Women who breastfeed their babies could protect themselves against heart attacks and stroke, research out today suggests.
Data carried out on 139,681 women found those who breastfed were less likely to suffer heart attacks, stroke or heart disease in later life.
Women who had breastfed their babies for more than a year were 10% less likely to develop the conditions than women who had never breastfed.
But even breastfeeding for at least a month could help cut the chances of women developing diabetes, high blood pressure and high cholesterol, which are all linked to heart disease.
The study, from experts at the University of Pittsburgh in the US, was carried out on women who had passed through the menopause. They were all asked about their earlier breastfeeding history.
On average, 35 years had passed since the women had last breastfed, suggesting the benefits of breastfeeding last many years.
One of the authors of the study, Dr Eleanor Bimla Schwarz, said: "Heart disease is the leading cause of death for women, so it's vitally important for us to know what we can do to protect ourselves.
"We have known for years that breastfeeding is important for babies' health; we now know that it is important for mothers' health as well.
"The longer a mother nurses her baby, the better for both of them.
"Our study provides another good reason for workplace policies to encourage women to breastfeed their infants."
The research was published in the journal Obstetrics and Gynaecology.
The research showed that women who had breastfed for more than a year in total were 12% less likely to have high blood pressure, around 20% less likely to have diabetes and high cholesterol, and 10% less likely to have heart disease than women who never breastfed.
The authors said: "These findings build on a growing body of literature that demonstrates that lactation has beneficial effects on blood pressure, risk of developing diabetes, and lipid metabolism."
Other studies have shown breastfeeding helps protect mothers against ovarian and breast cancer, and osteoporosis in later life. NHS experts say breastfeeding gives babies all the nutrients they need for the first six months of life.
It has also been shown to help protect infants against infections of the ear, stomach and chest. Breastfeeding also helps prevent urine infections, diabetes, eczema, obesity and asthma.
The Department of Health recommends exclusive breastfeeding for the first six months of life with additional breastfeeding while the baby moves on to solids if the mother wants to.
June Davison, cardiac nurse at the British Heart Foundation, said: "This study found that women who breastfed their children for more than a year were less likely to have high blood pressure, diabetes, hyperlipidemia and develop cardiovascular disease.
"Breastfeeding has long been thought to be beneficial to baby and mother. This research suggests that it might have also have heart health benefits for mum, too.
"However, it only showed an association between breastfeeding and these health benefits. We will need further research to understand why this is the case."