Soil influences on rural versus urban human gut microbiota and implications on cardio-metabolic health: a comparative...

Humans are exposed to surrounding soil environment and this exposure has reduced with growing urbanisation. Limited evidence exists on how rural and urban soils shape human gut microbiome and related functions. Here, we performed metagenomic analysis, functional prediction, gene ontology using QIIME2, PICRUSt, and DAVID by taking human stool and soil samples (n = 20) from rural and urban settings to characterise gut microbiota and their resemblance to their respective soil microbiota and its functional implications. Our findings demonstrated that soil environment affects gut microbial diversity and abundance of its immediate human inhabitants in both groups and observed shared microbial and functional properties in rural- and urban-guts characteristic of their respective soil microbiota. In rural-group, phylum Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, class Actinobacteria were major overlapping features, while in the urban-counterpart phylum Proteobacteria, Firmicutes, class Gammaproteobacteria were observed. We also demonstrated implication of this differential composition on human health in both settings, and observed enrichment of cytokines like IL-12, IFN-ϒ, and oxidative phosphorylation pathway in rural group vital to metabolic homeostasis. While enrichment of response to toxic substances, methane metabolism, and potentially low levels of alanine in the urban counterpart, linked to impaired immune response and metabolism, suggests urban group may be prone to the cardio-metabolic disease risk. These observations were consistent with other findings emphasising rural groups have healthy sets of microbiome compared to their urban counterpart. In conclusion, our findings unveil the significance of soil microbiota in evolution and shaping of human gut microbiota, thereby potentially beneficial to human health.

The online version contains supplementary material available at 10.1007/s13205-025-04675-x.