Women who breastfeed their babies can see their risk of developing diabetes later in life cut by almost half, research suggests.
A study tracking mothers over 30 years found those who breastfed even for a short while were 25 per cent less likely to get Type 2 diabetes than women who had never breastfed.
And for those who persisted for more than six months the risk dropped 47 percent.
Scientists believe this protective effect is because sugar is diverted from the blood stream into breastmilk, so less glucose is circulating in the body.
Experts have long advised women to breastfeed for the sake of their child's health, but growing evidence suggests it also has a profound impact on the mother herself.
Recent studies have shown women who breastfeed are also less likely to suffer heart attacks, strokes and even some forms of cancer.
In the study, which followed 1,200 mothers, researchers from the Kaiser Permanente Institute in California carried out blood tests every five years to check whether the women had developed diabetes.
The women, who were aged 18 to 30 at the beginning of the study, were all free of the condition at the outset. But by the end 182 had developed diabetes – 15 per cent of all participants.
The scientists found those who breastfed, rather than giving their baby formula milk, were less likely to develop the disease. And the longer they breastfed, the greater the impact. They believe this is because women who are breastfeeding have less glucose in their blood. ‘Lactating women have lower circulating glucose?...?as well as lower insulin secretion, despite increased glucose production rates,' they said.
‘About 50g of glucose per 24 hours is diverted into the mammary gland for milk synthesis.'
Women who breastfeed also lose more fat, using up an additional 300 calories a day, which may also have an impact on diabetes, they wrote in the JAMA Internal Medicine journal.
Dr Tracy Flanagan, director of women's health for Kaiser Permanente, added: ‘We have known for a long time that breastfeeding has many benefits both for mothers and babies, however, previous evidence showed only weak effects on chronic disease in women. Now we see much stronger protection?...?showing that mothers who breastfeed for months after their delivery may be reducing their risk of developing Type 2 diabetes by up to one half as they get older.'