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: In an exhaustive new report, 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. 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.
- Alcohol plays a role in one in three cases of violent crime.
- More than 16,000 people die each year in automobile accidents in which alcohol is involved.
- Alcohol abuse costs more than $185 billion dollars a year.
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.
Alcohol Increases Risk of Developing Breast Cancer
There is convincing evidence that alcohol consumption increases the risk of breast cancer. In a combined analysis of six large prospective studies involving more than 320,000 women, researchers found that having two or more drinks a day increased the chances of developing breast cancer as much as 41 percent.
This doesn't mean that 40 percent or so of women who have two drinks a day will get breast cancer. Instead, it is the difference between about 12.7 of every 100 women developing breast cancer during their lifetime—the current average risk in the US—and 17 to 18 of every 100 women developing the disease. This modest increase would translate to significantly more women with breast cancer each year.
Adequate daily intake of folate, at least 600 micrograms a day, appears to mitigate this increased risk.
Genes Play a Role
Twin, family, and adoption studies have firmly established that genetics plays an important role in determining an individual's preferences for alcohol and his or her likelihood for developing alcoholism. Alcoholism doesn't follow the simple rules of inheritance set out by Gregor Mendel. Instead, it is influenced by several genes that interact with each other and with environmental factors.
There is also some evidence that genes influence how alcohol affects the cardiovascular system. An enzyme called alcohol dehydrogenase helps metabolize alcohol. One variant of this enzyme, called alcohol dehydrogenase type 1C (ADH1C), comes in two "flavors." One quickly breaks down alcohol, the other does it more slowly. Moderate drinkers who have two copies of the gene for the slow-acting enzyme are at much lower risk for cardiovascular disease than moderate drinkers who have two genes for the fast-acting enzyme.Those with one gene for the slow-acting enzyme and one for the faster enzyme fall in between.
It's possible that the fast-acting enzyme breaks down alcohol before it can have a beneficial effect on HDL and clotting factors. Interestingly, these differences in the ADH1C gene do not influence the risk of heart disease among people who don't drink alcohol. This adds strong indirect evidence that alcohol itself reduces heart disease risk.
Shifting Benefits and Risks
The benefits and risks of moderate drinking change over a lifetime. In general, risks exceed benefits until middle age, when cardiovascular disease begins to account for an increasingly large share of the burden of disease and death.
- For a pregnant woman and her unborn child, a recovering alcoholic, a person with liver disease, and people taking one or more medications that interact with alcohol, moderate drinking offers little benefit and substantial risks.
- For a 30-year-old man, the increased risk of alcohol-related accidents outweighs the possible heart-related benefits of moderate alcohol consumption.
- For a 60-year-old man, a drink a day may offer protection against heart disease that is likely to outweigh potential harm (assuming he isn't prone to alcoholism).
- For a 60-year-old woman, the benefit/risk calculations are trickier. Ten times more women die each year from heart disease (460,000) than from breast cancer (41,000). However, studies show that women are far more afraid of developing breast cancer than heart disease, something that must be factored into the equation.
