Targeting the human gut microbiome: a comparative review of probiotics, prebiotics, synbiotics, and postbiotics

The gut microbiome acts as a dynamic microbial organ essential for digestion, immune maturation, and metabolic homeostasis. Dysbiosis, characterized by a loss of beneficial microbes and an overgrowth of potential pathogens, is a critical factor in the pathogenesis of gastrointestinal disorders, metabolic diseases, and other systemic conditions. The gut microbiome engages in continuous bidirectional communication with distant organs, including the oral cavity, lungs, skin, and urinary tract, via specific axes (e.g., gut-oral, gut-lung, gut-skin), thereby exerting widespread influence on host physiology. Probiotics, prebiotics, synbiotics, and postbiotics represent complementary strategies to counteract dysbiosis and reestablish gut ecological integrity, ranging from introducing live beneficial bacteria to utilizing inactivated microbial cells and their bioactive metabolites. Enhancing the translational potential of these interventions requires deeper mechanistic insights and robust clinical validation.