There's ample evidence that breast-feeding is good for a child's health. Now, a study appearing in this week's Journal of the American Medical Association suggests that it's not just Baby that benefits: Nursing seems to lower a mother's risk of diabetes. "This is another reason women should really think about giving it a shot," says lead researcher Alison Stuebe, an obstetrician and gynecologist at Brigham and Women's Hospital in Boston.

The study of more than 157,000 mothers found that for each year a woman breast-fed her baby, she was 15 percent less likely to develop type 2 diabetes in the next 15 years. It didn't matter how a woman tallied up the time; feeding one baby for 12 months or two babies for six months each worked equally well. Breast-feeding can help women lose weight, a key factor in diabetes prevention.

But researchers suspect their results have more to do with the fact that lactation improves the body's ability to process insulin and metabolize blood sugar. (Women who had gestational diabetes, a usually temporary condition during pregnancy, did not reduce their risk by breast-feeding; only losing weight helped them.)

Previous studies have shown that women who nurse their babies have a lower risk of breast and ovarian cancers, hip fracture, and rheumatoid arthritis, according to Judy Hopkinson, a lactation physiologist at Baylor School of Medicine who has researched breast-feeding but was not involved in this study. Still, according to the Centers for Disease Control and Prevention, only about 36 percent of moms are nursing at the six-month mark. Many want to continue longer, says Hopkinson, but short maternity leaves and an intolerance for breast-feeding in public conspire against them.

See our Diabetes Center for more information.