Children who are breast fed for at least 4 months may have better lung function than children who are breast fed for shorter periods of time and children who are bottle fed, a new study suggests.
Among 10-year old children, researchers found greater lung function and capacity in those who were breast fed for 4 months or longer during infancy.
"The physical exercise caused by suckling at the breast - about six times daily on average for more than 4 months - may result in increased lung capacity and increased airflow in breast-fed children compared with bottle-fed children," Dr Ikechukwu U. Ogbuanu told Reuters Health.
How the study was conducted
Ogbuanu, of the University of South Carolina in Columbia, and colleagues studied the feeding practices of infants born in 1989 on the Isle of Wight in the United Kingdom. At the time, breast feeding was predominantly direct suckling from the breast rather than indirect feeding of pumped breast milk from a bottle, the researchers note.
Among the 1 033 children tested when they were 10 years old, 39 percent had been directly breast fed 4 months or longer. About 40 percent of the children had been breast fed for less than 4 months. Another 21 percent were not breast fed and therefore comprised the bottle-fed group.
Standard tests showed that the lungs of children who were breast fed for 4 months or longer were stronger than the lungs of children who were bottle-fed.
The researchers noted no beneficial effects on lung function from shorter duration breast feeding.
The statistically significant increase in lung capacity among children breast fed for 4 months or longer is likely related to the physical exercise from breast feeding, the investigators say.
"At lease some of the benefits from breast milk may accrue from the process of suckling itself," noted Ogbuanu. This concept is supported by other studies noting suckling exercise is nearly twice as long during breast feeding compared with bottle feeding, and that breast feeding requires more "ventilatory" effort.
SOURCE: Thorax, January 2009.
(Reuters Health, January 2009)