TUESDAY, Nov. 22 (HealthDay News) -- Breast-feeding your baby can cut your risk of developing type 2 diabetes, new research shows.
"We found that breast-feeding is really good for mothers. Each year she breast-feeds cuts the risk of type 2 diabetes by 15 percent," said study author, Dr. Alison Stuebe, a clinical fellow in maternal fetal medicine at Brigham and Women's Hospital, and an instructor at Harvard Medical School in Boston.
Breast-feeding offers a host of health benefits for babies. Along with providing optimal nutrition, breast milk also provides compounds that boost babies' immune system and help protect against bacteria, viruses and parasites, according to the U.S. Food and Drug Administration. In addition, breast-fed children have lower rates of childhood illnesses and tend to be leaner than their formula-fed counterparts.
And research has shown mothers benefit as well: Breast-feeding helps a mother's body return to normal faster after pregnancy, according to the FDA. Some studies have suggested that women who breast-feed for long periods of time may have lower rates of breast and ovarian cancer.
But, no long-term studies had examined the effect of breast-feeding on maternal risk of diabetes, Stuebe said.
Stuebe and her colleagues suspected breast-feeding might affect type 2 diabetes risk because it substantially changes a mother's metabolic requirements, and research has shown that breast-feeding improves insulin sensitivity and glucose tolerance.
The researchers used data from the Nurses' Health Study and the Nurses' Health Study II, which together included more than 150,000 women who had given birth during the study period. More than 6,000 of these women were diagnosed with type 2 diabetes.
After controlling for body mass index (BMI) -- because a high BMI is a known risk factor for type 2 diabetes -- the researchers found that long-term breast-feeding reduced a woman's risk of developing diabetes.
The risk was decreased by 15 percent for each year of breast-feeding for women in the Nurses' Health Study, and by 14 percent for each year for those in the Nurses' Health Study II, according to the findings, which are published in the Nov. 23/30 issue of the Journal of the American Medical Association.
Stuebe said the researchers weren't able to determine how breast-feeding might offer some protection against diabetes, only that breast-feeding was associated with a drop in the rate of type 2 diabetes.
However, she said, the researchers suspect that breast-feeding may help keep blood sugar in balance, or "homeostasis."
Breast-feeding mothers burn almost 500 additional calories daily, according to the study. That's equivalent to running about four to five miles a day, Stuebe noted.
"If done for a year, it's not surprising that it might have an effect on how the body takes care of insulin and glucose," she said.
Dr. Loren Wissner Greene, an endocrinologist at New York University Medical Center in New York City, said the explanation for why women who breast-feed for long periods may have lower rates of diabetes could be a simple one: "The small weight changes from lactation can make a significant impact on diabetes risk."
In fact, Wissner Greene said, the best advice for anyone to avoid type 2 diabetes is to maintain a healthy weight, and lose weight if you're carrying excess weight.
Another potential explanation could be that women who breast-feed for a long time are more health-conscious than other women, and may have a healthier diet, may exercise more and do other health-promoting activities that could reduce their diabetes risk.
Stuebe said the researchers tried to take lifestyle factors into account and still saw an association between breast-feeding and reduced diabetes risk.
The bottom line, said Stuebe: "We're talking about an intervention that doesn't cost anything, has no side effects and has other potential benefits."
You can find out more about the benefits of breast-feeding for both mom and baby from The National Women's Health Information Center.