The gastrointestinal (GI) tract serves as a dynamic chemosensory interface that integrates signals from dietary phytochemicals and microbiota-derived metabolites to regulate host physiology. Beyond digestion and absorption, specialized epithelial and enteroendocrine cells detect luminal compounds via receptors such as taste (sweet, bitter), olfactory, and transient receptor potential (TRP) channels. Phytochemicals - including terpenoids, glycosides, flavonoids, and volatile compounds - activate these receptors to modulate gut hormone secretion, appetite, energy balance, and immune function. Similarly, microbiota-derived metabolites such as short-chain fatty acids, bile acids, and tryptophan derivatives act through G protein-coupled and nuclear receptors to coordinate metabolic, immune, and neuroendocrine processes. Together, these receptor-mediated pathways form a complex communication network linking diet, microbes, and host signaling systems, influencing metabolic health and disease. Future research integrating multi-omics and advanced imaging is expected to clarify these molecular interactions and support the development of precision nutrition strategies targeting gut chemosensory systems for the prevention and treatment of obesity, diabetes, and related disorders.
