Breast-fed babies are less likely to be obese or have heart disease in later life than those who were bottle-fed, say researchers.

In a large US study, middle-aged adults who were breast-fed as infants were found to be 55 per cent more likely to have high levels of high-density lipoprotein (HDL), the so-called “good” cholesterol that protects against cardiovascular disease (CVD).

They also had a lower average body mass index (BMI) score - 26.1 kg/m2 compared with 26.9 - than those who were not breast-fed. A BMI score of more than 25 is considered to be overweight and a risk factor for heart disease. “This was a modest reduction in BMI, but even a modest reduction leads to a significantly reduced risk of cardiovascular disease-related death,” the researchers say.

The study, reported yesterday at a meeting of the American Heart Association in Orlando, Florida, included 393 mothers enrolled in the continuous Framingham Offspring Study and 962 of their offspring. The average age of the offspring was 41 and 54 per cent were women.

Although previous studies have hinted that breast-feeding produces health benefits in later life, much of the existing research was limited by a lack of adjustment for other factors, such as socioeconomic status.

Britain has one of the lowest breast-feeding rates in the industrialised world. Initiation rates currently stand at 76 per cent, meaning that a quarter of infants receive no breast milk at all.

Nisha Parikh, who led the latest study at the Beth Israel Deaconess Medical Centre, in Boston, Massachusetts, said that having been breast-fed in infancy was associated with longer-term health benefits “even after accounting for personal and maternal demographic and CVD risk factors that could influence the results”. Research also suggests that babies who are not breast-fed have a higher risk of infection.

Dr Parikh said that she had the idea for the study after returning from maternity leave. “The benefits of breast-feeding in infancy and childhood are well established. But I wondered if it were as helpful for health in adulthood,” she said.

For the study, mothers reported whether they breast-fed each of their children and for how long. Overall, 26 per cent of the participants’ offspring were breast-fed.

After adjustment for factors including use of blood-pressure-lowering medication, maternal education, smoking and body mass index, breast-fed offspring had higher than average HDL-cholesterol levels in adulthood: 56.6 mg/dL compared with 53.7 mg/dL for the bottle-fed participants. HDL bonds with and transports cholesterol particles in the blood stream, and as such protects against heart disease and stroke by preventing blood vessels from becoming blocked and furred up (atherosclerosis). Lower HDL-borne cholesterol levels are known to increase the risk of heart disease.

“The findings show that early environmental exposures have long-term health effects,” Dr Parikh added. “They also underscore that atherosclerosis and cardiovascular disease are life-course diseases that have their roots early in life.”

Rosie Dodds, policy researcher for the National Childbirth Trust, said that the findings concurred with the World Health Organisation’s own research into the long-term effects of being breast-fed as a child.

“This study provides more evidence of the difference breast-feeding makes to blood pressure, obesity, diabetes and cholesterol levels,” she said.

“Women should be free to choose whether they breast-feed or not, but they should also have access to good information and support about their options. At the moment, that is what they are not getting in this country.”

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