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Open AccessVollständige AnalyseJun 16, 2026

Distinct microbiota and short-chain fatty acid patterns in breast milk and infant gut from rural and urban dyads

Rural infants show greater gut microbiota maturity at 0–2 months, but urban infants surpass them at 6–12 months, with location-specific microbial succession trajectories.

The question (PICO)
Population69 mother–infant dyads (infants 0–12 months) in Manitoba, Canada, including 10 mothers with gestational diabetes, stratified by rural or urban residence
InterventionRural residence (environmental exposure)
VergleichUrban residence
EndpunktInfant gut and breast milk microbiota composition and maturity (16S rRNA); SCFA profiles in stool and milk (GC-MS); milk–gut microbiota correlations
CEvidenz
Studie
Observational study
Stichprobe
69
Effekt
Unzureichend
Dauer
12 Monate
Zusammenfassung der Ergebnisse nach Endpunkt
EndpunktGradRichtungEffektStudien
Infant gut microbiota maturity (0–2 months)C GünstigRural > urbano; sem IC 95% ou tamanho de efeito reportado1
Infant gut microbiota maturity (6–12 months)C GünstigUrbano > rural; sem IC 95% ou tamanho de efeito reportado1
Mature milk microbiota composition (Veillonella, Alistipes, isobutyric acid)C UnzureichendUrban > rural Veillonella/Alistipes; rural > urban isobutyric acid; sem IC 95%1
Fecal SCFAs in rural infants (acetic acid)C UnzureichendRural > urbano; sem IC 95% ou tamanho de efeito reportado1
Fecal SCFAs in urban infants (valeric acid)C UnzureichendUrbano > rural; sem IC 95% ou tamanho de efeito reportado1
Alistipes milk–stool correlation (urban dyads)C GünstigCorrelação significativa apenas em díades urbanas; sem IC 95% ou r reportado1
Blautia milk–gut sharing (rural dyads)C GünstigObservado apenas em díades rurais; sem IC 95% ou tamanho de efeito reportado1
Infant gut microbiota maturity (0–2 months)C
Richtung Günstig
EffektRural > urbano; sem IC 95% ou tamanho de efeito reportado
Studien1
Infant gut microbiota maturity (6–12 months)C
Richtung Günstig
EffektUrbano > rural; sem IC 95% ou tamanho de efeito reportado
Studien1
Mature milk microbiota composition (Veillonella, Alistipes, isobutyric acid)C
Richtung Unzureichend
EffektUrban > rural Veillonella/Alistipes; rural > urban isobutyric acid; sem IC 95%
Studien1
Fecal SCFAs in rural infants (acetic acid)C
Richtung Unzureichend
EffektRural > urbano; sem IC 95% ou tamanho de efeito reportado
Studien1
Fecal SCFAs in urban infants (valeric acid)C
Richtung Unzureichend
EffektUrbano > rural; sem IC 95% ou tamanho de efeito reportado
Studien1
Alistipes milk–stool correlation (urban dyads)C
Richtung Günstig
EffektCorrelação significativa apenas em díades urbanas; sem IC 95% ou r reportado
Studien1
Blautia milk–gut sharing (rural dyads)C
Richtung Günstig
EffektObservado apenas em díades rurais; sem IC 95% ou tamanho de efeito reportado
Studien1

Kontext

Early-life gut microbiota composition influences long-term metabolic and immune outcomes. The effect of rural versus urban residence on the breast milk–infant gut axis is poorly characterized. Understanding these differences may inform context-specific breastfeeding support strategies.

Was die Studie zeigte

Rural infants had higher gut microbiota maturity at 0–2 months; urban infants exceeded rural infants at 6–12 months, indicating distinct succession trajectories. Rural infant stool contained higher Faecalibacterium, Odoribacter, and acetic acid; urban stool contained higher Bacteroides, Akkermansia, Ruminococcaceae, and valeric acid. Urban mature milk had higher Veillonella and Alistipes and lower isobutyric acid than rural milk. A significant Alistipes correlation between milk and stool was detected in urban dyads; Blautia milk–gut sharing was observed in rural dyads. The study did not report absolute counts, 95% CIs, or standardized effect sizes for most outcomes.

Wie es durchgeführt wurde

Observational cross-sectional/longitudinal study of 69 mother–infant dyads in Manitoba; stool collected from 0–12 months and breast milk from 1–30 days postpartum. Microbiota analyzed by 16S rRNA sequencing; SCFAs by GC-MS. No sample size calculation or formal risk-of-bias tool was reported.

Effektgröße

No standardized effect sizes (SMD, OR, RR) or 95% CIs were reported for the main comparators; differences are described as 'significant' without complete quantitative metrics, preventing precise magnitude assessment.

Einschränkungen

Small sample (n=69) without reported power calculation limits generalizability. Observational design precludes causal inference between location and microbial outcomes. No formal risk-of-bias tool applied (e.g., ROBINS-I). Inclusion of 10 mothers with gestational diabetes without complete stratification is a confounding factor. Milk collection restricted to 30 days postpartum does not capture prolonged exposure. Confounders (maternal diet, antibiotic use, delivery mode, complementary feeding) may not be fully controlled.

In der klinischen Praxis

Clinicians should not translate these findings into individual clinical recommendations given the study's size and design. Geographic context (rural/urban) may be recorded as a relevant variable in future infant microbiota research. Breastfeeding support tailored to local environmental conditions may be warranted, but this is not supported by clinical trial evidence.

Was noch fehlt

Longitudinal studies with larger samples, rigorous confounder control (diet, antibiotics, delivery mode), and clinical health outcomes (allergies, obesity, infections) are needed to establish causality and clinical relevance of the observed differences.

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