The intestinal flora, also called intestinal microflora or intestinal microbiota, is a set of microorganisms that live in the intestines. Non-pathogenic, these microorganisms play an essential role in the body’s digestion and defense. As such, an imbalance of the intestinal flora can have harmful effects.

What is the intestinal flora or gut microbiota?

The intestinal flora, also called the intestinal microbiota, represents a set of microorganisms present in the intestines. These microorganisms are said to be commensal, that is to say they live in symbiosis with the human body. They are non-pathogenic and contribute to the proper functioning of the body.

Quelle est la composition du intestinal microbiote?

The intestinal flora was formerly called intestinal bacterial flora because studies suggested that it consisted solely of bacteria. Thanks to scientific advances, it is now recognized that the intestinal flora actually consists of many microorganisms including:

• different bacterial strains ;
• viruses ;
• yeasts ;
• Mushroom ;
• protozoa.

The function of the intestinal microbiota in transit

Several studies have confirmed the essential role of the intestinal flora in digestive transit. An imbalance in the intestinal microbiota could be the cause of digestive disorders.

The role of intestinal flora in digestion

The intestinal flora contributes to the digestion of ingested food, by participating in particular in:

• the degradation of certain food residues including certain vegetable fibers;
• hydrolysis of dietary lipids ;
• the breakdown of certain proteins ;
• nutrient assimilation ;
• the synthesis of certain vitamins.

The importance of the intestinal flora for the defense of the organism

The intestinal microbiota participates in the body’s immune defense. The microorganisms of the intestinal flora act in particular for:

• prevent the installation of certain pathogens ;
• limit infectious development ;
• boost the immune system.

Other potential roles under study for the intestinal flora

Several studies show that there is also an interaction between the brain and the intestinal microbiota. An imbalance of the intestinal flora could in particular affect the information transmitted to the central nervous system.

What is dysbiosis

Dysbiosis corresponds to a intestinal flora imbalance. This can be reflected in particular by:

• an imbalance between certain microorganisms, in particular between pro-inflammatory agents and anti-inflammatory agents;
• the predominance of certain microorganisms such as enterobacteria or fusobacteria;
• the depletion or absence of certain microorganisms such as bacteria Faecalibacterium prausnitzii.

What is the risk of complications?

Research on the intestinal flora shows that dysbiosis could be involved in the development of certain diseases including:

• chronic inflammatory bowel disease (IBD), such as Crohn’s disease or ulcerative colitis, which are characterized by an inadequate immune response within the intestine;
• metabolic disorders, such as type 2 diabetes and obesity, which affect how well the body works;
• le colorectal cancer, when a tumor develops in the colon;
• certain neurological diseases, due to the link between the gut microbiota and the brain.

What are the risk factors for dysbiosis?

An imbalance of the intestinal flora can be favored by certain factors such as:

• a poor diet ;
• taking certain medications;
• the stress.

Preventive measures for the maintenance of the intestinal flora

It is possible to prevent dysbiosis by limiting the risk factors. For this, it is necessary to adopt a healthy and balanced diet, to practice regular physical activity and to limit the factors of stress and anxiety.

Nutritional supplementation to restore the intestinal flora

The use of food supplements is often recommended to naturally restore the intestinal flora. The balance of the intestinal microbiota can be preserved thanks to:

• probiotics, which are living microorganisms beneficial for the balance of the intestinal flora;
• prebiotics, which are substances that promote the development and functioning of bacteria in the intestinal flora;
• symbiotics, which are a mixture of prebiotics and probiotics.

Faecal microbial transplantation

In the most serious cases, a transplantation of certain microorganisms of the intestinal flora could be considered.

Preliminary examinations: evaluation of certain markers

The analysis of the intestinal flora is often motivated by doubts during a physical examination. In the event of suspicion during this examination, the healthcare professional may request additional analyzes. The measurement of certain biological markers can in particular be carried out. The presence of certain specific inflammatory markers can for example be sought to confirm the development of chronic inflammatory bowel disease (IBD).

Coproculture: examination of the flora in the stool

The coproculture est a bacteriological examination of the stool. Although this analysis does not give the exact composition of the intestinal flora, the stool culture gives essential information to guide or confirm a diagnosis.

This bacteriological analysis can be associated with a exam parasitologique des selles (EPS) to check for the presence of parasites.

Endosco? Pie digestive: invasive analysis of the intestinal flora

Digestive endoscopy, also called digestive fibroscopy, can:

• visualize the inside of the digestive tract to identify the presence of lesions;
• perform a biopsy to analyze the tissues and the composition of the intestinal flora.

Progress towards a less invasive analysis technique?

If endoscopy is an invasive analysis technique, it may soon be possible to perform an analysis of the intestinal flora in the same way as a blood test. This could be made possible through the use of DNA microarrays.

The richness of the intestinal flora

According to the researchers, there are between a trillion and a hundred thousand billion microorganisms in the intestinal flora. They are thus two to ten times more numerous than all the cells present in the human body.

A complex and unique gut microbiota

The gut microbiota is a complex and unique ecosystem. With nearly 200 different species of microorganisms, its exact composition depends on each individual. The intestinal flora is created from birth and evolves over the years depending on various factors including genetics, diet and the environment.

Promising prospects

The work carried out on the intestinal flora opens up promising therapeutic prospects. A thorough analysis of the intestinal flora could lead to the development of new treatments, which could be personalized according to the profile of the intestinal flora of each person.