A child breastfeeding.

Scientists say that some components in breast milk could help guard against HIV transmission from mother to child.

In a paper published Wednesday in the American Journal of Clinical Nutrition, an international team of researchers say that higher concentrations of human milk oligosaccharides, or HMO -- a kind of complex carbohydrate that's the third-most abundant ingredient in breast milk -- were associated with protection against HIV transmission in a group of Zambian mothers.

"In developing countries, HIV-infected mothers are faced with the decision of whether or not to breastfeed their babies," lead author and University of California San Diego researcher Lars Bode said in a statement Wednesday. "Breastfeeding exposes the baby to the virus and increases the risk of the baby dying from HIV infection; but not breastfeeding increases the risk for the baby to die from other intestinal or respiratory infections."

Bode and his colleagues were interested in figuring out why 85% to 95% of breast-fed infants with HIV-positive mothers do not acquire the virus.

The researchers analyzed breast milk samples from 81 HIV-infected women that transmitted the virus to their infants, 86 HIV-infected mothers that did not transmit the virus through breastfeeding, and 36 uninfected breastfeeding mothers. They found that HIV-infected women with total HMOs above the median level were less likely to transmit the virus to their babies.

According to Bode, HMO can promote the growth of beneficial bacterial communities in a baby's intestine. These molecules may also foil HIV because they resemble certain sugars found on the surfaces of the baby's cells that the virus binds to. HMO also have been shown to inhibit inflammation and play a role in immune system responses.

The authors did note that their study focused on HMO, and that other milk bioactive compounds other could also decrease the risk of HIV transmission through breastfeeding.

SOURCE: Bode et al. "Human milk oligosaccharide concentration and risk of postnatal transmission of HIV through breastfeeding." Am J Clin Nutr published ahead of print 15 August 2012.