Bile acid metabolism and signaling in human and animal health: A One Health perspective

Abstract The One Health concept emphasizes the interdependence of human, animal, and ecosystem health. Against this broad backdrop, bile acids (BAs), as central products of host‐microbiota co‐metabolism, act far beyond their classical role in lipid emulsification. This review systematically summarizes BA biosynthesis, enterohepatic circulation, and gut microbiota‐mediated metabolic modification. We highlight how gut microbiota‐derived secondary BAs and farnesoid X receptor and Takeda G protein‐coupled receptor 5‐mediated BA signaling together shape BA homeostasis, glucose and lipid metabolism, intestinal barrier integrity, and immune homeostasis. We further discuss how population diversity, circadian rhythm, diet, behavior, environmental exposure, and surgical interventions dynamically shape systemic BA profiles. Finally, from a One Health perspective, we highlight the translational potential of BA‐targeted strategies in hepatobiliary diseases, metabolic disorders, neurodegenerative and retinal degenerative diseases, and intestinal infections, as well as their value in animal production as non‐antibiotic nutritional regulators. By improving animal health and reducing excessive drug use, residues, and risks of antimicrobial resistance at the source, BA‐based precision nutrition may contribute to food safety and ecosystem health. Overall, this review positions BAs as key molecular hubs in One Health, linking host metabolism, gut microbiota, immune regulation, and the integrated health of humans, animals, and ecosystems.