Breastfeeding protects girls more

BALTIMORE, June 4 (UPI) -- Challenging the belief that breastfeeding equally protects all babies, U.S. researchers said the protective effects of breast milk are higher in girls.

Senior investigator Dr. Fernando Polack and colleagues of The Johns Hopkins Children's Center in Baltimore tracked 119 premature babies in Buenos Aires through their first year of life.

The study, published in the journal of Pediatrics, found formula-fed girls were eight times more likely than breast-fed girls to develop serious respiratory infections requiring hospitalization. Formula-fed girls were also more likely to develop such infections than both breastfed and non-breastfed boys.

Breastfeeding did not appear to affect the number of infections, but rather their severity and the need for hospitalization, meaning that breast milk does not prevent a baby from getting an infection, but helps a baby cope with an infection better, Polack said.

"In light of these results, we are starting to think that milk does not directly transfer protection against lung infections but instead switches on a universal protective mechanism, already in the baby, that is for some reason easier to turn on in girls than in boys," Polack said in a statement.