Breastfeeding Prevents Diabetes in Mothers

Randall Neustaedter OMD

This study examined the association of type 2 (adult onset) diabetes in women with their history of lactation. The researchers reviewed the health reports of 240,000 women enrolled in the Nurses' Health Study since 1976. These women initially reported their health status and health-related habits in a detailed questionnaire, and then completed follow-up questionnaires every two years. Of the initial cohorts enrolled in 1976 and 1989, 150,000 women who had children reported their lifetime duration of breastfeeding. Approximately 75 percent of the entire group reported ever breastfeeding their babies.

Results of the study showed that breastfeeding had a protective effect on the later development of diabetes in these women. This study found that each year that a mother breastfed reduced her risk of developing type 2 diabetes by 15 percent. This effect was independent of other risk factors for diabetes including body mass index, diet, exercise, and smoking. The most interesting and convincing finding in this study was the reduced risk of acquiring diabetes attributed to the length and intensity of breastfeeding. Each year of exclusive breastfeeding was associated with a greater diabetes risk reduction than a similar duration of breastfeeding if babies received supplementary formula as well. Similarly, a longer duration of breastfeeding per pregnancy was associated with a greater benefit. One year of lactation with one child resulted in a 44 percent reduction in risk compared with a 24 percent reduction in risk for a woman who breastfed different children for a total of one year.

These results point to a remarkable health benefit for women as a result of breastfeeding. And they show that the longer a woman breastfeeds her child, and the longer the time she exclusively breastfeeds, the greater the benefit to her health. We know the tremendous advantages of breastfeeding for infants, including benefits on both health and intelligence that extend far into the child's future, even as an adult. This study contributes further evidence that breastfeeding also confers protection for mothers from serious, life-threatening disease. Previous studies have associated duration of breastfeeding with a reduced risk of breast cancer and ovarian cancer. The message from these studies should encourage all women to breastfeed as long as practicable, and should convince medical providers to encourage exclusive breastfeeding for the first six months of life and extended breastfeeding whenever possible.

Stuebe AM, et al. Duration of lactation and incidence of type 2 diabetes. JAMA, Journal of the American Medical Association. 2005, Nov 23; 294 (20):2601-2610.