Distinct trajectories of urbanization shape the human gut microbiome across South Asia.
Microbiome responses to urbanization vary significantly across different South Asian communities, highlighting the importance of community-specific health investigations.
Where it sits
this study against the rest of the selank corpusSummary and findings
This study measured the gut microbiome of 575 adults from ten diverse South Asian communities, comparing ancestral villages and urban centers. It found that microbiome responses to lifestyle transitions are largely community-driven, with significant associations of urbanization markers with increased abundance of disease-linked taxa. No therapeutic claims are made.
Abstract
Human gut microbiomes respond to lifestyle transitions, yet the extent to which these responses are conserved across spatio-cultural contexts remains undercharacterized. We present the South Asian MicroBiome ARray (SAMBAR), a population-scale 16S gut microbiome study of 575 adults from ten geographically and socio-culturally diverse South Asian communities. Each community was sampled in ancestral villages and urban centers, enabling controlled comparisons of geography and lifestyle. Relative to global cohorts, SAMBAR microbiomes occupy a distinct compositional space with stronger correlation to geography and community membership than lifestyle. Microbiome responses to lifestyle transitions are largely community-driven, including the acquisition of wheat- and dairying-associated microbial modules in some communities that may facilitate non-genetic adaptation to lactase nonpersistence. Concurrently, we identify significant associations of urbanization markers with increased abundance of disease-linked taxa, especially <i>Megamonas</i>-correlated with increased blood glucose and lower gut microbiome diversity-which is enriched in SAMBAR over comparative global regions. Overall, microbiome responses to urbanization are heterogeneous even at regional scales, reflecting local culture and geography, and underscoring the need for community-specific investigations of health impacts.
Background
This paper addresses how urbanization impacts the human gut microbiome across different South Asian communities. Prior research has indicated that lifestyle transitions can affect gut microbiomes, but the extent of these changes across diverse cultural contexts is not well characterized. Understanding these variations is crucial for assessing health impacts related to urbanization.
Methods
The study utilized a population-scale 16S gut microbiome analysis involving 575 adults from ten geographically and socio-culturally diverse South Asian communities. Each community was sampled in both ancestral villages and urban centers, allowing for controlled comparisons of geography and lifestyle. The primary outcome measure was the composition of the gut microbiome, with secondary outcomes including associations with urbanization markers.
Results
The study found that microbiomes from South Asian communities occupy a distinct compositional space compared to global cohorts. Urbanization markers were significantly associated with increased abundance of disease-linked taxa, particularly <i>Megamonas</i>, which correlated with increased blood glucose and lower gut microbiome diversity. Specific numeric findings were not reported in the abstract.
Interpretation
The findings suggest that microbiome responses to urbanization are influenced more by community-specific factors than by lifestyle changes alone. While the study identifies significant associations, the clinical relevance of these findings remains unclear, particularly given the lack of robust effect sizes reported. Confounding factors such as cultural practices and dietary habits may limit the conclusions drawn from this research.
Key findings
- 575 adults sampled from ten communities.
- Increased abundance of disease-linked taxa associated with urbanization.
- Microbiome responses to lifestyle transitions are largely community-driven.
- Stronger correlation to geography and community membership than lifestyle.
- Microbiome responses to urbanization are heterogeneous even at regional scales.
Limitations
- Not generalizable due to specific cultural contexts.
- Cross-sectional design limits causal inferences.
- No specific numeric findings reported.
- Potential confounding factors not fully addressed.