Researchers have found that breast fed babies could have stronger lungs that last well into their childhood from the sheer physical effort involved in sucking milk while breast feeding. They found that children who had been breast fed for a minimum of four months had stronger lung function in later childhood.

The study published in journal Thorax, was conducted by researchers from the University of Southampton and the College of Veterinary Medicine in Michigan State University on 1456 babies from the Isle of Wight till the age of ten. A third of them had been breastfed for at least four months, and on average, these children after taking a deep breath could blow out more air and could blow it out faster. This was regardless of whether the mother was asthmatic or suffered from allergies.

 Researchers said the different mechanics and duration of sucking may be partly responsible and if this were indeed the reason then changes in the design of feeding bottles could mimic this effect.

Dr Syed Arshad, of the University of Southampton, said: "What they are doing is very similar to the kind of exercises we suggest for pulmonary rehabilitation in older patients.

"Breastfeeding for at least four months significantly increased lung function in later childhood and this effect was in addition to the reduction in wheeze, that was observed in the Isle of Wight birth cohort, in early childhood."

Breast fed babies on average need to generate three times the sucking power as compared to bottle-feeding, and feeding sessions tend to last much longer. "No-one can argue that breastfeeding is not the best for a child, but it might be possible to make a bottle for women who are unable to breast-feed," said Arshad.

Researchers from the University of Sunderland have reported that the incidence of asthma in children who were breast fed for six months or more was lower. Sally Rose, asthma nurse specialist at Asthma UK, said, "While some research does suggest that breastfeeding may help reduce the chance of babies developing allergic conditions such as asthma, there are other studies that contradict this."

"Because breastfeeding provides many proven benefits for babies, current advice from the Department of Health, which Asthma UK supports, is that where possible, babies should be exclusively breastfed for the first six months of life."

Some studies have suggested that certain immune chemicals in breast milk may give immunity against asthma, a fact that was disagreed upon by scientists from Southampton University and the College of Veterinary Medicine in Michigan State University. They reported that the changes in lung volume they found were not completely characteristic of an asthmatic response, suggesting that other factors might be at work.

Dr Elaine Vickers, from Asthma UK, said, "While the results of the study don't focus specifically on asthma, the researchers were able to demonstrate that children breast-fed for four months or longer had better lung function than those who weren't breast-fed at all, or who were breast-fed for less than four months. "We currently support advice from the Department of Health, which states that where possible, babies should be exclusively breastfed for the first six months of life."