What is the microbiota?
The microbiota represents all the living microorganisms that evolve in a specific environment. Among all these species (bacteria, viruses, fungi and yeasts), bacteria make up a large population that live permanently with humans. Thus, from the moment we are born we live in symbiosis with billions of bacteria that colonize our organism until we die. There are several microbiotes associated with the human body among which we can mention the microbiota of the skin, the mouth, the bronchial tubes, the vagina, but also the intestinal microbiota which is the richest but also the most diversified (especially at the level of the colon).
Organisms essential to our life and good health
For millions of years, bacteria have been able to evolve and adapt in such a way that they have become indispensable to the human body. Thus these organisms that until recently were seen as harmful to humans have emerged as essential organisms for our life and good health. Over the last twenty years, thanks to the development of genetic and genomic approaches, in particular with the analysis of the gene coding for 16S rRNA (called metagenomics), our knowledge of bacteria has continued to grow. This interdependent relationship between humans and bacteria is the result of a harmonious cohabitation that contributes to many physiological processes in its host (Hooper and Macpherson, 2010) with the host in turn providing a nutrient-rich niche in which bacteria can thrive. Thus, bacteria assist in the digestion of many food substances (digestive efficiency) but also in the synthesis of vitamins and essential amino acids (Qin et al., 2010) and in the education/maturation of our immune system. In addition, they produce bactericidal substances that help limit the invasion by pathogenic bacteria (Neish, 2009). Nevertheless, this cohabitation is only harmonious as long as a balance is maintained. Indeed, although many bacteria are beneficial to humans, some can be harmful and others can become deleterious in the event of imbalances, so temporary disturbances, infections, allergies or more serious pathologies can be associated with disturbances of the microbiota. Numerous studies have observed imbalances associated with numerous pathologies such as metabolic diseases (e.g. obesity, type 2 diabetes), digestive diseases (e.g. IBS, IBD, Crohn’s disease, ulcerative colitis), cancers (carcinogenesis and anti-cancer therapies), autoimmune diseases (e.g. cancer, cancer, cancer, etc.) and other diseases: lupus, type 1 diabetes), neurological diseases (e.g. Parkinson’s, autism, chronic fatigue syndrome, schizophrenia), but also cardiovascular diseases (e.g. high blood pressure, atherosclerosis and heart failure).
Today, the microbiota is revolutionizing science, medicine and nutrition and constitutes a human health indicator with a place of choice in the patient’s medical history for the diagnosis and prognosis of pathologies but also as an indicator of tolerance and response to treatments.
Hooper, L. V., & Macpherson, A. J. (2010). Immune adaptations that maintain homeostasis with the intestinal microbiota. Nature Reviews Immunology, 10(3), 159.
Qin, J., Li, R., Raes, J., Arumugam, M., Burgdorf, K. S., Manichanh, C., … & Mende, D. R. (2010). A human gut microbial gene catalogue established by metagenomic sequencing. nature, 464(7285), 59.
Neish, A. S. (2009). Microbes in gastrointestinal health and disease. Gastroenterology, 136(1), 65-80.