A new study suggests a link between breast-feeding and a lowered risk of heart disease in older women.
The research by Chinese investigators found that women who breast-fed may have lowered their risk of heart disease or stroke by an average of 10 percent when they became older.
Researchers at the Chinese Academy of Medical Sciences, Peking University and the University of Oxford analyzed data on 289,573 women whose average age was 51.
They found that those who breast-fed had a 9 percent lower risk of heart disease and an 8 percent decreased risk of stroke, compared with women who had never nursed. The benefit was even greater for women who breast-fed their babies for two years or more. Their heart disease risk was 18 percent lower and the risk of stroke 17 percent less.
Each additional month of breast-feeding was associated with a 4 percent and 3 percent lower risk of heart disease and stroke, respectively, researchers said.
The findings of the study, the first to look at the long-term health benefits of breast-feeding for women, were published in the Journal of the American Heart Association.
Hormone's possible role
Cardiologist Nieca Goldberg, who was not involved in the study, said the cardiovascular benefits could have been related to the release of oxytocin during breast-feeding.
"Oxytocin is a hormone that helps the flexibility of our blood vessels," she said. "And flexible blood vessels are resistant to the buildup of plaque or cholesterol in the walls of the arteries."
Breast-feeding provides a number of benefits, such as conferring a mother's immune protection to her infant and protecting a newborn from life-threatening infections in countries with poor water quality.
There are short-term benefits for mothers, too. Studies indicate that breast-feeding appears to reset the woman's metabolism after pregnancy, so she loses baby weight faster, while lowering her cholesterol, blood pressure and glucose levels.
Goldberg, medical director at the Joan H. Tisch Center for Women's Health in New York, said it was possible that women in the study who breast-fed, and saw heart healthy benefits, might have also led healthier lifestyles compared with other women.
"For those women who don't choose to breast-feed, there are other things they can do to prevent heart disease," said Goldberg. "And that's certainly by exercising, something as simple as taking a walk and eating a healthy diet, rich in fruits, vegetables, whole grains and low-fat proteins."
Goldberg cautioned that the Chinese study was observational, relying on information provided by the mothers many years after they had given birth, so the findings do not prove a cause-and-effect relationship. She said what's needed is a head-to-head comparison of women who breast-feed with a control group of those who don't, to see whether there are long-term heart-healthy benefits.