The longer a baby is breastfed, the better it breathes - unless the mother is asthmatic - a new study says. Breastfed babies are also less liable to suffer from diarrhoea and ear infections, says the study, published in the November issue of the American Journal of Respiratory and Critical Care Medicine.
"Longer breastfeeding in infancy is associated with improved lung function in later childhood, with minimal effects on airflow in children of non-asthmatic mothers," wrote Theresa W. Guilbert of the University of Wisconsin-Madison.
"However, longer breastfeeding in children of mothers with asthma demonstrates no improved lung growth and significant decrease in airflows later in life."
Guilbert speculates that the breast milk of non-asthmatic mothers may contain certain factors that promote lung development, citing several possible candidates including cytokines, tumour necrosis factor, epithelial growth factor and prostaglandin.
"These findings suggest that growth factors in milk have the potential to modify lung development, which might account for some of the protective effect of breastfeeding against wheeze," wrote Guilbert.