Impact of diet on human gut microbiome and disease risk

The gut microbiome of humans comprises a diverse group of trillions of microorganisms including symbiotic organisms, opportunistic pathogens and commensal organisms. This microbiota plays a major role in digesting food; it also helps with absorbing and synthesizing some nutrients and releases their metabolites, which may deliver a variety of growth-promoting and growth-inhibiting factors that influence human health either directly or indirectly. The balance between microbial species, especially those responsible for the fermentation of different substrates within the microbial community, which are in the majority, depends on daily diet. Therefore, an unbalanced diet may lead to the progression and development of human diseases. These include metabolic and inflammatory disorders, cancer and depression, as well as infant health and longevity. We provide an overview of the effect of diet on the human microbiome and assess the related risk of disease development. •The gut microbiome of humans comprises a diverse group of trillions of microorganisms.•The gut microbiome may be considered to be an organ among other human organs that plays a role in human metabolism.•Microbes fall into one of three major groups: symbiotic, commensal or pathogenic.•Daily diet plays a major role in gut microbiome, ensuring microbial diversity and microbial function for the regulation human health.•An unbalanced diet may cause serious disease as a result of a change in microbial gut diversity.