Lower rates of breastfeeding may help explain why minority and disadvantaged U.S. children are at greater risk of becoming overweight, a new study suggests.

Researchers found that among 739 10- to 19-year-olds, those who had been breastfed for more than four months had a lower average body mass index (BMI), and lower odds of being overweight.

This was true regardless of race or parents’ education levels, the researchers report in the journal Pediatrics. However, the study found, there were disparities when it came to rates of breastfeeding; 40 percent of white adolescents but only 11 percent of black children had been breastfed for at least four months.

There was a similar difference when the researchers looked at parents’ education levels, a marker of socioeconomic status. Forty percent of children with college-educated parents had been breastfed for at least four months, versus 18 percent of those with less-educated parents.

“This really does suggest that if we could somehow increase the frequency and duration of breastfeeding in these groups, we could reduce disparities in (obesity),” said researcher Dr. Jessica G. Woo of Cincinnati Children’s Hospital.

A number of previous studies have suggested that breastfeeding may lower children’s risk of becoming overweight later in life, though some others have found no such relationship. There are several theories on why breastfeeding might directly affect childhood weight gain, Woo told Reuters Health.

One is that, compared with bottle-feeding, breastfeeding allows infants to have more control over how much they eat; this may have lasting effects on children’s ability to self-regulate their calorie intake.

Researchers also speculate that breast milk itself may have lasting metabolic effects that aid in weight control.

The bottom line, according to Woo, is that, whatever the effects on children’s weight, breastfeeding has many potential benefits for children and mothers.

Breastfed babies have a lower risk of illnesses like diarrhea and middle-ear infections, and breastfeeding has also been linked to lower odds of allergies, asthma and childhood leukemia.

The American Academy of Pediatrics and other professional groups recommend that babies be breastfed exclusively for the first six months of life. This, Woo said, “is a goal that everyone should strive for.”

She suggested that women who are having difficulty breastfeeding talk to their doctors and seek out local resources for help. Many health clinics and hospitals, for example, have lactation specialists who help new mothers get past the obstacles to breastfeeding.

SOURCE: Pediatrics, March 2008.