ScienceDaily (Nov. 24, 2010) — Infants are more efficient at digesting and utilizing nutritional components of milk than adults due to a difference in the strains of bacteria that dominate their digestive tracts.
Researchers from the University of California, Davis, and Utah State University report on genomic analysis of these strains in the November 2010 issue of the journal Applied and Environmental Microbiology identifying the genes that are most likely responsible for this difference.
"Human milk oligosaccharides (HMOs) are the third-largest solid component of milk. Their structural complexity renders them non-digestible to the host," say the researchers. "Bifidobacterium longum strains often predominate the colonic microbiota of exlusively breast-fed infants. Among the three recognized subspecies, B. longum subsp. infantis achieves high levels of cell growth on HMOs and is associated with early colonization of the infant gut."