The infant microbiome
Infant gut microbiome colonization begins at delivery with exposure to maternal vaginal and fecal microbes or microbes from the skin, mouth, and surrounding environment in infants born by c-section delivery. After birth, infants are bombarded by a vast array of microbes found in the environment, including in breast milk, but the species that survive are often those transmitted by the infants’ mother through physical contact. Children continue to acquire gut microbiome species from their mother and others in the community during early life.
The gut microbiome is more malleable in the first 2 years after birth, allowing probiotics to make their mark. Can we exploit this to improve infants’ health?
Findings published in 2017 showed that feeding breastfed babies a probiotic that included Bifidobacterium longum subspecies infantis (B. infantis EVC001) resulted in a 10,000,000-fold average increase in levels of fecal B. infantis. This level persisted for one month after the supplement was consumed, and levels remained elevated for up to 1 year after treatment.
Colonization of the infant gut by B. infantis had protective effects, such as lower levels of gut pathogens and endotoxins known to trigger inflammation. We also found that infants given the B. infantis probiotic had reduced intestinal inflammation compared with breastfed infants who did not receive the probiotic. The decline of Bifidobacterium in infant microbiomes has been suggested as one possible contributor to the increased incidence of autoimmune diseases.
Many infants around the world never acquire B. infantis, but the combination of breastfeeding and probiotic seems to lead to a nourishing and protective gut environment.