Variation in gut microbiome diversity and structure across host lifestyles in Thailand

Global comparisons have revealed marked shifts in gut microbiome diversity and composition with industrialization and urbanization. Whether such changes also arise at finer geographical scales, among neighboring populations adopting different lifestyles, remains largely unexplored. In this study, we characterized the gut microbiomes of Thai populations with distinct lifestyles: urban residents from Bangkok, farmers from Tak province, and foragers from Phatthalung province. Our results reveal that microbiomes of all populations are primarily dominated by the families Prevotellaceae, Bacteroidaceae, and Lachnospiraceae, yet their specific abundances differ between populations. -diversity, particularly Faith's phylogenetic diversity, showed a descending trend from the rural to urban populations. Despite these differences, results suggested that most highly prevalent microbial genera were shared among all groups, suggesting the existence of a consistent core microbiome within the Thai population, despite differing lifestyles. Further, association analysis shows that overall population-wide lifestyle was significantly associated with microbial community structure, explaining 0.5-4% of the variation depending on the {beta}-diversity metrics. Linking dietary habits and other lifestyle factors to genus abundance revealed population-specific microbiome-lifestyle associations, indicating that baseline microbial community composition determines microbiome variability in response to environmental changes. Overall, our study expands the scope of lifestyle-microbiome research and identifies associations between lifestyle and microbial features, underscoring the influence of lifestyle factors and baseline microbiomes on microbial compositional adaptation.