Is there a link between alcohol and breast cancer?

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Can as little as one alcoholic drink a day raise your breast cancer risk? Studies say yes. But does that mean you should steer clear of alcohol completely? And what about that glass of wine that’s supposed to be good for you?

More than 100 studies have looked at the association between alcohol consumption and breast cancer risk in women. Although observational, these studies draw on inferences from researchers and have consistently found an increased risk of breast cancer associated with alcohol intake.

The risk is low, but there does seem to be a connection. Therese Bevers, medical director of MD Anderson’s Cancer Prevention Center, says, “You need to be concerned if it becomes a routine in which you drink more than one drink each day. We always question the validity of observational data but, with this, we see it over and over again,” Bevers says.

Alcoholic drinks come in three choices: beer, wine and liquor. A drink is defined as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of liquor. If you choose to drink, exceeding the recommended limit of one alcoholic drink a day increases your breast cancer risk. While some studies show that one daily glass of red wine may be good for your heart, you shouldn’t have more than that. 

How does alcohol affect breast cancer risk?

Alcohol consumption may lead to breast cancer because alcohol can increase levels of estrogen and other hormones associated with breast cancer. Alcohol users are more likely to have increased amounts of folic acid in their systems, leading to increased cancer risk. Alcoholic beverages may also contain various carcinogenic contaminants introduced during fermentation and production, such as nitrosamines, asbestos fibers, phenols and hydrocarbons. Alcohol is empty calories and can lead to unwanted weight gain; excess fat can lead to increased cancer risk.

Alcohol also may increase breast cancer risk by damaging DNA in cells. Compared to women who don’t drink at all, women who have three alcoholic drinks per week have a 15 percent higher risk of breast cancer. Experts estimate that breast cancer risks go up another 10 percent for each additional drink women regularly have each day.

There is a strong scientific consensus that alcohol drinking can cause several types of cancer. In its Report on Carcinogens, the National Toxicology Program of the US Department of Health and Human Services lists alcoholic beverages as a known human carcinogen.

The evidence indicates that the more alcohol a person drinks—particularly the more alcohol a person drinks regularly over time—the higher their risk of developing alcohol-associated cancer. Even those who have no more than one drink per day and binge drinkers (those who consume four or more drinks for women and five or more drinks for men in one sitting) have a modestly increased risk of some cancers. Based on data from 2009, an estimated 3.5 percent of cancer deaths in the United States (about 19,500 deaths) were alcohol-related.

What to do

To cut back on your alcohol consumption and lower your breast cancer risk, follow these guidelines:

Select low-calorie options to avoid unwanted weight gain.

Stay away from 100-proof liquor. Researchers believe that the ethanol or alcohol in beer, wine and liquor causes increased cancer risk.

Avoid alcohol as often as possible.

According to the federal government’s Dietary Guidelines for Americans, 2020–2025, individuals who do not drink alcohol should not start drinking. The Dietary Guidelines also recommend that people who drink alcohol do so in moderation by limiting consumption to two drinks or less in a day for men and one drink or less in a day for women. Heavy alcohol drinking is defined as having four or more drinks on any day or eight or more drinks per week for women and five or more drinks on any day or 15 or more drinks per week for men.