Determinants of the healthy gut microbiome: core features, modifying factors and normal functions.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing existing literature without primary human data or systematic review methodology.
PubMed 41868872 · doi:10.20524/aog.2026.1034
What was done
This review synthesized current literature on the composition, modifying factors (including diet, geography, genetics, and environment), and normal physiological functions of the gut microbiome in healthy individuals across diverse populations.
What was found
The abstract reports no numerical values. Qualitatively, it reports that healthy gut communities are dominated by Firmicutes and Bacteroidetes, with contributions from Actinobacteria and Proteobacteria. Notable variations include higher Prevotella abundance in populations consuming fiber-rich Eastern diets compared to higher Bacteroides abundance in Western cohorts. Reported functional roles include short-chain fatty acid production from fiber fermentation, immune regulation, gut-brain axis modulation, intestinal barrier maintenance, and support for cardiovascular and hepatic functions.
Why it matters
It highlights that a normal microbiome should be evaluated as a resilient, multifunctional organ system rather than a fixed composition of specific bacterial taxa.
Limits
The abstract describes a narrative review without primary data, systematic search criteria, or pooled statistical metrics. Broad variability across host geography, lifestyle, and anatomical sampling sites complicates establishing universal normative benchmarks.
Cited by
- supports The normal human gut microbiome is predominantly composed of four main bacterial groups or phyla.