The Dark Side of Alcohol

The Dark Side of Alcohol

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. Problem drinking affects not just the drinkers themselves, but may touch their families, friends, and communities. According to the National Institute on Alcohol Abuse and Alcoholism: (1)

14 million Americans meet standard criteria for alcohol abuse or alcoholism
Alcohol plays a role in 1 in 4 cases of violent crime
More than 16,000 people die each year in automobile accidents in which alcohol was involved
Alcohol abuse costs more than $180 billion dollars a year
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, particularly those of the mouth, throat, esophagus, colon, and breast.

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

Among women in the Nurses' Health Study, two or more drinks a day increased the chances of developing breast cancer by 20%-25%.(14, 15 ) This doesn't mean that 20% to 25% of women who have two drinks a day will get breast cancer. Instead, it is the difference between about 12 of every 100 women developing breast cancer during their lifetimes - the current average risk in the US - and 14 to 15 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 folic acid, at least 600 micrograms a day, can mitigate this increased risk.

The Vitamin-Alcohol-Cancer Connection

What is the connection between alcohol, folic acid, and breast cancer? Folic acid, the B vitamin that helps guide the development of an embryo's spinal cord has equally important jobs later in life. It helps the body get rid of homocysteine. This byproduct of protein metabolism appears to be involved with the development of atherosclerosis, the gradual accumulation of cholesterol-filled patches in artery walls that often precedes heart attacks and strokes. Folic acid also helps build DNA and so is involved with accurate cell division.

Alcohol blocks the absorption of folic acid and inactivates folic acid 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 folic acid 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.(21) An earlier study suggested that getting 600 micrograms a day of folic acid could counteract the effect of moderate alcohol consumption on breast cancer risk.(22)


Similarly, an excess risk of colon cancer seen with the consumption of more than two drinks per day appears to be largely eliminated by adequate intake of folic acid.(29)

Based on this and other research, women and men who drink alcohol regularly should be sure to get adequate intake of folic acid--at least 600 micrograms a day. This can be obtained through a healthy diet that is rich in fruits, vegetables, dry beans, and whole grains. Taking a multivitamin supplement (most contain 400 micrograms of folic acid) is also a good idea as a nutritional safety net.


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.(1)

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.(16) Those with one gene for the slow-acting enzyme and one for the faster enzyme fell 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 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 potential 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. More than ten times as many women die each year from heart disease than breast cancer - more than 500,000 women a year from cardiovascular disease compared with 41,000 a year from breast cancer. However, studies show that women are far more afraid of developing breast cancer than heart disease, something that must be factored into the equation.
Balancing Act

Given the complexity of alcohol's effects on the body and the complexity of the people who drink it, blanket recommendations about alcohol are out of the question. Because each of us has unique personal and family histories, alcohol offers each person a different spectrum of benefits and risks. Whether or not to drink alcohol, especially for "medicinal purposes," requires careful balancing of these benefits and risks. Your health-care provider should be able to help you do this.

Your overall health and risks for alcohol-associated conditions should factor into the equation. If you are thin, physically active, don't smoke, eat a healthy diet, and have no family history of heart disease, drinking alcohol won't add much to decreasing your risk of CVD.

If you don't drink, there's no need to start. You can get similar benefits with exercise (beginning to exercise if you don't already or boosting the intensity and duration of your activity) or healthier eating. If you are a man with no history of alcoholism who is at moderate to high risk for heart disease, a daily alcoholic drink could reduce that risk. Moderate drinking might be especially beneficial if you have low HDL that just won't budge upward with diet and exercise. If you are a woman with no history of alcoholism who is at moderate to high risk for heart disease, the possible benefits of a daily drink must be balanced against the small increase in risk of breast cancer.

If you already drink alcohol or plan to begin, keep it moderate - no more than two drinks a day for men or one drink a day for women. And make sure you get plenty of folic acid, at least 600 micrograms a day.

Participants Duration Association with moderate consumption*
Kaiser Permanente cohort: 123,840 men and women aged 30+ 10 years 40% reduction in fatal myocardial infarction, 20% reduction in cardiovascular mortality; 80% increase in fatal hemorrhagic stroke (23)
Nurses' Health Study: 85,709 female nurses aged 34-59 12 years 17% lower risk of all-cause mortality; (24) an earlier report showed a 40% reduction in risk of CHD and 70% reduction in risk of ischemic stroke (25)
Physicians' Health Study: 22,071 male physicians aged 40-84 11 years 30-35% reduced risk of angina and myocardial infarction, 20-30% reduced risk of cardiovascular death (7, 26 )
American Cancer Society cohort: 489,626 men and women aged 30-104 9 years 30-40% reduced risk of cardiovascular death (27)
Eastern France cohort: 34,014 men and women 10-15 years 25-30% reduced risk of cardiovascular death (28)
Health Professionals Follow-up Study: 38,077 male health professionals aged 40-75 12 years 35% reduced risk of myocardial infarction (20)

* compared with non-drinkers


Table 1. Results of some large prospective studies of alcohol consumption and cardiovascular disease