Human Milk Microbiome and Microbiome-Related Products: Potential Modulators of Infant Growth

Abstract

Infant growth trajectory may influence later-life obesity. Human milk provides a wide range of nutritional and bioactive components that are vital for infant growth. Compared to formula-fed infants, breastfed infants are less likely to develop later-onset obesity, highlighting the potential role of bioactive components present in human milk. Components of particular interest are the human milk microbiota, human milk oligosaccharides (HMOs), short-chain fatty acids (SCFAs), and antimicrobial proteins, each of which influence the infant gut microbiome, which in turn has been associated with infant body composition. SCFAs and antimicrobial proteins from human milk may also systemically influence infant metabolism. Although inconsistent, multiple studies have reported associations between HMOs and infant growth, while studies on other bioactive components in relation to infant growth are sparse. Moreover, these microbiome-related components may interact with each other within the mammary gland. Here, we review the evidence around the impact of human milk microbes, HMOs, SCFAs, and antimicrobial proteins on infant growth. Breastfeeding is a unique window of opportunity to promote optimal infant growth, with aberrant growth trajectories potentially creating short- and long-term public health burdens. Therefore, it is important to understand how bioactive components of human milk influence infant growth.

Human Milk Bioactive Components and Child Growth and Body Composition in the First 2 Years: A Systematic Review

“…Our ability to synthesize and interpret research findings was tempered by substantial variation in HM sampling times and collection strategies. Inconsistent findings related to HMO composition and infant growth were similarly related to inconsistent sampling time points and reporting in a recent review of microbiome-related products in HM and infant growth [ 115 ]. It is well established that HM composition changes throughout the day and over the course of lactation for some components [ 116 ].…”

Sex differences in the associations of human milk oligosaccharides with height and weight in breastfed Ugandan children

“…It is plausible that, in our study population, HMOs affected children’s growth through microbiota-induced modulation of immunity, which reduced morbidity and thereby promoted changes in HAZ, WAZ and WHZ scores, as proposed [35]. Second, the associations between maternal secretor status and infant microbiota composition [35,36] and between infant microbiota and infant growth [25] may explain the observed differences in the associations between some HMOs and weight and height in children of secretor and nonsecretor mothers. Finally, there are sex differences in the gut microbiota composition of male and female children under 5 years old [33,38,39,40,41], which probably determines how the microbiota and HMOs interact to regulate growth in male and female Uganda children.…”

“…Studies in various countries have demonstrated an association between HMO concentrations or uptake and growth in children [20,21,22,23,24,25]. Lagstrom et al (2020) showed that the concentrations of lacto-N-neo-tetraose (LNnT) and 2'FL were inversely and directly associated with height and weight, respectively, among children of Finnish secretor mothers [20].…”

Maternal Diet May Modulate Breast Milk Microbiota—A Case Study in a Group of Colombian Women

“…and Streptoccocus spp. were reported as the dominant genera [ 46 ], which could suggest that regardless of the geographical location of the lactating woman, both genera are represented in this fluid and their colonization could be linked to the retrograde flow from the oral cavity of the infant [ 47 ]. Some Streptococcus spp.…”