What’s normal? Oligosaccharide concentrations and profiles in milk produced by healthy women vary geographically ,

Abstract

Background: Human milk is a complex fluid comprised of myriad substances, with one of the most abundant substances being a group of complex carbohydrates referred to as human milk oligosaccharides (HMOs). There has been some evidence that HMO profiles differ in populations, but few studies have rigorously explored this variability.Objectives: We tested the hypothesis that HMO profiles differ in diverse populations of healthy women. Next, we examined relations between HMO and maternal anthropometric and reproductive indexes and indirectly examined whether differences were likely related to genetic or environmental variations.Design: In this cross-sectional, observational study, milk was collected from a total of 410 healthy, breastfeeding women in 11 international cohorts and analyzed for HMOs by using high-performance liquid chromatography.Results: There was an effect of the cohort (P < 0.05) on concentrations of almost all HMOs. For instance, the mean 3-fucosyllactose concentration was >4 times higher in milk collected in Sweden than in milk collected in rural Gambia (mean ± SEM: 473 ± 55 compared with 103 ± 16 nmol/mL, respectively; P < 0.05), and disialyllacto-N-tetraose (DSLNT) concentrations ranged from 216 ± 14 nmol/mL (in Sweden) to 870 ± 68 nmol/mL (in rural Gambia) (P < 0.05). Maternal age, time postpartum, weight, and body mass index were all correlated with several HMOs, and multiple differences in HMOs [e.g., lacto-N-neotetrose and DSLNT] were shown between ethnically similar (and likely genetically similar) populations who were living in different locations, which suggests that the environment may play a role in regulating the synthesis of HMOs.Conclusions: The results of this study support our hypothesis that normal HMO concentrations and profiles vary geographically, even in healthy women. Targeted genomic analyses are required to determine whether these differences are due at least in part to genetic variation. A careful examination of sociocultural, behavioral, and environmental factors is needed to determine their roles in this regard. This study was registered at clinicaltrials.gov as NCT02670278.

Cross-feeding interactions of gut symbionts driven by human milk oligosaccharidesand mucins

“…Currently, over 200 HMOS structures are detected with only 50 structures accounting for 99% of the total HMOS abundance in human milk (Ninonuevo et al 2006, Smilowitz et al 2014, Wu et al 2010, Wu et al 2011. The composition of HMOS is different between individuals and is determined by maternal genetic factors (McGuire et al 2017, Thurl et al 2017. The Secretor Status (Se) and Lewis (Le) genes, which determine the blood group of humans also determine the presence or absence of some fucosylated oligosaccharides in human milk (Bode 2012).…”

“…HMOS are complex carbohydrates composed of a lactose core, which may be elongated by N-acetylglucosamine (GlcNAc), galactose and/or decorated with fucose and/or sialic acid (Smilowitz et al 2014). The composition of HMOS in human milk is highly individual driven by maternal genetic factors , McGuire et al 2017 and varies with the phases of lactation. The concentration of HMOS ranges from 23 g/L in colostrum to 7 g/L in matured human milk (Coppa et al 1993, Gabrielli et al 2011.…”

Rapid changes in Atlantic grey seal milk from birth to desertion

“…In humans, these complex sugars vary dramatically in quantity and types between mothers [12,67]. They are generally not digested to provide a neonate's energy metabolism but are instead thought to control colonisation by pathogens through interfering with their sugar-based adhesion mechanisms required for All rights reserved.…”

“…Complex sugars are abundant in the milk of many species, though not all, and are active as free or protein-linked oligosaccharides [12,[63][64][65][66]. In humans, these complex sugars vary dramatically in quantity and types between mothers [12,67].…”

“…The latter may not be digested for energy provision but instead act against colonisation by potentially pathogenic microorganisms by competitively blocking their mucous and cell surface attachment receptors [6,7]. Importantly, oligosaccharides are also important for the establishment of a gut microbiome appropriate for the neonates of a species (to both aid digestion of milk and compete with incoming pathogens), and can be heterogeneous and polymorphic between individuals [7][8][9][10][11][12]. Like the proteins present during the colostrum to mature milk transition, oligosaccharides may change in composition with time after birth, some appearing early, then disappearing, and others may show the inverse [5,13].…”