Breast Milk, a Source of Beneficial Microbes and Associated Benefits for Infant Health

Abstract

Human breast milk is considered the optimum feeding regime for newborn infants due to its ability to provide complete nutrition and many bioactive health factors. Breast feeding is associated with improved infant health and immune development, less incidences of gastrointestinal disease and lower mortality rates than formula fed infants. As well as providing fundamental nutrients to the growing infant, breast milk is a source of commensal bacteria which further enhance infant health by preventing pathogen adhesion and promoting gut colonisation of beneficial microbes. While breast milk was initially considered a sterile fluid and microbes isolated were considered contaminants, it is now widely accepted that breast milk is home to its own unique microbiome. The origins of bacteria in breast milk have been subject to much debate, however, the possibility of an entero-mammary pathway allowing for transfer of microbes from maternal gut to the mammary gland is one potential pathway. Human milk derived strains can be regarded as potential probiotics; therefore, many studies have focused on isolating strains from milk for subsequent use in infant health and nutrition markets. This review aims to discuss mammary gland development in preparation for lactation as well as explore the microbial composition and origins of the human milk microbiota with a focus on probiotic development.

Dietary Prevention of Atopic March in Pediatric Subjects With Cow's Milk Allergy

“…Breastfeeding shapes infant GM, both by direct transition of the human milk bacteria (HMBs), and indirectly through milk compounds such as human milk oligosaccharides (HMOs), secretory IgA, and antimicrobial factors, which could impact bacterial growth and metabolism (40). Studies have suggested that breast milk owns unique microbiome, including beneficial commensal and potentially probiotic bacteria (41). HMBs can originate from maternal skin, newborn oral cavity, or mostly from the maternal gut (the "entero-mammary pathway") and are influenced by mode of delivery, with a lower bacteria variety and abundance in cesarean compared to vaginal delivery (42,43).…”

“…Interestingly, one recent study highlighted the ability of specific HMOs, pulled from human milk, to induce the maturation of human monocyte-derived dendritic cells (DC) (moDC). The derived HMO moDC are able to promote T reg induction from native CD4 + T cells, with a final tolerogenic effect on the infant's immune system ( 49 ); but the best characterized HMO properties are related to the prebiotic modulation of early microbial gut colonization with bifidobacteria and lactobacilli , which are involved in the production of tolerogenic metabolites short-chain fatty acids (SCFA), in particular, butyrate ( 41 , 50 – 54 ). Supporting this view, it has been reported that the GM of allergic infants lacks genes encoding key enzymes for HMO metabolization with the consequent impairment of butyrate production ( 55 ).…”

Gut Microbiome Modulation for Preventing and Treating Pediatric Food Allergies

“…In contrast, cesarean section delivery, prenatal and early-life exposure to antibiotics, gastric acidity inhibitors, antiseptic agents, and junk-food-based and/or low-fiber/high-fat diets may increase the risk of FA development. These environmental factors are mostly related to the structure and function of the gut microbiome [ 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ] ( Figure 2 ).…”

<p>Dynamic Interplay Between Microbiota and Mucosal Immunity in Early Shaping of Asthma and its Implication for the COVID-19 Pandemic</p>

“…68,69 Besides transferring microbes, breast milk provides other prebiotics that support beneficial bacterial colonization. 70 For example, Bifidobacteria, Bacteroides, and Lactobacillus are adapted to utilize human milk oligosaccharides (HMOs), while these complex glycans inhibit the growth of other harmful bacteria. 71,72 Furthermore, HMOs can prevent pathogen adhesion to intestinal epithelium by serving as soluble glycan receptor decoys.…”