The gastrointestinal microbiome is thought to influence health and disease throughout life. Understanding the factors that shape microbial diversity and composition during critical developmental periods could present valuable opportunities for intervention. A new study examined associations between early caregiving environments and the composition of the infant gut microbiome in the first 6 months of life.
Methods
Researchers analyzed data from 60 infants participating in the Pregnancy Experiences and Infant Development Study (PEIDS) in Southern California. They collected stool samples at 2 weeks, 2 months, 6 months, and 12 months of age, yielding a total of 84 samples across all time points.
Mothers were interviewed between 1 and 3 weeks postpartum about their infant's social environment, including skin-to-skin contact, physical contact, and caregiving practices. The V3-V4 region of the 16S rRNA gene was sequenced to characterize the gut microbiome.
The study published in the American Journal of Physical Anthropology examined associations between caregiving factors and alpha diversity, beta diversity, and differential abundance of bacterial genera. Analyses were adjusted for infant sex, breastfeeding status, and delivery mode.
Results
Time infants spent in physical contact with caregivers explained 10% of the variation in beta diversity of their gut microbiome at 2 weeks of age. Additionally, the number of caregivers an infant was exposed to accounted for 9% of the variation in beta diversity at 2 weeks. A diverse range of caregivers can significantly influence the microbial community structure.
The number of individuals in physical contact with the infant at birth was found to explain 11% of the variation in beta diversity observed at 6 months of age, suggesting initial physical interactions at birth have a long-lasting impact on the infant gut microbiome development.
The study highlighted the positive association between skin-to-skin contact on day of birth and the abundance of eight specific genera of gut bacteria.
Study Limitations
The authors noted several limitations, including:
- Relatively small sample size
- Reliance on maternal reports of caregiving practices
- Inability to determine species-level taxonomic identification due to the use of 16S rRNA sequencing
- Lack of direct observational data on infant social interactions and caregiving contexts
- Absence of caregiver gut microbiome characterization
The researchers suggested future research could benefit from direct observational data and characterization of caregiver gut microbiomes.
Disclosures were not made available at time of publishing.
