Breast-feeding may offer mothers long-term protection against a condition linked to diabetes and heart disease, researchers report today.
The longer women breast-fed, the lower their chance of developing metabolic syndrome, a cluster of risk factors such as high blood pressure and high triglycerides associated with obesity, the scientists found.
"Pregnancy may have some adverse effects on some of these cardiovascular risk factors," lead author Erica Gunderson says, "and lactation (breast-feeding) may offset some of these effects."
The impact of breast-feeding on the risk of metabolic syndrome was "slightly stronger" in women who'd had gestational — or pregnancy-induced — diabetes, says Gunderson, an epidemiologist and research scientist at Kaiser Permanente's Division of Research in Oakland. "This is the first study to really look at lactation and the metabolic syndrome in women with GDM (gestational diabetes)."
Kavitha T. Ram, a New York Medical College obstetrician/gynecologist, called the study's suggestion that breast-feeding might reverse the metabolic changes associated with gestational diabetes exciting. "There's this emerging evidence that breast-feeding may confer long-term health benefits to the mom," says Ram, who wasn't involved in the study.
About 18%-37% of U.S. women ages 20 to 59 have metabolic syndrome, Gunderson says. A study she published in August found women with gestational diabetes are 2½ times more likely than other women to develop the condition after pregnancy.
Gunderson and her co-authors based their new findings on 704 women in an ongoing, government-funded study of heart-disease risk factors. When the women entered the study in 1985-1986, they were ages 18-30 and had never given birth; testing confirmed they didn't have metabolic syndrome.
They all went on to deliver at least one child; only 16% had more than two children. They returned for measurements of metabolic syndrome components seven, 10, 15 and 20 years after entering the study; 120 developed metabolic syndrome.
In women who didn't have gestational diabetes, breast-feeding cut metabolic syndrome risk 39%-56%. In those who did, it cut the risk 44%-86%. In both, the authors write in Diabetes: The Journal of the American Diabetes Association, the longer women breast-fed, the lower their risk.
Breast-feeding is associated with a quicker loss of pregnancy weight, but that's only "a little bit of the explanation," Gunderson says. Another possibility, she says: Breast-feeding might minimize the accumulation of belly fat, fat linked to type 2 diabetes risk.