The Alcohol-Breast Cancer Connection

Even moderate drinking can increase your breast cancer risk. Learn if your alcohol consumption could be putting your health in danger.

Medically reviewed by Lindsey Marcellin, MD, MP 

You might have read that drinking red wine has certain health benefits, or maybe you just enjoy a cocktail before dinner. But if you take part in this practice nightly, could you be raising your breast cancer risk? A look at the research suggests that the answer is yes, especially if you don’t stop at just one drink.

“There is considerable evidence that alcohol, even at low amounts of consumption, increases the risk of breast cancer in both pre-menopausal and post-menopausal women,” says Susan Gapstur, PhD, MPH, vice president of epidemiology at the American Cancer Society (ACS). That risk goes up with every drink. To guard against many types of cancer, the ACS recommends that women drink no more than one drink a day.

Drinking and Breast Cancer Risk

The link between drinking alcohol and breast cancer risk has been the focus of many studies. One of the most recent and largest, called the “Million Women Study,” suggests that small to moderate amounts of any type of alcohol, including beer, raise the risk of breast and other cancers.

Oxford University researchers tracked cancer risk and alcohol use in more than 1 million middle-aged women. The study participants’ average age was 55 years old, and three-quarters of the group reported they were drinkers. The average amount of alcohol consumed was one drink a day. Very few women reported three or more daily drinks. Over the study’s seven years, almost 69,000 women were diagnosed with cancer. The researchers found that women who drank were at increased risk of several cancers, including breast cancer, and concluded that each additional drink consumed each day was associated with 11 additional breast cancers per 1,000 women up to age 75.

An earlier study by the International Agency for Research on Cancer, an arm of the World Health Organization, found similar data. Researchers analyzed more than 40 epidemiologic studies and found that the equivalent of two drinks a day may boost risk by 21 percent.

To add even more fuel to the fire, a recent analysis of more than 180,000 post-menopausal women in the National Institutes of Health-American Association of Retired Persons Diet and Health study found that women who drank three or more drinks a day had more than a 50 percent increased risk of the most common type of breast cancer. By contrast, women who consumed one to two drinks a day had a 32 percent increased risk. Those that drank less than one drink daily still had a 7 percent increased risk compared to women who did not drink any alcohol.

How Does Drinking Raise Breast Cancer Risk?

That’s the lingering question facing breast cancer researchers studying the connection.

“How alcohol might lead to breast cancer is not completely understood. It might be due to an alcohol-associated increase in circulating estrogen or other hormone levels, or there might be a direct action of the products formed from alcohol in the body on breast tissue,” says Gapstur.

Sorting out exactly how alcohol works to raise risk — and which women could be more susceptible to its negative effects — may help medical experts come up with more personalized recommendations to women about their alcohol use.

To Drink or Not to Drink

At the other end of the spectrum, it’s also believed that light to moderate drinking has potential health benefits. Some large studies have shown that it can lower the risk of heart disease, the leading killer of women in the United States.

So what’s a woman to do? Gapstur says a conversation with your doctor can better flesh out your personal risks and benefits of drinking. If you are at high risk for breast cancer, you probably should strictly limit your alcohol use, she says.

Keep in mind that excessive drinking can lead to many different cancers and other problems, including heart disease, so don’t gamble with your health. Says Gapstur, “While a woman might want to have two glasses of wine, for example, on a special evening, consuming more than one drink per day should not become a regular pattern.”