Tribal Gut Microbiomes: Diet Shapes Indian Community Patterns

Why in news?

Background

The National Centre for Cell Science (NCCS) is an autonomous Department of Biotechnology institution in Pune. A tissue-culture facility began in 1986 and became a registered national collection during 1988. Later organisational changes created the present centre.

NCCS conducts cell biology, immunology, genomics and microbial ecology research. It also maintains national cell resources and supports scientific training. The centre now operates within the Biotechnology Research and Innovation Council network.

The human gut contains bacteria, archaea, viruses and other microorganisms. Their genes and metabolic activities collectively form a complex microbiome. Diet, medicines, age, environment and lifestyle can alter its composition.

Most global microbiome datasets overrepresent industrialised populations. Indian tribal communities contain diverse diets and practices that remain poorly sampled. The study appeared in Gut Microbes on 9 July 2026.

How the study was conducted

Researchers recruited seventy-six healthy adults between June and October 2019, with an average age of thirty-four years. Women formed fifty-eight per cent of the sample.

The eight communities represented four biogeographic settings, with Warli participants representing the western coast. Gond and Madia groups represented the northeastern Deccan Plateau.

Kabui, also called Rongmei Naga, represented the northeastern Himalayan hills. Balti, Boto, Brokpa and Purigpa participants represented the northwestern Trans-Himalayas. Each community retained its own identity, history and food traditions.

Participants provided faecal samples, dietary recalls and food-frequency information, while ribosomal gene sequencing compared bacterial groups. Metagenomic sequencing then examined microbial genes and reconstructed genomes.

The institute's ethics committee approved the work, and participants gave consent, although not everyone released all personal metadata. This limitation reduced the team's ability to test age, sex and body-size effects.

Dietary patterns recorded

Rice, turmeric and chilli appeared widely across the participating communities. Plant foods formed most recorded diets during the sampled summer season. Meat or fish occurred about twice weekly on average.

The four Trans-Himalayan groups ate wheat, barley, milk and homemade butter daily. Those foods were uncommon or absent in the other sampled groups. Some communities outside that region regularly consumed traditional fermented beverages.

Dietary questionnaires describe reported patterns rather than controlled feeding. Geography, livestock contact and unmeasured factors changed alongside diet, so researchers could not isolate one cause experimentally.

Main microbial findings

Segatella, Agathobacter and Faecalibacterium occurred across every community, while Segatella copri was especially abundant. Formerly called Prevotella copri, its average relative abundance ranged from twenty-five to forty-seven per cent.

Trans-Himalayan samples showed higher within-sample diversity, with Bifidobacterium present in every participant from that region. It was much less abundant across the other regions.

Several enriched bacteria have previously appeared in milk, fermented dairy or cattle microbiomes. Daily dairy contact might influence human gut communities through diet or environment. The study described this as a plausible explanation, not confirmed transmission.

Indian Bifidobacterium adolescentis strains differed genetically from many industrialised reference strains. Their carbohydrate-active enzymes could process particular milk and plant compounds. Those patterns were consistent with adaptation to dairy and grain-rich diets.

What the genome counts mean

Metagenomic analysis identified five hundred representative genomes across 203 genera. Researchers assembled 220 directly from samples, and fourteen genome groups represented putatively novel bacterial species.

The paper also described about two hundred local microbial strains. A strain is a genetic variant within a species, not another species. Calling all two hundred “new species” would therefore be wrong.

“Putatively novel” is another important qualification. Genome comparison suggests separation from known species, but formal naming requires additional taxonomic work. Some organisms may also require cultivation and detailed biological description.

What the study does not establish

The research captured one period and cannot prove that dairy caused the observed bacterial composition. Longitudinal studies and controlled experiments would be necessary for stronger causal claims.

Seventy-six participants across eight communities provide limited statistical power, while the design measured no future disease outcomes. Greater diversity should not automatically be equated with better health.

Some participants resembled an earlier Californian dataset, suggesting that globalisation might influence these microbiomes. That comparison cannot diagnose industrialisation or personal health in any participant.

Ethics and future research

Microbial samples can reveal diet, medicine exposure and community-specific biological patterns. Research needs consent and fair data governance, with communities receiving meaningful information about uses and findings.

Commercial interest in unique strains could create benefit-sharing questions. Clear agreements should precede patents, products or further transfers. Tribal identity must never become a marketing label for unproven supplements.

Larger repeated studies could distinguish seasonal, dietary and geographic influences. Laboratory work can test functions suggested by genome sequences. Such research may improve understanding without portraying one lifestyle as biologically superior.

Conclusion

The study expands an underrepresented part of global microbiome knowledge. Its strongest result is documented diversity, while causal and health claims require much more evidence.