Intestinal Microbiota: First Barrier Against Gut-Affecting Pathogens

Abstract

The complex microbial community of the gastrointestinal tract (GIT) plays an important role in GIT health and in whole body wellbeing by aiding digestion, producing nutrients, protecting against pathogens and in the maturation of the host immune system. A balanced intestinal microbiota and balanced microbe-microbe-host relationships is essential for the performance of all physiological, biochemical and enzymatic machinery in the GIT. Dietary nutrients are converted into metabolites, such as short-chain fatty acids (SCFAs) by the GIT microbiota that serve as biologically active molecules with regulatory functions in the host. When the intestinal microbiota gets unbalanced (dysbiosis) changes to this population can have major consequences. Probiotics may restore the balance of the composition of the GIT microbiota. Prebiotics can modulate the GIT microbiota inducing the growth of probiotic bacteria and can additionally produce beneficial effects on the host. Although there has been a great advance on the knowledge on the composition of the human gut microbiota, still more studies are needed to clarify the interaction of the host and the microbiota, determine the factors that govern host colonization and understand the ecological role of the common and diverse resident microbiota of the human gut.