A microbiota is found in different parts of the body: skin, digestive tract, respiratory system, urogenital system, etc.

“Intestinal flora” is the old term commonly used to define the intestinal microbiota. The two terms mean the same thing.

An ecosystem is a dynamic collection of living organisms (plants, animals and microorganisms) that interact with each other and the environment (soil, climate, water, light, etc.) in which they live.

The intestinal microbiota has many functions: it plays a role in the host’s metabolism (participating in food assimilation), a barrier role (shielding against pathogens), a defense role (stimulating the immune system) and a maintenance role (maintaining the intestinal mucosa, for example). It is at the heart of interactions with various organs, and, among other things, is involved in the transmission of information along a gut-brain axis, which is where the name “second brain” comes from.

The intestinal microbiota is formed at birth, probably even before, through placental exchanges between the mother and the fetus. The external environment and its microorganisms as well as the diet (breast milk, food) also participate in its development.

Various microorganisms, including some species of bacteria, compose the intestinal microbiota. There are dominant species, rarer species and transient species circulating throughout the digestive tract. The colon is populated by nearly 10 000 billion bacteria, that is to say as many as the number of cells in the human body.

Currently, the microbiota is analyzed primarily by the use of identification techniques based mainly on gene (DNA) study of the microorganisms (metagenomics) that populate the intestine.

The intestinal microbiota will evolve over your lifetime and be influenced by various environmental factors. It is formed over a period of years, from birth to age three. Then it continues to diversify to become stabilized in adulthood. Finally, as the years go by, the intestinal flora decreases in the elderly. Some events can also change the microbiota, such as taking medications (antibiotics, for example), infections, a change of environment, illness, stress, etc.

Each individual has a unique microbiota. We call it a “signature”. Only a small fraction of species are widely shared in the human population: around 60 bacterial species are carried by 50% of individuals in the same geographic area.

The microbiota is the name given to the collection of microorganisms (primarily bacteria, viruses, fungi, etc.) that colonize specific places in the body. These microorganisms live in harmony with the body and interact in order for it to function smoothly.