New York, Oct 29 (IANS): The road to obesity may be paved with non-nutritious carbohydrates in breast milk, claims new research.

Previous research has shown that maternal obesity strongly affects a baby's risk for becoming overweight, but scientists are unsure about how fatness is transmitted, said corresponding author Michael Goran, Keck School of Medicine, University of Southern California.

The new study showed that variations in complex carbohydrates found in breast milk called human milk oligosaccharides (HMOs) are associated with variations in infant growth and obesity.

HMOs, a natural component of breast milk, are known to play a role in helping to develop the infant immune system.

"Increased amounts of a HMO called LNFPI in breast milk was associated with about a one-pound lower infant weight and fat mass," lead study author Tanya Alderete from the University of Southern California noted.

"At six months of age, higher breast milk levels of LNFPII and DSLNT were each associated with approximately one pound of greater fat mass," Alderete said.

The study examined 25 mother-infant pairs and looked at breast milk and infant measures at ages one and six months.

"Ultimately what we would like to be able to do is identify which of the HMOs are most important for obesity protection and then use that as a supplement that can be given to the breastfeeding infant and added to infant formulae," Goran said, noting that current infant formulae do not contain any HMOs.

While genetics play a role in HMO composition, scientists do not yet know what contributes to variation in the composition of breast milk, Goran said.

The study was published online in The American Journal of Clinical Nutrition.