Microbiota From Human Infants Consuming Secretors Mothers' Milk Affects Murine Intestinal Motility and Enteric Nervous System Development in a Sex-Dependent Manner.
Kumar B, Caputi V, et al. • Neurogastroenterology and motility • 2026
Infant-derived microbiomes from secretor-mother milk, non-secretor-mother milk, or cow's milk formula exert sex-specific effects on ENS neuronal phenotypes and GI motility in germ-free mice, with female mice receiving secretor-milk microbiota showing higher distal GI transit and more nitrergic neurons.
Key Findings
Results
Female germ-free mice colonized with microbiota from infants of secretor mothers (SMM) had higher distal GI transit efficiency than sex-matched controls and than males.
Male and female juvenile (3-week-old) C57BL/6 germ-free mice were colonized with fecal microbiota from infants consuming secretor mothers' milk (SMM), non-secretor mothers' milk (NSM), or cow's milk formula (MFM).
GI transit was assessed at post-natal day 35-37.
Non-transplanted germ-free mice of each sex served as controls.
The lay summary states that the increase in large-intestinal motility was not seen in males.
Results
Female mice receiving SMM microbiota had a higher proportion of nitrergic neurons in the myenteric plexus than sex-matched controls and males.
ENS neuronal organization was evaluated in full-thickness colon preparations using immunohistochemistry and confocal microscopy.
Nitrergic neurons are specifically named as increased in SMM females; the change was not seen in males.
What This Means
This study asked whether bacteria from infants fed different types of milk can influence gut movement and the nerves of the gut. Researchers transferred gut bacteria from infants into young germ-free mice. The infants had been fed milk from mothers who were "secretors" (whose milk contains the sugar 2'-fucosyllactose), milk from non-secretor mothers, or cow's milk formula.
The effects differed by sex. Female mice that received bacteria from infants of secretor mothers moved material through the lower gut more efficiently and had a higher proportion of a particular type of gut nerve cell (nitrergic neurons). A marker of excitatory gut neurons (ChAT) was higher in germ-free females than males at baseline, and the microbiota changed it in opposite directions in the two sexes: it increased in males given secretor-milk or formula microbiota, but dropped in females given non-secretor-milk or formula microbiota. Gut support cells called glia were not affected by the infant microbiota, though they were more abundant in males than females in all groups.
This research suggests early feeding may shape gut microbes in ways that affect gut nerve development and function, and that the outcome may depend on sex. The work was done in mice, so it does not show the same effects occur in people. The authors say larger cohorts are needed to investigate this link further.
Kumar B, Caputi V, Gill K, Nanduri B, Leroith T, Fox R, et al.. (2026). Microbiota From Human Infants Consuming Secretors Mothers' Milk Affects Murine Intestinal Motility and Enteric Nervous System Development in a Sex-Dependent Manner.. Neurogastroenterology and motility. https://doi.org/10.1111/nmo.70475