Gut Microbial Function and Immune Aging: An Evidence-Graded Framework Linking Microbial Metabolites to Healthspan and Age-Related Disease.
This narrative review examines how the metabolic output of the intestinal microbiota, rather than its taxonomic composition alone, relates to immune aging and to clinically meaningful geroscience outcomes. We organise the evidence around four questions: which microbial features are reproducibly associated with older ag...