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Microbiota: our intestines “think” with 200 million neurons

Scientists show us that the brain in our cranium is not the only master on board. They explain that the millions of neurons in our belly, and the hundreds of billions of bacteria with which we live in symbiosis, influence our emotions and personality!

The documentary Le ventre, notre deuxième cerveau” by Cécile Denjean (France 2013, 55 min) broadcast on Arte, is a fascinating scientific investigation awarded the Grand Prix “AST – Ville de Paris” at the Pariscience 2014 festival on October 6.

Intestinal microbiota: more bacteria than human cells

We are composed of more bacteria than human cells: we are more bacterial than human!

We thought that our biological composition, with its millions of human cells, represented our little person! Well, NO, each human being that we are is an ecosystem in itself, hosting more bacteria than there are stars in our galaxy.

The total number of our human cells is less than the number of bacteria that inhabit us.So we’re one with nature! We are bacterial ecosystems, bathed in a bacterial environment, ensuring biological continuity with it.

Different species of bacteria and types of microbiota

The little beasts that dominate the big ones…

Our bacterial population, without which we couldn’t live, influences not only Who we are, but also How we are!Our bacterial population, or microbiota, has been classified into three distinct categories called “enterotypes”. These enterotypes are distinguished by the amount of energy they provide.

We are therefore defined by our enterotype (microbiota group) in the same way as we are by our blood type!

Our microbiota, like our genetic heritage, has a huge influence on our health. It would seem that certain bacteria, or sometimes the absence of certain bacteria, are responsible for the emergence of certain pathologies. Scientists have shown that analysis of our intestinal bacteria could reveal predispositions to type II diabetes, cardiovascular disease, liver disease…

Neurons in the gut: our belly is a concentrate of intelligence

200 million neurons line the walls of our intestine!

That’s the same number of neurons that make up the cortex of a small animal (a dog, for example)! We knew that our emotions had an influence on our belly. Scientists have now discovered that our belly also influences our emotions. What we call our second brain is in fact our first or original brain. So we have a cerebral cortex and a belly. These two brains are interconnected, constantly communicating.

L'estomac, un concentre d'intelligence
The stomach, a concentrate of intelligence

The cortex: the upper brain with a central nervous system
The belly: the lower brain with an enteric nervous system

Our two nervous systems are connected. They communicate in the same language via the vagus nerve. Brain and belly use the same words to communicate: neurotransmitters.

Scientists believe that irritablebowel syndrome is a consequence of a lack of communication between the two brains. Neurons in the gut are rendered hypersensitive. Many mysteries still surround these illnesses.

Serotonin is a word or neurotransmitter whose meaning changes according to context. In the upper brain, serotonin means well-being. In the lower brain, serotonin regulates our intestinal transit and our immune system.

95% of serotonin is produced in our belly. It acts in the digestive tract and circulates in our blood. It then reaches the hypothalamus, the part of our upper brain that manages our emotions.

We knew that our emotions had an influence on our belly, now we know that our belly also influences our emotions.

Our intestine is a window onto our brain

Le système nerveux
The nervous system

Because of the anatomical similarities between neurons in the cortex and those in the gut, scientists now know that the gut is a window to the brain. While brain samples are extremely delicate and usually taken post-mortem, intestinal biopsies can be performed routinely.

Scientists have shown that intestinal wall biopsies enable early diagnosis of Parkinson’s disease. Parkinson’s disease causes severe digestive disorders that appear some twenty years before the onset of motor problems. Such early diagnosis of the disease will enable better management.

This approach represents an exceptional medical advance for this neurological pathology, which is affecting more and more people. It also opens up new possibilities for neurological diseases such as depression, Alzheimer’s, autism and other mental illnesses.

In the near future, we’ll be able to detect diseases or predispositions to disease simply by observing our gut.

Our three brains

Our three brains make us who we are, they dictate how we are.

We thought we were superior organisms with 1 brain, when in fact we are merely bacterial vehicles, ecosystems under the influence of 3 interconnected, interdependent brains: the top brain (the one we thought was all alone), our gut and our microbiota.

How can we strengthen our microbiota and intestinal balance?

It’s vital to strengthen your microbiota and maintain a healthy intestinal balance by…

Avoiding antibiotics, analgesics, anxiolytics, antidepressants…
Eating carefully, both in terms of quantity and quality.
Maintaining a healthy lifestyle, with daily physical activity, sufficient rest, controlled stress…

Why are micro-algae such as chlorella so valuable and restorative for our health? Isn’t it first and foremost because they help to cleanse and balance our intestines?

The vast majority of consumers of organic chlorella report rapid regulation of intestinal transit, followed by a feeling of soothing and general well-being.


“Le ventre, notre deuxieme cerveau de Cécile Denjean, France 2013, 55 min – ARTE

Note from the eChlorial team
We would like to stress that the people interviewed or who testify on our blog do so in all sincerity without any conflict of interest.


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