This is the Amount of Alcohol That Increases Breast Cancer Risk

Updated: May 06, 2021

When it comes to breast cancer prevention, drinking less alcohol and exercising more may help.

Milleflore Images/Shutterstock, frantic00/ShutterstockAlcohol has long been linked to a higher risk of breast cancer, but how much is enough to make a difference? It seems even a moderate intake—drinking one glass of wine, beer, or any other type of alcohol a day—may raise your risk of breast cancer, according to the American Institute for Cancer Research (AICR) and the World Cancer Research Fund.

Based on a 2017 review of 119 studies involving 12 million women from around the globe, the authors found that for every 10 grams of alcohol—that’s 3.3 ounces, less than a typical juice glass—breast cancer risk increased 5 percent for pre-menopausal women and 9 percent for post-menopausal women. Compare that amount to a standard drink, which contains 14 grams of alcohol, according to the National Institute on Alcohol Abuse and Alcoholism.

Alcohol consumption increases levels of estrogen and other hormones that are linked to breast cancer. It can also damage DNA in cells, which increases risk for breast cancer, according to breastcancer.org.

On the plus side, the researchers did uncover a handful of lifestyle tweaks that can help counteract the heightened risk. Most notably, vigorous exercise like running and bicycling may reduce your breast cancer risk. Weight loss may also preventative: Women who are overweight or obese are at a higher risk of post-menopausal breast cancer as are women who gain more weight during g their adult years. These 50 everyday habits may also reduce your risk of breast cancer.

There’s some evidence that other lifestyle choices may help further reduce breast cancer risk; they include breastfeeding, eating dairy, limiting meat, and diets rich in calcium and foods that contain carotenoids (carrots, yams, watermelon, mangoes, etc.) These 10 foods can also lower your risk for breast cancer.

Anne McTiernan, MD, PhD, one of the report’s lead authors and a cancer prevention researcher at the Fred Hutchinson Cancer Research Center in Seattle, notes that while being physically active, keeping a healthy weight, and reducing alcohol intake will help you lower your breast cancer risk, you can’t control your genes, and you may still get diagnosed with breast cancer even if you run marathons and eat buckets of spinach and kale.

Ultimately, no level of alcohol use is safe when it comes to breast cancer, but if you’re going to drink, less is still better than more, Dr. McTiernan says.

Based on their conclusions, the AICR states that 1 in 3 cases could be prevented if women did not drink alcohol, were physically active, and maintained a healthy weight. That’s nearly 83,400 cases of breast cancer each year.