In the sarcopenia group, SCFAs formed two major clusters: (1) branched-chain SCFAs (isobutyric, 2-methylbutanoic, 3-methylbutanoic, and 4-methylpentanoic acids), which showed predominantly weak or negative correlations with inflammatory cytokines; (2) straight-chain SCFAs (butyric, propionic, pentanoic, and hexanoic acids), which demonstrated moderate positive correlations with IL-6, IL-10, and IL-18. The gene discussed is IL18; the disease is sarcopenia.