Prospective associations of tea consumption with skeletal muscle mass and strength: Insights from the gut microbiome and proteomics.

Tea consumption may be associated with skeletal muscle health, but longitudinal evidence based on repeated assessments remains limited. We examined the associations of tea intake and serum biomarkers with repeated skeletal muscle measures and explored whether these associations might be partly explained by multi-omics features. In this prospective cohort, 3408 adults were followed for approximately 12 years. Skeletal muscle mass was measured by dual-energy X-ray absorptiometry, handgrip strength by digital dynamometry, gut microbial taxonomic and functional profiles by shotgun metagenomic sequencing, serum proteins by data-independent acquisition mass spectrometry, and fecal metabolites by targeted UPLC-MS/MS metabolomics. Linear mixed-effects models examined longitudinal associations, and mediation analyses estimated indirect effects. In longitudinal analyses, higher tea consumption frequency was associated with greater appendicular skeletal muscle mass, appendicular skeletal muscle index, and handgrip strength (β: 0.037-0.140; 95% CI: 0.002-0.205). Higher circulating flavan-3-ols showed similar associations with these muscle-related outcomes (β: 0.085-0.174; 95% CI: 0.007-0.254), whereas no significant associations were observed with walking speed. Exploratory multi-omics analyses identified tea-related differences in gut microbial species and functional pathways, fecal metabolites, and circulating proteins, including Gemmiger formicilis, amino acid biosynthesis pathways, fructose 1,6-bisphosphate, VTN, CFI, CNDP1, and ITIH4. Exploratory mediation analyses identified statistical indirect associations involving multi-omics features, with estimated proportions mediated ranging from 4.5% to 19.0%. Overall, higher tea consumption and circulating biomarkers were associated with greater skeletal muscle mass and strength, accompanied by distinct multi-omics features that may provide potential biological links between tea exposure and muscle-related outcomes.