The Intestinal Microbiome in Humans: Its Role for a Healthy Life and in the Onset of Diseases

Abstract

The discovery of human microbiota shed a different perspective regarding human homeostasis and immune regulation. Gut microbiota comprises a multitude of microorganisms, its composition being host-specific and evolving throughout the lifetime, being subjected to both endogenous and exogenous factors. This subject gained significant interest after the improvement of metagenomic and metabolomic studies. The gut microbiome displays several roles, such as modulating gut permeability, digestive processes, metabolic pathways, and immune responses. Any dysregulation in the complex symbiosis mechanism between humans and the intestinal microbiome might lead to variable diseases. Environmental factors and diet play a very important role in maintaining a healthy gut microbiota. In this chapter, one aims to discuss the core microbiome of healthy subjects and how different stages of dysbiosis can play a role in the initiation and progression of pathogenic mechanisms leading to several diseases, such as gastrointestinal disorders (irritable bowel syndrome, inflammatory bowel diseases, infections or diarrhea associated with antibiotics, and colon cancer), metabolic disorders, obesity, diabetes, and allergies. We underline the importance of diet and environmental factors in modulating gut microorganism concentrations. We shed light on new possible perspectives regarding the modulation of gut microbiota for improving the health status of the host.