**1. Introduction**

Microbes inhabit almost all human body parts and play a critical role in human health and disease. Research has increasingly focused on the diverse microbial communities that interact with the host to influence disease processes as modern microbiology and next-generation sequencing technologies have evolved. The term 'microbiome' refers to the complex blend of microorganisms such as bacteria, bacteriophage, viruses, fungi, single-celled animals and their genes as well as metabolites. Colonizing different body niches which contribute in big ways to human health and wellness. As microbial communities, also known as the microbiota, microorganisms, or microbes, coexist and interact with one another and with the surrounding environment. The microbial communities within our body are highly personalized and considered as unique to each individual as

their fingerprints [1] also unique to each body sites [2]. This can also be referred to as the metagenome of the microbiota. The word "microbiome" was coined by Joshua Lederberg, who was the first to use it to "symbolize the ecological community of commensal, symbiotic, and pathogenic microorganisms that literally occupy human body space and have been largely overlooked as health and disease determinants" [3]. Over time, the term microbiome has evolved not only to refer microbiota, but also to the genetic information and the genomes of the microorganisms themselves. It is now well known that the microbiome interacts with its host and also involved in basic human biological processes, modulating the metabolic phenotype in the bioconversion of nutrients and detoxification, influencing innate immunity and protecting against microbial infections. Microbiota boosts the immune system, breaks down potentially hazardous dietary molecules, and synthesizes vitamins like vitamin B12, thiamine, riboflavin, and vitamin K, which is required for blood coagulation [4]. Microbiome is home to trillions of symbiotic microorganisms in which some of these are useful, and some are harmful and it supports many physiological functions, helps in maintaining the integrity of our gut lining, and protects us from disease and infection. Therefore, a perfect and sensitive balanced interaction of microbes with the host is required for a healthy body. The microbiota has many more metabolic genes than the human genome and provides unique enzymes and biochemical pathways to humans [5]. Furthermore, many of the positive metabolic macrobiotic activities for the host are engaged in either food acquisition or xenobiotic processing, such as the metabolism of undigested carbohydrates and vitamin production [6].

Second, through competitive exclusion and the generation of antimicrobial compounds, the human microbiota acts as a physical barrier, protecting its host from invading pathogens [7].

Understanding how microbial metabolites influence the health or disease status would have a significant impact on treating diet related diseases [8]. Microbes that cause disease build up over time, affecting gene activity and metabolic processes and causing an incorrect immune response to substances and tissues that are normally present in the body. Autoimmune diseases tend to be passed down through generations via microbiome inheritance rather than DNA transmission [9]. Recent studies revealed that the associated microbes stimulates the normal development of the humoral and cellular mucosal immune systems and the signals and metabolites of microorganisms can be sensed by the hematopoietic and non-hematopoietic cells of the innate immune system and translated into physiological responses [10]. Often, reduction in microbial diversity and outgrowth of specific species can induce negative effects like inflammation or infection [11]. However, most of the microbial taxa and species of the human microbiome are still unknown. Without revealing the identity of these microbes as a first step, we cannot appreciate their role in human health and diseases [12].

There are plenty of projects trying to decode the human genome by sequencing all human genes. In a similar way, the microbiome has been subject to intensive efforts to unravel all its genetic information. Advances in omics-based techniques have contributed to a better knowledge of the microbiome and the many factors that influence its microbial composition. Understanding the entire spectrum of the "microbiome's" role in health and disease is still in its infancy. Our bacterial flora clearly plays a far larger influence in systemic disorders than previously thought [13]. High throughput sequencing reveals the amazing complexity and extent of the microbial communities that reside within or upon us therefore various computational approaches are available to analyze the microbiota on an unprecedented scale [14]. Recent scientific advances in genetics mean that humans know a lot more about the microbes in the body. Researchers from across the globe are investigating how changes in the

#### *Microbiome - The Power House of Health and Disease DOI: http://dx.doi.org/10.5772/intechopen.106026*

microbiome are linked to, or perhaps cause, illnesses, as well as developing new therapeutic ways to modify the microbiome to cure disease and restore and support health. In addition, microbiome research is gaining tremendous interest as documented by the explosion in publications with more than 20,000 articles published in 2020 alone. The rapid development of new molecular tools such as transcriptomics, metagenomics, and metabolomics has aided in the recent advancement of microbiome results linked to humans. These fast evolving recent technologies are enhancing our ability to comprehend the human body and the microbiome that affects health. Researchers need to conclude with future directions and how to convert the basic science into translational medicine and development of innovative microbiome-based therapy.
