Consuming one glass of wine or other alcoholic beverage per day may increase a woman’s risk for breast cancer, according to a study from the American Institute for Cancer Research (AICR) and the World Cancer Research Fund (WCRF).

Investigators also found that vigorous exercise such as running or fast bicycling decreases the risk of premenopausal and post-menopausal breast cancer, and moderate exercise decreases the risk of post-menopausal breast cancer.

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“With this comprehensive and up-to-date report, the evidence is clear,” stated Anne McTiernan, MD, PhD, from the Fred Hutchinson Cancer Research Center in Seattle and a lead author of the study. “Having a physically active lifestyle, maintaining a healthy weight throughout life, and limiting alcohol are all steps women can take to lower their risk.”

The researchers analyzed 119 studies, which included 12 million women and 260,000 cases of breast cancer. Dr McTiernan’s group found that drinking the equivalent of a small glass of wine or beer a day (about 10 grams of alcohol) increases pre-menopausal breast cancer risk by 5% and post-menopausal breast cancer risk by 9%.

Pre-menopausal women who are the most active regarding vigorous exercise have a 17% lower risk and post-menopausal women have a 10% lower risk of developing breast cancer compared with women who are the least active. Total moderate activity, such as walking and gardening, is associated with a 13% lower risk, when comparing the most active women with the least active women.

The investigators also found that:

  • Being overweight or obese increases the risk of post-menopausal breast cancer.
  • Mothers who breastfeed have a lower risk for breast cancer.
  • Greater adult weight gain increases the risk of post-menopausal breast cancer.

The AICR estimates that 1 in 3 breast cancer cases in the US could be prevented if women did not drink alcohol, were physically active, and maintained a healthy weight.

The study also found limited evidence that non-starchy vegetables lower the risk for estrogen-receptor (ER) negative breast cancers. Limited evidence also shows that dairy products, diets high in calcium, and foods containing carotenoids are associated with lowering the risk of some types of breast cancer.

“The findings indicate that women may get some benefit from including more non-starchy vegetables with high variety, including foods that contain carotenoids,” stated Dr McTiernan. “That can also help avoid the common 1 to 2 pounds women are gaining every year, which is key for lowering cancer risk.”

The report is part of the Continuous Update Project (CUP), an ongoing analysis of the global research on how diet, nutrition, physical activity, and weight affect cancer risk and survival.


  1. New report: Just one alcoholic drink a day increases breast cancer risk, exercise lowers risk [news release]. American Institute for Cancer Research. May 23, 2017.