Original title: Before the Gut: Human Milk Oligosaccharides and Oral Microbial Colonization in Infancy
Human milk contains special sugars called HMOs, which reach a baby’s mouth before the gut and resist breakdown by saliva. This review finds only two human analyses linking HMOs to infant mouth bacteria, and the larger one found a statistically detectable but biologically limited effect. Lab tests found that some milk sugars affected a cavity-linked bacterium, but only at levels far above likely exposure in the mouth. The review suggests several possible ways HMOs could affect microbes, but says the evidence is not strong enough to change feeding advice.
Imagine setting out snacks for guests who pass through your kitchen. Some snacks may stick to the plates, while others may feed certain guests, but the guests do not stay long. In this paper, the mouth is the kitchen, milk sugars are the snacks, and the brief visit makes it hard to know which microbes they affect. Lab tests show some effects, but at amounts far higher than the mouth is likely to encounter.
Infant feeding and early oral microbes matter to families and clinicians, but this review finds too little evidence to change advice about breastfeeding, formula, donor milk, or colostrum. It also points to a key gap: the baby’s own genes may shape the saliva that milk sugars encounter.
Human evidence comes from only two analyses, both in the same Western Australian cohort, and the larger found a biologically limited effect. The lab effects were seen at concentrations well above plausible oral exposure. Infant oral microbiome studies have not measured maternal and infant FUT2 genotypes, and proposed effects on commensal versus cariogenic streptococci and on gut colonization remain hypotheses. The review supports no change in feeding practice.
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Before the Gut: Human Milk Oligosaccharides and Oral Microbial Colonization in Infancy — Oana Raluca Temneanu, Felicia Trofin, Adriana Mihai et al. — Nutrients — doi:10.3390/nu18193269
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.