Influence of gut microbiome on the human physiology

Trillions of microbes harbor the gastrointestinal tract and co-exist peacefully with the human host. Microbial diversity and composition among individuals depend upon human age, diet, and environmental factors. The dynamic population of the gut microbiome, majorly consisting of Bacteroidetes and Firmicutes, forms a complex ecological community. The collective metabolic activities and interaction of gut microbiota with the host exert a marked influence on human physiology. The gut microbiota help to perform various functions, such as maintenance of intestinal mucosal integrity, production of anti-microbial peptides, protection against foreign invaders, and immunity development. In addition, they also provide essential nutrients, such as enzymes and vitamins, and also take part in metabolite synthesis, which influences both cognitive and behavioral functions of the human host. Homeostatic equilibrium among gut microorganisms, and between the microbes and intestinal interface of the host allows the maintenance of beneficial microbiota. Any alteration or dysbiosis in gut microbial composition, due to a sedentary lifestyle or intake of an unbalanced diet, plays a crucial role in the development of diseases like systemic inflammation, insulin resistance, auto-immune and metabolic disorders. This review summarizes our current understanding of the gut microbial organization, its importance in the fundamental biological processes and the pathogenesis of various human diseases and infections, and also the prognostic, diagnostic, and therapeutic potential of the gut microbiota.