The sheer physical effort involved in breastfeeding
may leave babies with stronger lungs well into childhood,
A study of 10-year-olds on the Isle of Wight by UK and US
scientists found much better lung function in those breastfed
for at least four months.
The different mechanics and duration of sucking may be partly
responsible, they said, in the journal Thorax.
If so, changes to the design of bottles could mimic this
Studies have established that breastfeeding protects babies
from respiratory problems early in life, but the relationship
with lung power later in childhood is less clear-cut.
A total of 1,456 babies from the Isle of Wight were followed
all the way through to their 10th year to test this.
A third of them had been breastfed for at least four months,
and on average, these children could blow out more air after
taking a deep breath, and could blow it out faster.
This happened regardless of whether their mother was asthmatic
or suffered from allergies.
The reason for these benefits was not as obvious, the researchers
Other studies have suggested that immune chemicals in breast-milk
may have a protective effect against asthma.
However, the scientists from Southampton University and the
College of Veterinary Medicine in Michigan State University,
said 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 Syed Arshad, from Southampton and the David Hide Asthma
and Allergy Research Centre on the Isle of Wight, said that
the physical effort needed to extract milk from the breast
might be involved.
On average, babies needed to generate three times the sucking
power compared to bottle-feeding, and feeding sessions tended
to last much longer.
Dr Arshad said: "What they are doing is very similar to the
kind of exercises we suggest for pulmonary rehabilitation
in older patients.
"I'm not aware of anyone suggesting that this might be the
The research team has now approached a bottle manufacturer
with proposals to create a bottle which mimics the effort
needed to breastfeed.
He said that it was now possible to carry out lung function
tests on infants, which meant that a trial to see if it made
a difference could be concluded within a year.
"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."
Dr Elaine Vickers, from Asthma UK, said that the study added
to the evidence that breastfeeding has "long-lasting benefits"
She 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."