(SACRAMENTO, Calif.) -- Researchers at UC Davis have found that a gene, which is not active in some mothers, produces a breast milk sugar that influences the development of the community of gut bacteria in her infant. The sugars produced by these mothers, called "secretors," are not digested by the infant, but instead nourish specific bacteria that colonize the babies' guts soon after birth.

Mothers known as "non-secretors" have a non-functional fucosyltransferase 2 (FUT2) gene, which alters the composition of their breast milk sugars and changes how the microbial community, or microbiota, of their infants' guts develop.

The research may have applications in a clinical setting for protecting premature infants from a range of intestinal diseases including necrotizing enterocolitis (NEC), a condition that is the second most common cause of death among premature infants in the United States.

The researchers emphasized that the finding does not suggest that breast milk from mothers without an active copy of the gene is less nourishing or healthy. Rather, it conveys the subtle and elegant choreography of one part of the human microbiome: The relationships between the mothers' genetics, the composition of her breast milk and the development of her infant's gut microbiota. It also reveals clues for enriching desirable bacteria in populations at risk of intestinal diseases -- such as preemies.

"In no way is the nonsecretor mother's milk less healthy, and their babies are at no greater risk," said David Mills, Peter J. Shields Endowed Chair in Dairy Food Science at UC Davis and senior study author. "What this work does show us is that the mother's genotype matters, and that it influences the breast milk, which clearly drives the establishment of microbes in the intestines of their babies."

The research examining the differences in infant gut microbial populations arising from differences in human milk oligosaccharides (sugars), "Maternal Fucosyltransferase 2 Status Affects the Gut Bifidobacterial Communities of Breastfed Infants," is published online today in the journal Microbiome, a BioMedCentral journal.

Varieties of Bifidobacterium inhabit the gastrointestinal tracts and mouths of mammals and are one of the major genera of bacteria that make up the microbial community of the infant colon. The relationship between human genetics, breast milk and Bifidobacterium appears to have developed throughout mammalian evolution.

Development of a healthy gut microbiota can have a lifelong effect on health, and early intervention in the establishment of that microbiota could have lifelong positive effects: The early establishment of bifidobacteria has been shown to be associated with improved immune response to vaccines, development of the infants' immature immune system, and protection against pathogens.

Bifidobacterium are known to consume the 2'-fucosylated glycans (sugars) found in the breast milk of women with the fucosyltransferase 2 mammary gene. The study found that, on average, Bifidobacterium were established earlier and more frequently in infants fed by women with an active copy of the gene, the secretors, than without one, the non-secretors.

The authors found that the intestinal tracts of infants fed by non-secretor mothers are delayed in establishing a bifidobacteria-dominated microbiota. The delay, the authors said, may be due to difficulties in the infant acquiring a species of bifidobacteria that is geared toward consuming the specific milk sugar delivered by the mother.

Originally posted here:
A mother's genes can influence the bacteria in her baby's gut

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