Per- and polyfluoroalkyl substances and the gut microbiota in infants: A scoping review.
Level 5 - mechanism / opinion, no new human data
Scoping review of observational studies without quantitative meta-analysis
PubMed 40998209 · doi:10.1016/j.envres.2025.122937
What was done
A scoping review searched PubMed for epidemiological studies evaluating associations between per- and polyfluoroalkyl substances (PFAS) exposure and infant gut microbiota composition. Seven studies met inclusion criteria, with sample sizes ranging from 30 to 789 subjects. PFAS concentrations (most frequently PFOS and PFOA) were measured in breast milk, maternal blood, or umbilical cord blood. Infant gut microbiota was assessed using 16S rRNA sequencing or shotgun metagenomics.
What was found
The abstract reports mixed directions of association across the seven studies without numeric effect estimates, confidence intervals, or p-values. PFAS exposure was associated with both increased and decreased alpha-diversity, as well as beta-diversity shifts in some studies. Reported taxon-level changes included increased Enterococcus and decreased Faecalibacterium and Phocaeicola vulgatus. Functional pathway alterations included disrupted bile acid metabolism.
Why it matters
Infancy is a critical window for gut microbiome assembly and immune development. This review synthesizes early human evidence suggesting environmental PFAS exposure may alter infant microbial community structure and metabolic pathways.
Limits
The review is limited to seven studies, some with sample sizes as small as 30 subjects. Findings showed substantial inconsistency, notably conflicting directions for alpha-diversity. Included studies differed in exposure biological matrices (breast milk, maternal blood, or cord blood), sequencing technologies, and covariate adjustment strategies. No quantitative meta-analysis was performed.