Does Breast-Feeding Really Decrease Breast Cancer Risk?

For babies, the benefits of breast-feeding are clear: a stronger immune system, reduced risk for some chronic health conditions and a closer bond with mom. But does breast-feeding also protect women against breast cancer?

Nursing has been linked to a reduced risk of breast cancer in both pre- and post-menopausal women. But, says Virginia Borges, director of the University of Colorado Cancer Center's young women's breast cancer program, "it gets complicated from here."

Nursing a baby changes the structure of the breast. Even after breast-feeding ends, microscopic changes in the milk-delivery system protect the breast against precancerous cells, Borges says. This effect is more common among women who have nursed more children or for longer periods than others.

The older a woman is when she gives birth for the first time, the more likely she is to get breast cancer. But, Borges says, it's not that simple. "I would never want a woman to decide to not have a child because of anything related to breast cancer."

Breast-feeding may moderately offset the increased risk of breast cancer associated with pregnancy: Research has shown that women who breast-feed can cut their risk of some aggressive breast cancers by up to 20 percent relative to women who don't nurse.

One group of women, though, doesn't seem to experience the same effects: African Americans. Although white women experience breast cancer more often after menopause than African American women do, young African American women are more likely than white women to face aggressive, early-onset forms of breast cancer.

Black women also breast-feed less often. According to the Centers for Disease Control and Prevention, substantially fewer African American babies than white babies are breast-fed. Breast-feeding a baby has been found to be protective against both short-term and longer-term health issues for mother and child. Black women are more likely than others to face lack of support for breast-feeding at work, may lack community support and may have cultural attitudes that influence them not to nurse. Hospitals play a role, too: In 2014, the CDC reported that hospitals with a larger population of African American patients were less likely than others to promote breast-feeding.

So should you plan on nursing to potentially stave off breast cancer? Absolutely, Borges says, but "it takes two to tango." Not every woman or baby can successfully nurse, and breast-feeding may not be an option because of cultural, lifestyle and other factors.

If a woman isn't able to breast-feed or chooses not to, lifestyle choices could help stave off breast cancer even without the protective effect of nursing. Things such as moderating or eliminating alcohol and exercising are strongly linked to protection against pre-menopausal breast cancers. And, Borges says, there's no reason to think they can't help protect against breast cancers in younger women, too.

Special to The Washington Post