Six months of breast milk best for babies

Babies are less likely to develop a respiratory or gastrointestinal infection if they are exclusively breastfed for at least 6 months, according to a Dutch study.

These findings, reported in the journal Pediatrics, support the World Health Organization (WHO) recommendation that infants be breastfed exclusively for 6 months and support "current health-policy strategies that promote exclusive breastfeeding for 6 months in industrialized countries," the researchers conclude.

Dr. Henriëtte A. Moll and colleagues at the Erasmus Medical Center in Rotterdam analyzed health data on roughly 4,100 infants born in Rotterdam between 2002 and 2006.

They looked at whether the babies were breast fed, and until what age; whether they were given other foods and at what age, and whether they were treated for any common infections such as serious colds, ear or throat infections, pneumonia, bronchitis, or stomach flu.

In the first 6 months of life, nearly half of all the infants had a respiratory tract infection and nearly 8 percent had a gastrointestinal infection. Between 7 months and a year, 37 percent of the infants had a respiratory tract infection and 9 percent had a stomach bug.

"We observed protective effects of breastfeeding on infectious diseases mainly in the first 6 months of life," the researchers report. "Exclusive breastfeeding until age 6 months tended to be more protective, than exclusive breastfeeding until age 4 months."

In the first 6 months, exclusive breastfeeding cut the risk of respiratory tract infections by about two-thirds, while exclusive breastfeeding for 4 months cut the risk by one third to a half. The reduction in risk from exclusive breastfeeding for 6 months was less pronounced in the second half of the first year of life.

Exclusive breastfeeding - whether 4 or 6 months - appeared to have a less dramatic effect in reducing the risk of developing gastrointestinal infections, especially in the second half of the first year.

The study pulled data from a large population of children that allowed the researchers to adjust for factors that could have an impact on infection rates such as family history of asthma, mite allergies, and smoking in the household.

Breastfeeding rates have been trending upward since 1993 in the United States, with the steepest jump seen most recently among African American women. According to the Centers for Disease Control and Prevention, 77 percent of infants born between 2005 and 2006 were breastfed at some point compared to 60 percent in 1993.

The largest drop-off in breastfeeding occurs when women return to work, a fact Moll believes must be addressed by "translating the study results into practice."

She favors extending maternity leave to 4 to 6 months after the birth of a child and creating for working women "adequate facilities to continue breastfeeding." Failing that, breast pumps can be used to express mother's milk for use later.