All about the gut microbiota

Food - Posted onTuesday 21 September 2021

Gone are the days when bacteria were considered the number one public enemy. For years, science has been interested in the role of the bacteria, fungi and other viruses that make up our intestinal flora, now well-known under the name ‘intestinal microbiota’.

Discovering the gut microbiota

Gut microbiota is a hot topic today because of its multiple links with various reactions in our body.

What does it represent?

Our intestine is home to 100,000 billion bacteria, viruses and fungi, i.e. 10 times more than the total number of cells in our entire body!
All of these bacteria make up the famous intestinal microbiota, which is considered an organ in its own right.

When did we first come into contact with the microbiota?

Our relationship with microbiota begins very early, long before we are born. Recent studies have suggested the presence of bacteria in the amniotic fluid. But it is after our birth, and particularly after a vaginal delivery that, in just a few hours, our quasi-sterile space is transformed into an environment populated by thousands of bacteria: a decisive stage in the constitution of our intestinal microbiota.

From the end of pregnancy until around the age of three, the intestinal microbiota establish under the influence of various factors such as genetics, the type of diet (a breast-fed child will have more bacteria of the Lactobacillus type, known to have a beneficial impact on health) and even the mode of delivery.

Each person therefore has a unique microbiota composition, like a fingerprint.

What are these bacteria?

Certain families of bacteria are constantly present in our intestine: we speak of dominant and sub-dominant microbiota. The transient microbiota, on the other hand, play a transitory role.

  • The dominant microbiota span three families of bacteria, namely Firmicutes, Bacteroidetes and Actinobacteria, with the first two representing 90% of all intestinal microbiota.
  • The sub-dominant microbiota is composed of different bacteria, of which the best known is Escherichia coli.
  • The passage microbiota is mainly composed of bacteria of food origin.

The functions of the gut microbiota on our health

In 2008, the MétaHIT study (INRA) revealed the richness of our intestinal flora; it was possible to isolate 3.3 million genes, belonging to more than 1,000 different species, which represents, for a given individual, 540,000 genes for 160 species on average.

But how can these bacteria play a positive role in our health?

A microbiota composition that’s rich in quality and quantity can ensure numerous functions essential to our well-being. They play:

  • A nutritional role, as they help to decompose non-digestible food residues and assimilate nutrients, such as fatty acids.
  • A protective role, thanks to a barrier effect that prevents the multiplication of undesirable bacteria.
  • An energetic role, by participating in the synthesis of certain B and K vitamins that are important for the metabolism of our cells.

Did you know?

According to the work of French researchers*, the intestinal microbiota (in particular, bacteria such as Enterococcus hirae and Barnesiella intestinihominis) can boost the therapeutic effects of anti-cancer drugs used to treat many cancers.

*Research team from Inserm, the Gustave Roussy Institute, the CNRS, the Pasteur Institute of Lille, and the universities of Paris Sud and Lille

Dysbiosis, a consequence of intestinal imbalances

The intestinal microbiota serve the body by protecting it and reinforcing its defences. However, when our intestinal flora is altered, the microbiota can become imbalanced. This imbalance, due to the predominance of certain harmful bacteria and the reduction of other favourable bacterial species, can then lead to dysbiosis, which is the cause of certain inflammatory diseases:

  • Constipation, diarrhoea, chronic intestinal diseases (e.g. Crohn’s disease)
  • Irritable bowel syndrome (bloating, digestive problems, pain, etc.)
  • Food intolerance.

Microbiota and stress

What if stress doesn’t come from your brain but rather from your intestine?

With its 200 million neurons and its autonomic nervous system, the intestine is often considered our second brain. We can easily understand the pathway between the brain and the gut (when, for example, excessive stress causes nausea), but what is new is that we can better understand the reverse pathway. Recent research has shown that the intestinal microbiota are involved in managing our emotions and even influences our personality!

In stressed or depressed patients, microbiota undergo numerous changes, with a decrease in certain bacteria such as the Bacteroidetes.

Microbiota and obesity

What if intestinal microbiota and obesity were closely linked? This is what many studies have tried to show by analysing the different intestinal bacteria present in healthy and obese people. According to the European MetaHIT project, obese people have a lower bacterial diversity than healthy people. This lack of diversity is not without consequences, such as metabolic syndrome with vascular disorders or type II diabetes.

Low bacterial diversity, but also the significant absence of certain bacteria that are beneficial to our health, are at the origin of certain pathologies. Akkermansia muciniphila is currently under the spotlight: patients with a higher level of this bacterium have a healthy metabolic profile: lower blood sugar levels, insulin resistance, etc. This current star could be used to design new treatments for obesity!

Think preventive health with the Juvenalis Intestinal Microbiota Assessment

Do you suffer from irritable bowel syndrome, food intolerances or chronic inflammatory diseases?

It may be interesting to carry out a mapping of your intestinal microbiota in order to find out if you have a dysbiosis.

This comprehensive mapping will identify and quantify your gut bacteria. It can also potentially identify the presence of pathogens in your microbiota.

This information will allow you to implement solutions to try to rebalance your microbiota and reduce your symptoms.