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Microbiome

Does leaving foraging change the gut microbiome?

Jha AR, Davenport ER, Gautam Y, et al. · PLoS biology · 2018

Open access · cc by · source: Europe PMC

Among 54 Himalayan people, gut microbiomes tracked farming history: Chepang foragers looked most traditional, Tharu farmers closer to Americans, and recently transitioned Raute/Raji sat in between.

Study at a glance

Design
Cross-sectional — Stool 16S comparison of four Himalayan groups along a foraging-to-farming gradient plus 10 European-descent Americans
N
N=54 · 54 Himalayan participants (Chepang 14, Raji 9, Raute 11, Tharu 20); plus 10 Americans (N=64 in some genus analyses)
Population
Rural Himalayan Chepang, Raji, Raute, and Tharu communities compared with Americans of European descent
Outcome
Gut bacterial community composition and how agricultural dependence tracks divergence from a foraging microbiome

Structured fields used in claim comparison tables when every cited study has a complete layer.

Key findings

Lifestyle differences correlated strongly with microbial variation. All four Himalayan groups differed from Americans. Chepang had forager-associated taxa; farming groups were more American-like. Raute/Raji were intermediate, so divergence can happen in one generation.

Methodology

Collected stool from Chepang (still foraging-like), Raute and Raji (farming 30–40 years), Tharu (farming 250–300 years), plus 10 Americans, then related diet/environment to 16S community composition.

Limitations

Cross-sectional stool snapshots cannot prove farming caused the shift, and N is modest; genetics, geography, and unmeasured diet still confound.

How this study connects

Role on claims

Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.

  • SupportsMicrobiomeconcept

    Himalayan gut communities tracked farming history, with foragers most distinct from Americans and recent farmers in between.

    In 54 Himalayan people plus US comparators, stool 16S composition tracked agricultural dependence: Chepang foragers retained forager-associated taxa, Tharu farmers (centuries of agriculture) looked more American-like, and Raute/Raji (farming 30–40 years) sat in between—showing community divergence can appear within a generation of lifestyle change.

    Evidence for the claim as stated.

  • QualifiesMicrobiomeconcept

    Non-viable probiotic vesicles can still change experimental colitis in mice.

    Oral outer-membrane vesicles from E. coli Nissle 1917 reduced DSS colitis severity in mice (less weight loss/DAI and oedema, better histology), cut IL-1β/TNF-α/IL-17 mRNA, raised IL-10, and restored TFF-3, without reversing ZO-1 downregulation.

    Scope note — mouse DSS pretreatment with OMVs ≠ human Himalayan lifestyle microbiome geography

    Limits the claim's scope: a different population, assay, or outcome.

  • SupportsMicrobiomeconcept

    A Himalayan lifestyle-gradient community shift and mouse OMV rescue of DSS colitis both involve gut microbes, but they do not test the same host, exposure, or outcome as cancer MR or pediatric T1D timing studies.

    Evidence for the claim as stated.

Open questions

Tensions this paper is part of

From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.

History

When this study was placed

Dated entries from the concept change log — when this paper was added or removed as support, challenge, or qualifier on a claim.

  1. 2026-09-17

    Placed as supporting evidence on Microbiome

    In 54 Himalayan people plus US comparators, stool 16S composition tracked agricultural dependence: Chepang foragers retained forager-associated taxa, Tharu farmers (centuries of agriculture) looked more American-like, and Raute/Raji (farming 30–40 years) sat in between—showing community divergence can appear within a generation of lifestyle change.

  2. 2026-09-17

    Placed as a scope qualifier on Microbiome

    Oral outer-membrane vesicles from E. coli Nissle 1917 reduced DSS colitis severity in mice (less weight loss/DAI and oedema, better histology), cut IL-1β/TNF-α/IL-17 mRNA, raised IL-10, and restored TFF-3, without reversing ZO-1 downregulation.

  3. 2026-09-17

    Placed as supporting evidence on Microbiome

    A Himalayan lifestyle-gradient community shift and mouse OMV rescue of DSS colitis both involve gut microbes, but they do not test the same host, exposure, or outcome as cancer MR or pediatric T1D timing studies.

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