Intestinal microbiota

Intestinal microbiota

Although its role in digestion and transit has been recognised for a long time, the intestinal flora, today called microbiota, never fails to astonish us!

This organ in its own right weighs more than a kilo and is not made up of human calls but rather of 100,000 billion bacteria, which live in our intestines where they find their food. Their many functions, essential for our well-being and health, have recently been discovered: immune system support, metabolism, combating inflammation and allergies…

So let's find out more about the microbiota to better understand its importance, and also its fragility, and learn how to take care of it via a healthy lifestyle and diet.

The intestinal microbiota , what is it?

It is believed to contain about 100 billion bacteria, 10 times the number of our cells, and is composed of a wide bacterial diversity (800 to 1000 different species identified) which are spread throughout the digestive tract with greatest density in the colon.

A microbiota which develops at the same time as we do

From the very moment of birth... Our flora is established at birth via natural routes, mainly from the mother, and in the case of a caesarean section it is influenced by the ambient air. And subsequently through milk (mother's milk or formula), from breathing and the family environment, the "colonisation" continues.

It is through dietary diversification that the composition of the flora increases in terms of both diversity and quantity, stabilising at around the age of 3.

Changes also take place alongside hormonal developments (puberty, pregnancy, menopause). With age its composition appears to become less diverse.

A microbiota that is unique to everyone, like a finger print

It can be observed that 3 main bacterial groups are present in every individual. However, nearly 80% of the dominant microbiota species are unique to the individual. Consequently, every human being hosts their very own set of microbiota.

It should also be noted that the dominant bacteria species are very stable in a healthy adult.

They have a major role in our health and well-being

Role in digestion:

  • The microbiota breaks down various food compounds (fibre, amino acids, etc.), which are fermented, producing gases and primarily fatty acids which act as nutrients for intestinal cells. They draw from them the energy required for their maintenance and renewal. The integrity of the mucosa is thus preserved.

Support for the immune system and our natural defences:

  • Protect the digestive tract against colonisation by pathogenic microbes: it's the "barrier effect". The microbiota can also break down the toxins produced by pathogens.
  • Development and maturation of the immune system. The intestine hosts 60% to 70 % of our immune cells. The microbiota is essential for the formation and subsequently the functioning of intestinal and general immunity.

Metabolic and physiological roles:

  • The microbiota plays a role in the absorption of carbohydrates and fatty acids, in the storage of fats and in regulation of the appetite...
  • It produces active substances in the brain: the microbiota produces the same neurotransmitters as the brain; it is part of the dialogue between the brain and intestine.
  • It produce vitamins, B group and vitamin K.

A sensitive and fragile microbiota

Dysbiosis, my microbiota isn't rightMany factors can unbalance the intestinal microbiota: this is known as dysbiosis.

This imbalance disrupts the functions of the microbiota and may lead to "leaky gut syndrome", namely a porous, permeable intestine.

Etanchéité des cellules de l'intestin

Etanchéité des cellules de l'intestinIn practice, the "cement" that seals the intestinal cells is partially destroyed and the intestine lets through certain substances or even microbes, which enter the blood circulation placing the intestine and/or the body in a state of chronic inflammation, a source of problems. The integrity of the mucosa is affected, as well as the intestinal absorption of dietary nutrients.

But frequently, in the event of discomfort, the link is not made with the intestine, and especially its microbiota, which is "unwell".

And if this comes from my intestine?

My observed imbalance

What are the reasons?

I'm tired all the time.

The microbiota enables absorption of vitamins and minerals, especially magnesium, iron and calcium. So be careful about any deficiencies.

I have intestinal discomfort (bloating, gas).

There are 2 main flora: from fermentation (breaking down of sugars) and from putrefaction (breaking down of proteins). If one or the other dominates, you have abnormal gas production.

My transit is abnormally fast or slow.

In the majority of cases, the flora is either colonised by a pathogenic germ or under-diversified.

I have cravings or I'm not hungry.

The microbiota plays a role in appetite regulation.

I have an allergic environment.

The flora is in direct contact with 70% of our immune cells and contributes to allergy regulation.

I'm always ill.

The microbiota stimulates general immunity.

I have difficulties with memory and concentration.

A balanced flora produces substances that promote the longevity of the nerve cells in the brain which are involved with memory.

I am stressed or anxious.

A microbiota which is "well" slows down stress messengers and engages the neurotransmitters that promote calmness (GABA, serotonin).

I am overweight, have high cholesterol, diabetes...

The flora plays a role in the metabolism of sugars and fats.

How do you rebalance the microbiota?

1. First of all, adopt a healthy lifestyle:

  • Take more gentle exercise; violent exertion destabilises the flora;
  • Get plenty of fresh air;
  • Take your time to chew well and digest properly;
  • Avoid excess (sugar = fermentation+++, proteins = putrefaction+++, trans fats and sweeteners = disruption++++ of the flora).

2. Regenerate your flora with "good" lactic ferments

Lactic ferments, also called probiotics, are defined by the WHO as "living micro-organisms, which, when consumed in sufficient quantities, produce a beneficial effect on the health of the host". They pass through the digestive tract influencing the microbiota and intestinal mucosa.
The lactic bacteria (transforming "coarse sugars" into lactic acid, hence the name) are among the main categories of probiotics. Lactobacilli and bifidobacteria are the most frequently used.
But not all strains have the same properties. Some help rebalance our intestinal flora, others improve transit, promote absorption of minerals and vitamins and yet others strengthen the immune system.

Their effect therefore depends on the strain of the bacteria and also on the dose which, in order to be active, must be of at least one billion bacteria.

Taking care of the microbiota through diet

Dietary habits have an important impact on the composition of the intestinal microbiota from the early years of life. Accordingly, the composition of the microbiota among breastfed babies is richer in lactic bacteria and bifidobacteria than that of babies fed on formula; the microbiota will also vary depending on whether you follow a vegetarian or meat-eating diet.

A "good" flora is characterised by both its bacteria diversity and quantity

Certain foodstuffs enable you to maintain a balanced microbiota:

1. fruits and vegetables, sources of dietary fibre, which therefore act on bacteria - notably bifidobacteria - for the digestion process. Best consumed raw and well chewed or lightly steamed.

Favour those with a prebiotic effect, namely which act as food for the microbiota bacteria enabling them to multiply: artichoke, asparagus, banana, onion, figs, Jerusalem artichoke, white part of the leek, garlic...

2. foods rich in lactic ferments naturally found in raw sauerkraut, yoghurt, fermented milk (ribot, kefir), fermented cheese...

The "find out more" box at the end of the article with the books remains unchanged

The "therapeutic" microbiota?...

Over the last few years, the microbiota has become more and more interesting to the scientific community, doctors and researchers. With no end to the surprises concerning its roles and benefits in the body, new discoveries are regularly being made. So they medical applications are envisaged, based on the transfer of microbiota from a healthy donor to a recipient patient, in order to improve their state of health.

Did you know ?

Quand l'intestin dit NONQuand l'intestin dit non 
(When the intestine says no)

Doctor Jacques Medart
Editions Thierry Souccar
April 2008

Mes petites recettes magiques aux probiotiques et prébiotiques Mes petites recettes magiques aux probiotiques et prébiotiques
(My magical little recipes for probiotics and prebiotics)

Danièle Festy
Editions Leduc
November 2010