News article

Breastfeeding Cuts Maternal Diabetes Risk

November 23, 2005

(Boston) Moms who breastfeed may be protected from type 2 diabetes, according to a new study from Boston’s Brigham and Women’s Hospital, published today in the Journal of the American Medical Association. Researchers demonstrated that breastfeeding a child for one year may reduce a woman’s risk of developing Type 2 diabetes by 15 percent.

“We’ve known for a long time that breastfeeding is good for babies,” said lead author and BWH researcher, Alison Stuebe, MD. “In this study, we found that it’s good for moms too.” Dr. Stuebe is also on the Massachusetts Breastfeeding Coalition’s Board of Directors.

The production of milk requires a breastfeeding mother to use an average of 500 calories each day-the equivalent of running four to five miles. According to Stuebe, the additional energy required for lactation is associated with short-term changes in insulin, and glucose. Her study was among the first to look at the long-term association between breastfeeding and incidence of Type 2 diabetes. “Our study supports the theory that breastfeeding may be associated with important metabolic changes that influence diabetes risk,” she said. “However more research is needed to determine what hormonal and biological factors are involved.” The researchers found that women who breastfed for at least one year were less likely to develop Type 2 diabetes than woman who did not breastfeed. Specifically, they report:

• One year of breastfeeding was associated with a 15 percent drop in a woman’s risk of developing Type 2 diabetes. This protective effect appeared to last up to 15 years after a woman’s last birth.
• Each additional year of breastfeeding was associated with a greater reduction in risk. For example, according to Stuebe, if a woman had two children and breastfed each child for a year, the data suggest that the mother may reduce her risk of diabetes by a third.
• Women with gestational diabetes did not appear to lower their risk of Type 2 diabetes, even if they breastfed intensely.
• In addition, the data suggest that women who used medications to prevent lactation had an increased risk for Type 2 diabetes.

“Based on these findings, we have one more reason to encourage mothers to breastfeed,” Stuebe said. “Ensuring strong support for nursing mothers – from doctors and nurses to family members and employers – isn’t just important for babies. It’s a women’s health issue, too.”

The study included more than 157,000 nurses who were enrolled in the Nurses’ Health Studies, two cohorts of women who ranged from age 26 to 71 at the start of the study. The nurses responded to questionnaires regarding how many children they breastfed and for how long, as well as numerous questions about their health, including whether or not they had been diagnosed with Type 2 diabetes by a physician. The researchers controlled for multiple factors including diet, exercise, weight, and multivitamin use.