People who drink in moderation are different from non-drinkers or heavy drinkers in ways that could influence health and disease.
Folate, the B vitamin that helps guide the development of an embryo’s spinal cord, has equally important jobs later in life. One of the biggest is helping to build DNA, the molecule that carries the code of life. In this way, folate is essential for accurate cell division.
Alcohol blocks the absorption of folate and inactivates folate in the blood and tissues. It’s possible that this interaction may be how alcohol consumption increases the risk of breast, colon, and other cancers.
Getting extra folate may cancel out this alcohol-related increase. In the Nurses’ Health Study, for example, among women who consumed one alcoholic drink a day or more, those who had the highest levels of this B vitamin in their blood were 90% less likely to develop breast cancer than those who had the lowest levels of the B vitamin. (28) An earlier study suggested that getting 600 micrograms a day of folate could counteract the effect of moderate alcohol consumption on breast cancer risk. (26)
Part of a national 1985 health interview survey showed that moderate drinkers were more likely than non-drinkers or heavy drinkers to be at a healthy weight, to get seven to eight hours of sleep a night, and to exercise regularly. (11) Researchers have statistically accounted for such confounders, and they do not come close to accounting for the relationship between alcohol and heart disease. This, plus the clearly beneficial effects of alcohol on cardiovascular risk factors, makes a compelling case that alcohol itself, when used in moderation, reduces the risk of cardiovascular disease.
The most definitive way to investigate the effect of alcohol on cardiovascular disease would be with a large trial in which some volunteers were randomly assigned to have one or more alcoholic drinks a day and others had drinks that looked, tasted, and smelled like alcohol but were actually alcohol free. Many of these trials have been conducted for weeks, and in a few cases months, to look at changes in the blood, but a long-term trial to test experimentally the effects of alcohol on cardiovascular disease over many years will probably never be done. Nevertheless, the connection between moderate drinking and cardiovascular disease almost certainly represents a cause-and-effect relationship.
Beyond the Heart
The benefits of moderate drinking aren’t limited to the heart. In the Nurses’ Health Study, the Health Professionals Follow-up Study, and other studies, gallstones (12, 13) and type 2 diabetes (5, 14, 15) were less likely to occur in moderate drinkers than in non-drinkers. The emphasis here, as elsewhere, is on moderate drinking. In a meta-analysis of 15 original prospective cohort studies that followed 369,862 participants for an average of 12 years, no benefit was observed for heavy drinkers who consumed more than 48 grams of alcohol (the equivalent of four drinks) a day. (5) The social and psychological benefits of alcohol can’t be ignored. A drink before a meal can improve digestion or offer a soothing respite at the end of a stressful day; the occasional drink with friends can be a social tonic. These physical and psychic effects may contribute to health and well-being.
Drinking Patterns Matter
What you drink (beer or wine) doesn’t seem to be nearly as important as how you drink. Having seven drinks on a Saturday night and then not drinking the rest of the week isn’t at all the equivalent of having one drink a day. The weekly total may be the same, but the health implications aren’t. Among participants in the Health Professionals Follow-up Study, consumption of alcohol on at least three or four days a week was inversely associated with the risk for myocardial infarction. The amount consumed, under 10 grams a day or more than 30 grams, didn’t seem to matter as much as the regularity of consumption. (16) A similar pattern was seen in Danish men. (17)
If all drinkers limited themselves to a single drink a day, we probably wouldn’t need as many cardiologists, liver specialists, mental health professionals, and substance abuse counselors. But not everyone who likes to drink alcohol stops at just one. While most people drink in moderation, some don’t.
On the personal level, heavy drinking can take a toll on the body. It can cause inflammation of the liver (alcoholic hepatitis) and lead to scarring of the liver (cirrhosis), a potentially fatal disease. Heavy drinking can increase blood pressure and damage heart muscle (cardiomyopathy). It has also been linked with several cancers: The World Cancer Research Fund and American Institute for Cancer Research indicate that there is convincing evidence linking alcohol use to cancer of the mouth, pharynx, larynx, esophagus, breast, and colon and rectum in men, and probable evidence that its use contributes to liver cancer and colorectal cancer in women. (18) The risk is multiplied for drinkers who also smoke tobacco.
Problem drinking also touches drinkers’ families, friends, and communities. According to the National Institute on Alcohol Abuse and Alcoholism and others:
- 18.2 million Americans meet standard criteria for alcohol abuse or alcoholism. (19)
- Alcohol plays a role in one in three cases of violent crime. (20)
- More than 16,000 people die each year in automobile accidents in which alcohol is involved. (21)
- Alcohol abuse costs more than $185 billion dollars a year. (22)
Even moderate drinking carries some risks. Alcohol can disrupt sleep. Its ability to cloud judgment is legendary. Alcohol interacts in potentially dangerous ways with a variety of medications, including acetaminophen, antidepressants, anticonvulsants, painkillers, and sedatives. It is also addictive, especially for people with a family history of alcoholism.