A report from the American Institute for Cancer Research and the World Cancer Research Fund bolsters what earlier research has strongly suggested: just one small glass of wine or other alcoholic beverage per day increases breast cancer risk.
The report also strongly suggests that vigorous exercise, such as running or other high intensity cardio, decreases the risk of breast cancer.
The report was published online on May 23, 2017. Read “Continuous Update Project Report: Diet, nutrition, physical activity and breast cancer.”
Breastcancer.org Professional Advisory Board member Anne McTiernan, M.D., Ph.D., director of the Cancer Prevention Center at the Fred Hutchinson Cancer Research Center, is one of the report’s lead authors.
Sipping an average of 10 grams of alcohol a day -- which is equal to a small glass of wine, 8 ounces of beer (a can of beer is 12 ounces), or 1 ounce of hard liquor -- is linked to a 5% increase in breast cancer risk in premenopausal women and 9% increase in postmenopausal women, said McTiernan.
"I was most surprised by the alcohol result, that risk increases at just one drink a day, on average," McTiernan said. "The increase with one drink a day was small, but the risk goes up from there. This suggests there is no level of alcohol use that is completely safe in terms of breast cancer."
To develop the report, the researchers analyzed 119 studies done worldwide on how diet, weight, and exercise affect breast cancer risk. The studies included more than 12 million women.
The report also showed that:
- Premenopausal women who did the most vigorous exercise had a 17% lower risk of breast cancer and postmenopausal women had a 10% lower risk compared to women who were the least active.
- Women who did the most moderate activity, such as walking or gardening, had a 13% lower risk of breast cancer compared to women who were the least active.
- Being overweight or obese increases the risk of postmenopausal breast cancer.
- Women who breastfeed have a lower risk of breast cancer.
- Gaining more weight as an adult increases the risk of postmenopausal breast cancer.
Every woman wants to know what she can do to lower her risk of breast cancer. Some of the factors associated with breast cancer -- being a woman, your age, and your genetics, for example -- can’t be changed. Other factors -- being overweight, lack of exercise, eating unhealthy food -- can be changed by making choices. By choosing the healthiest lifestyle options possible, you can empower yourself and make sure your breast cancer risk is as low as possible.
Experts recommend the following strategies to keep your risk of breast cancer as low as it can be:
- Eat a diet full of vegetables, fruits, and whole grains and avoid foods with added sugar and processed foods.
- Exercise regularly at a moderate or vigorous level.
- Avoid gaining weight as you age.
- If you have gained weight as you’ve aged, lose about 10% of your body weight (and keep it off) after menopause.
- Avoid or limit alcohol.
- Avoid using medicines such as hormone replacement therapy that contains estrogen and progesterone.
- Women at high risk for breast cancer because of family history or an abnormal gene should consider taking preventive medicine such as tamoxifen or Evista (chemical name: raloxifene).
You can learn much more about breast cancer risk and other steps you can take to minimize your risk in the Breastcancer.org Lower Your Risk pages.