In Love with Shaping You—Influential Factors on the Breast Milk Content of Human Milk Oligosaccharides and Their Decisive Roles for Neonatal Development

Abstract

Human milk oligosaccharides (HMOs) are structurally versatile sugar molecules constituting the third major group of soluble components in human breast milk. Based on the disaccharide lactose, the mammary glands of future and lactating mothers produce a few hundreds of different HMOs implicating that their overall anabolism utilizes rather high amounts of energy. At first sight, it therefore seems contradictory that these sugars are indigestible for infants raising the question of why such an energy-intensive molecular class evolved. However, in-depth analysis of their molecular modes of action reveals that Mother Nature created HMOs for neonatal development, protection and promotion of health. This is not solely facilitated by HMOs in their indigestible form but also by catabolites that are generated by microbial metabolism in the neonatal gut additionally qualifying HMOs as natural prebiotics. This narrative review elucidates factors influencing the HMO composition as well as physiological roles of HMOs on their way through the infant body and within the gut, where a major portion of HMOs faces microbial catabolism. Concurrently, this work summarizes in vitro, preclinical and observational as well as interventional clinical studies that analyzed potential health effects that have been demonstrated by or were related to either human milk-derived or synthetic HMOs or HMO fractions.

Human Milk Oligosaccharides: A Comprehensive Review towards Metabolomics

“…However, among these, the genus Bifidobacterium soon becomes dominant. In fact, it can represent up to 90% of the microbiota of a breastfed baby while, in many formula-fed infants, they have been found in more modest quantities (about 50%), very similar to the concentrations of Bacteroides [ 45 ].…”

“…This feature seems to be the result of an intense and selective evolutionary pressure of millions of years in order to better meet the survival needs of children [ 46 ]. However, this property is not exclusive to the Bifidobacterium genus but also belongs to some species of Bacteroides , Enterococcus , Lactobacillus , Streptococcus and Clostridium cluster IV/XIVa [ 45 ]. In fact, Borewicz et al [ 47 ] showed that the degree of metabolization of oligosaccharides is closely related to the presence of the genera Bifidobacterium , Bacteroides and Lactobacillus .…”

In silico analysis of the human milk oligosaccharide glycome reveals key enzymes of their biosynthesis

“…Human milk, aside from its value as a source of food for the new-born infant, has increasingly been shown to have many additional benefits in promoting development and providing protection from diseases. Human milk oligosaccharides (HMOs) are the third most abundant constituent of milk, after lactose, and lipids, with total mean concentrations ranging from 4–30 g/L 1 . The majority of these complex oligosaccharides are based on free lactose.…”

In silico analysis of the human milk oligosaccharide glycome reveals key enzymes of their biosynthesis

“…Human milk, aside from its value as an optimal source of food for the new-born infant, has increasingly been shown to have many additional benefits in promoting development and providing protection from disease. Human milk oligosaccharides (HMOs) are the third most abundant constituent of milk, after lactose, and lipids, with total mean concentrations ranging from 4-30 g/L [1]. The majority of these complex oligosaccharides are typically based on free lactose.…”