Alcohol: a heart disease-cancer balancing act

The message that drinking a little alcohol is good for the heart has gotten plenty of attention. A new study linking alcohol with increased risk of dying from various cancers may temper that message a bit.

About 4% of cancer deaths worldwide are related to alcohol use. No one has done a major study of this issue in the United States for more than 30 years. During that time, we’ve learned a lot about alcohol and cancer, and powerful statistical methods have been developed for estimating risk.

Researchers from the National Cancer Institute and other institutions delved into many studies and information databases. They calculated that alcohol causes 3.5% of U.S. cancer deaths, or about 20,000 cancer-related deaths each year. The study was published online yesterday in the American Journal of Public Health.

The most common alcohol-related cancers were mouth, throat, and esophageal cancer in men, and breast cancer in women.

Experts still aren’t completely sure how alcohol causes cancer. Possibilities include:

• toxic effects from chemicals produced when the body breaks down alcohol
• increased production of cell- and DNA-damaging free radicals
• changes in the way the body handles vitamin B₆ (folic acid)
• boosting estrogen levels, which can increase the risk of breast and other cancers
• making other cancer causing agents, such as tobacco products, more harmful

Heart benefits

But what about the reduced risk of heart related deaths in people that drink a little alcohol compared to those that don’t drink at all? A recent detailed analysis of 84 of the best studies looking at the alcohol and heart connection included more than two million men and women. They were followed for an average of 11 years. Compared to people who didn’t drink alcohol, those who were moderate drinkers had a

• 29% lower risk of being diagnosed with coronary artery disease
• 25% lower risk of dying from a heart attack
• 25% lower risk of dying from any heart or blood vessel disease
• 13% lower risk of dying from any cause (this included cancer deaths, too)

Moderate drinking is defined as no more than two alcoholic drinks a day for men and no more than one a day for women.

Striking a balance

The idea that alcohol can be bad and good isn’t a new one. We’ve known for ages that alcohol—usually too much alcohol—can cause liver problems, is a key contributor to automobile accidents and deaths, and can harm personal relationships. The new study adds cancer to alcohol’s potential harms. But moderate alcohol consumption also appears to reduce the odds of developing or dying from heart disease, the leading cause of death in the United States.

If you don’t drink alcohol now, there’s no reason to start. But also don’t worry if you occasionally have a drink.

If you do enjoy alcohol, keep your drinking in the moderate range. You don’t get any additional heart protection by drinking more. And your risk of cancer—and many other problems—rises dramatically with higher consumption.

The issue of whether or not to drink alcohol can be a very tricky one for a woman at higher than average risk of breast cancer or one worried about developing breast cancer. Not drinking would eliminate one possible contributor to breast cancer risk. At the same time, heart disease is more common and deadly among women than breast cancer. An increased heart disease risk might tilt the balance toward moderate alcohol use.

Advances in genetics may one day let us predict more accurately who can use alcohol in moderation and who should avoid it completely. Until then, it’s best to personally weigh the benefits and risks, ideally with a trusted health care provider.