Centenarian microbiome signature

Several studies of extreme longevity — notably the Italian group led by Biagi and Franceschi analysing semi-supercentenarians (105–109 years) and Sato and colleagues in Japanese centenarians — have identified microbiota features that distinguish long-lived individuals from healthy younger or elderly controls. Consistent observations include maintenance of relatively high alpha diversity into extreme old age, enrichment of Christensenellaceae and Akkermansia muciniphila, and a distinctive secondary bile acid profile characterised by elevated concentrations of isoallo-lithocholic acid (isoallo-LCA) produced by Odoribacteraceae family members, which potently induces regulatory T cells and may attenuate systemic inflammation. Whether these signatures are causal contributors to longevity, passenger effects of specific diets or genetics in long-lived populations, or results of survivor bias — those who reach 100+ have presumably already escaped the diseases that kill others earlier — cannot be determined from cross-sectional data. The findings are intriguing and point toward bile-acid–microbiota crosstalk and immune regulation as longevity-associated pathways, but should not yet be interpreted as actionable targets for the general population.