolizes alcohol less efficiently, and women tend to have lower levels of the key enzymes that burn up alcohol; c) the rate of intake, wine should be sipped, not gulped; d) whether or not the beverage is consumed with food; and especially, e) generic factors.
However, most people can tolerate at least a few ounces of wine a day, or similar small amounts of other beverages. Some studies show that people who regularly take in just one-half of a typical drink per day show many of the health benefits that are associated with alcohol consumption. We could say that, except for certain people with contraindications to drinking any alcohol whatsoever, this might be considered the minimum daily amount of wine for optimal health.
But just as important as how much you consume is your pattern of drinking. Binge drinking, defined as 5 or more drinks in a short period of time, can carry serious risks. A Copenhagen, Denmark study recently reported that for men who averaged 14 to 21 drinks per week, those who spread out their drinking over 5 to 7 days had a more than 50 percent lower risk of dying during the following period of the study than those who consumed the same amount in only one or two days (weekend only drinkers). Other studies are reporting the same results. The message is clear: if you are a drinker, you should have a little every day; you cannot save it up for the weekend.
While data are still not conclusive, recent studies suggest that it is healthier to consume your wine with food. This may be due to the fact that your blood-alcohol level, which is associated with intoxication and other adverse effects, rises only one-half as high when a given amount of alcohol is consumed with food. But it may also be because wine has favorable effects on the body's absorption of antioxidants in the food and helps the body metabolize fats more efficiently.
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Many of the health benefits associated with moderate drinking are derived primarily from alcohol, which is of course found in beer, spirits, and wine. However, wine also contains polyphenols and other chemical elements that are not present, or at least not present in the same concentrations, in the other alcoholic beverages. Some of these elements may confer additional benefits and increase protection against other health risks. In looking at current scientific evidences, it appears that wine drinking can play a role in preventing, or at least in reducing the risk of, a wide range of health hazards. Some of these recent studies focus on the benefits of alcohol only, while others focus on the added benefits of wine in particular.
Heart Disease & Stroke
People who consume alcoholic beverages moderately have a much lower risk of coronary heart disease than do abstainers or abusers. This is true no matter where they live, including the places such as Japan and China that traditionally have low rates of heart disease. And for heart disease, it appears that it doesn't matter what people drink. There has been an amazing consistency among reports over the past dozen years: Whether it beer in Germany, sake in Asia, or wine in France or Italy, moderate drinkers have many fewer heart attacks than nondrinkers in the same population.
The same goes for strokes. The most common type of stroke, referred to as ischemic, is caused by atherosclerosis (plaque buildup in the arterial walls), which also causes coronary heart disease. The effect of alcohol on these ischemic strokes is the same as for heart attacks: Moderate drinking is associated with a marked reduction (often 30 percent to 50 percent) in risk. The same goes for congestive heart failure, peripheral vascular disease and other consequences of atherosclerosis.
A small percentage of strokes in the United States (about 10 percent) result from a different cause, a hemorrhage into the brain. Many studies show that any consumption of alcohol causes a slight increase in the risk of hemorrhagic strokes. But one of the largest and best-implemented US studies by Klatsky and associates recently reported that an increase in risk for hemorrhagic stroke starts to appear only for people who average more than 5 drinks a day; there was no increase in risk of hemorrhagic stroke for lighter drinkers.
Important new findings in the past decade have given us a much better insight as to why there are fewer cases of heart disease and strokes among moderate drinkers. An increase in HDL cholesterol (the "good" cholesterol that picks up excess fat in the blood and carries it to the liver to be metabolized) seems to be the single most important factor; since this increase results primarily from the alcohol itself, the effect is similar for those who consume beer, wine, or spirits.
But scientists have now identified dozens of additional mechanisms of protection, some found for alcohol itself, and some that are due to other substances (mainly polyphenols) present in wine and certain beers. Among these mechanisms are: effects on platelets and other coagulation factors that lower your risk of forming a clot in an artery; substances that quickly dissolve any small clots that form in the arteries; effects on a variety of genetic and hormonal factors that stimulate the lining of the artery to prevent the formation of plaques that lead to obstruction; and even a turning off or turning on of certain genes that results in less obstruction within arteries. With wine, you are getting the full package of protective agents against cardiovascular disease, as you have both alcohol and high levels of these important polyphenols.
Diabetes
Diabetes is becoming increasingly more common, and is a major risk factor for heart attacks and strokes. While obesity increases your risk, alcohol and polyphenols from wine have favorable effects on glucose metabolism and insulin sensitivity, and numerous observational studies from around the world have shown that diabetes occurs less commonly among moderate drinkers than among abstainers. In a recent review of the literature, Howard and Colleagues reported that with the intake of 1 to 3 drinks per day, the risk of developing diabetes was reduced by 33 to 56 percent; among diabetics, the risk of coronary heart disease was reduced by 34 to 55 percent. Further, these investigators found that moderate alcohol intake did not interfere with the effects of the medications commonly used for diabetes.
Davies and Associates carried our clinical trial among non-diabetic women, sequentially giving them no alcohol or 2 typical drinks per day. They demonstrated that the alcohol significantly reduced the women's insulin levels and insulin sensitivity, both of which would reduce their risk of diabetes; this was seen both in lean and obese women.
Alzheimer's & Other Dementia
Several excellent studies have documented that elderly people who are moderate drinkers, in comparison with nondrinkers, tend to perform better on tests of memory and cognitive functioning. In these studies, moderate drinkers have a lower risk of developing dementia. Some of these studies have shown that drinking beer, wine, or spirits can protect against developing the disease, but studies from France and Denmark have seen this protection only for consumers of wine. The mechanism for such protection from wine or alcohol is not known, but may relate to the prevention of atherosclerosis in the blood vessels that supply the brain and may be due to the fact that inflammation (a possible factor in Alzheimer's disease) is reduced by alcohol and certain polyphenols in wine.
Obesity
At present, certain groups are warning people about the excess calories that drinking wine or other alcoholic beverages can add to one's diet. Does wine contain calories? Yes, between 100 to 150 calories for a 4-5 ounce glass of table wine. But is has long been observed in epidemiologic studies that moderate drinkers tend to be leaner, not fatter, than nondrinkers. For a while we thought this was because drinkers were more likely to be smokers who tend to be leaner than nonsmokers, but even when we limit our studies to nonsmokers, we see the same trend.
Scientists are beginning to look at this. One recent intervention study gave men 9 ounces of red wine daily for six weeks, then had them abstain for another six weeks. Adding the wine had no significant effects in terms of body weight.
Other studies have conflicting results as to the extent to which alcohol intake contributes to obesity. But some studies are showing that the calories from wine or alcohol are less likely than calories from other foods to increase weight. This may relate to beneficial effects of alcohol or wine polyphenols on insulin sensitivity, to different pathways of metabolism that are less efficient in utilizing the calories from alcohol, to a reduction of other food intake, or to other mechanisms - we just don't know. Stay tuned, as considerable research on the effects of wine on obesity is being carried out and may provide more good news to wine drinkers in the near future.
Cancer
It has long been known that alcoholics are prone not only to liver cirrhosis but to certain cancers, especially those of the mouth, pharynx, larynx and esophagus. Moderate drinkers are not at increased risk of these diseases, but there may be an exception for breast cancer in women.
Many studies have shown that the risk of breast cancer is slightly increased by even modest alcohol consumption, while others have failed to show any real increase in risk for any except very heavy drinkers. In a large study from Sweden, Mattisson and coworkers found that while high intake of alcohol increased breast cancer risk slightly, there was no increase among consumers of up to 2 drinks per day. In the United States, our own report from more than 5,000 women followed over many decades in the Framingham study did not show an increase in risk with alcohol consumption.
It should be remembered that the degree of protection against cardiovascular diseases from moderate alcohol consumption is much greater than the increase in risk of breast cancer, and cardiovascular diseases in women are about 10 times more common than breast cancer. So the net effects on health and longevity remain positive for women who drink moderately. My own current interpretation of the data relating alcohol to breast cancer is that there may be a slight increase in risk of breast cancer from even moderate alcohol intake for some women, probably related to an increase in estrogen secretion. I hope that within the next few years we will have a better idea of who these women are so that we can advise them appropriately. We should also have additional data soon on a possible protective effect of the polyphenols in wine against various forms of cancer. Such protection is being shown in many animal studies and in a few human studies.
Longevity
One of the largest US follow-up studies was reported by Thun and his colleagues from an American Cancer Society project involving more than 500,000 people between the ages of 35 and 69. In that study, during a follow-up period of up to nine years, the risk of dying of any cause was greatest among abstainers and people reporting 6 or more drinks a day. The lowest risk for total mortality, a 21 percent reduction, was among individuals reporting that they consumed between one-half and 2 drinks per day.
What does a 21 percent or so lower death rate mean in terms of a longer life? Coates and Colleagues reported a 3 to 4 percent increased lifespan for white male drinkers in comparison with abstainers. On average, that translates to only a couple of additional years. What this figure really means, however, is that perhaps 20 percent of the population might avoid death from a heart attack at age 55 and live 10 to 15 years longer.
Drink Wisely, Live Well
A huge number of scientific studies have been done over the past decade, and many more are still under way, on the relationship between wine and health. Every day, scientists identify new mechanisms by which moderate drinking protects against many of the chronic diseases of aging, especially the cardiovascular diseases, which are the leading causes of death throughout the developed world.
Of course, there are certain people who should not drink at all, including individuals who have a history of alcohol or drug abuse and people with selected medical conditions. There are also individuals who have ethical or religious prohibitions against alcohol. So there cannot be a general recommendation for everybody to drink. Every lifestyle decision is a choice in a complex web of factors that varies for each individual. There are many paths to good health.
Just as no one is advising everyone to consume alcohol, I believe that it is unethical for the government or the medical profession to exaggerate the dangers of moderate drinking or to withhold from the public sound and balanced information on alcohol and health. Accurate and balanced data need to be presented to all. And the message from scientists is now very clear: for most individuals in western societies, moderate drinking can be an important and enjoyable component of a healthy lifestyle. But this is an old story. I think that Thomas Jefferson probably described the healthiest lifestyle best more than 150 years ago when he wrote, "I have lived temperately, eating little animal food, and that not as an aliment, so much as a condiment for the vegetables, which constitute my principal diet. I double however, the doctor's glass and a half of wine, and even treble it with a friend."
What will I be doing in coming years to try and stay healthy? I will keep trying to hold my weight under control, eat a reasonable diet and exercise whenever I can, and not smoke. I will also make sure that I have a few glasses of wine with dinner every evening. The type of wine I drink will not be one that someone has recommended because it is high in polyphenols or because it has some other potential health advantage, but the one that I enjoy most with the food I am eating.
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