2019 Volume 33 Issue 1 Pages 1-14
Human breast milk is considered to be the best nutritional source for newborns. The gut microbiota of infants is generally dominated by bifidobacteria, and this bifidobacteria-enriched gut microbiota is thought to confer many health benefits to infants. Human breast milk contains various bioactive factors such as antibacterial, immunological and bifidogenic factors that could potentially modulate the gut microbiota. These bioactive factors may act as selective substrates for the enrichment of bifidobacteria in the infant gut via coordinated, complex mechanisms; however, the details of these mechanisms have not been fully elucidated. It has also been reported that the gut microbiota of formula-fed infants is different from that of breastfed infants with bifidobacteria being less abundant in formula-fed infants. Thus, a lot of effort has been paid to the development of an infant formula which nourishes formula-fed infants and establishes a bifidobacteria-dominated gut microbiota similar to that of breastfed infants. In this review, we present recent findings on how human milk promotes the growth of “infant-type” bifidobacteria and excludes other bacteria in the infant gut, focusing on human milk oligosaccharides (HMOs), which are major bifidogenic factors in human milk. We also summarize the history, current status and future outlook of the development of infant formula from the viewpoint of gut microbiota improvement.
