The human gut microbiome refers to the community of microorganisms that live in the gastrointestinal tract. These microorganisms, including bacteria, viruses, fungi, and protozoa, play a crucial role in maintaining the health and well-being of their host. The gut microbiome is considered to be a separate organ system within the body. It has a diverse array of functions, including breaking down complex carbohydrates and fibres, synthesizing vitamins and amino acids, modulating the immune system, and regulating the gut-brain axis.