The Gut Microbiome–Human Body Symbiosis: Relevance of the Ubiquitous Microbial Community on Health and Development

Part 1

Abstract

There appears to be a collaborative nexus between the human body and its resident microbes. Research shows strong associations between this parallel universe of microorganisms and our overall health, immunity, and behavior. The human microbiome consists of microbes that flourish in different parts of the body. Our gut with all its projections spans nearly 7 kilometers in length and contains the largest number of microorganisms within the human body. An imbalance in the gut microbiome is strongly associated with allergies, metabolic diseases (eg, diabetes, obesity), neurological conditions (eg, depression, autism), respiratory diseases, liver diseases, and cancer. The development of the gut microbiome is a dynamic process that begins either during gestation or at birth and continuously evolves with human growth into adulthood. The gut microbiome is part of an intricate metabolic and signaling network in the human body. It communicates through biochemical pathways or axes with the skin, brain, lungs, kidneys, breast, and liver. A key motivation behind gut microbiome research is to confirm the cause-and-effect role of the gut microbiota on host health homeostasis. Today, gut microbiome research is generating excitement due to its potential to prevent and treat several interrelated health conditions. Conclusive evidence of the role played by the gut microbiome on human health will furnish new avenues of treatment and better insights into the influence of diet, environment, antibiotics, and genetics on the body. This article, the first of a two-part review, will discuss the relevance of the gut microbiome and its prominent constituents, the developmental trajectory of the gut microbiome from infancy to adulthood and its mutualistic relationship with the human host.