1. Introduction
milk, Human Milk Oligosaccharides (HMOs)., immature gastrointestinal tract, gastrointestinal tract
Human milk represents an optimal source of nutrition during infancy. Milk also serves as a vehicle for the transfer of growth factors, commensal microbes, and prebiotic compounds to the immature gastrointestinal tract. These immunomodulatory and prebiotic functions of milk are increasingly appreciated as critical factors in the development of the infant gut and its associated microbial community. Advances in infant formula composition have sought to recapitulate some of the prebiotic and immunomodulatory functions of milk through human milk oligosaccharide (HMO) fortification, with the aim of promoting healthy development both within the gastrointestinal tract and systemically. Our objective was to investigate the effects of feeding formulas supplemented with the HMO 2′-fucosyllactose (2′-FL) on serum metabolite levels relative to breastfed infants. A prospective, randomized, double-blinded, controlled study of infant formulas (64.3 kcal/dL) fortified with varying levels of 2′-FL and galactooligosaccharides (GOS) was conducted [0.2 g/L 2′-FL + 2.2 g/L GOS; 1.0 g/L 2′-FL + 1.4 g/L GOS]. Healthy singleton infants age 0–5 days and with birth weight > 2490 g were enrolled (Medical consensus has long held that exclusive breastfeeding is the best source of nutrition and immune protection during early life. Exclusive breastfeeding through 12 months of age is strongly encouraged by prominent medical advisory groups including the American Academy of Pediatrics [Significant progress has been made in recent years regarding the fortification of some infant formulas with Human Milk Oligosaccharides (HMOs). HMOs are the 3rd largest solid component of human milk with a broad range of potential benefits, including prebiotic effects and enhanced gut maturation, gut motility, immunity, and cognition [Recent improvements in the efficiency of HMO synthesis have allowed for the production of HMOs on an industrial scale, making supplementation of infant formula with oligosaccharides that are chemically and structurally identical to those found in human milk more feasible [HMOs, including 2′-FL, readily cross the epithelium of the gastrointestinal tract [