How gut bacteria affect the brain and behavior – healing practice

Gut flora: How do gut bacteria communicate with the brain?

Of the colon communicates via the so-called gut-brain axis with the Brain. This has already been proven in previous studies. How exactly this communication takes place, however, could not be traced in detail so far. An English research team has now identified gut bacteriathe the Communication between gut and brain influence significantly.

researchers of Square-Institute as well as the University of East Anglia in the UK were able to decipher how certain Gut bacteria enable communication between the gut and the brain. The results were presented in the journal Gut Microbes.

Influence of the intestinal flora extends to the brain

That microbiome in the gutoften as Darmflora is a complex community of bacteria, viruses, fungi and other microbes. The microorganisms are the most important regulator for the function of the intestine.

However, as studies in recent years have repeatedly shown, the influence of intestinal bacteria extends far beyond the intestines – to the brain.

The new research provides important pieces of the puzzle to complete the picture of the gut-brain axis. According to the study, bacteria living in the intestinal mucosa live, the brain and can even be involved in the development of neurological disorders.

Far-reaching brain changes without intestinal flora

On a group of mice bred not to Darmflora the working group was able to set up numerous defects in brain function as well as in the brain development document, such as

  • dysfunctions in the blood-brain barrier,
  • Dysfunction of microglial cells (immune cells that coordinate immune responses in the brain),
  • changes in the formation of new nerve cells (neurogenesis),
  • Changes in the adaptability of brain neurons.
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Stool transplantation affects gut-brain communication

It was also known from previous studies that Transmission of the gut microbiome by means of a Stuhltransplantation Influence on the signaling between the gut and the brain hat.

So far, however, there has been little information on how individual intestinal bacteria are able to influence this communication.

Sugar molecules in the intestinal mucosa

As the working group found out in mice with a healthy gut microbiome, some bacteria in the gut are able to use certain sugar molecules from the diet. These are so-called Mucin-Glykanewhich bind to proteins in the intestinal mucosa.

The bacterium Ruminococcus gnavus

The mucin glycans are thus closely associated with the tissue of the intestine. A specific type of bacteria called Ruminococcus gnavuswhich feeds on these sugar molecules, is in close contact with the intestinal cells in the intestinal lining.

R. gnavus is also a common member of the human gut flora. This type of intestinal bacteria colonizes the intestines in early childhood. The population persists into old age.

The bacterium has already been linked to inflammatory bowel disease in previous studies. Also in those affected with general anxiety disorders, migraines, depression or attention deficit hyperactivity disorder Overpopulation of R. gnavus to be determined.

R. gnavus releases metabolites in the intestinal mucosa

In the current research work, the research team has now been able to show how R. gnavus settles in the intestinal mucosa and feeds on the mucin glycans mentioned above. The bacteria set metabolites free who are known to have the affect brain function.

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For example, one of these metabolites is Tryptamina metabolite involved in the release of the neurotransmitter Serotonin triggered in the intestine. Serotonin, in turn, influences mood, pain perception and the sleep-wake cycle.

Brain function changed by stool transplant

Back to the mice: After the animals without intestinal flora received the intestinal microbiome of the healthy animals via stool transplant, the researchers were able to observe how the bacterium R. gnavus colonized the intestinal mucosa.

Shortly thereafter, the team could Changes in the regulation and functioning of the brain determine.

Among other things, there was a higher activation of the microglial immune system and neurogenesis in the brain region of the hippocampus. The animals also showed increased concentrations of metabolites released by R. gnavus.

R. gnavus is instrumental in gut-brain communication

Overall, the research suggests that the bacterium that lives in the gut lining Ruminococcus gnavus is instrumental in the communication between the gut and the brain is. An over- or underpopulation also seems to be associated with pathological processes.

New ways of treating neurological disorders

Influencing the intestinal microbiome through nutrition or other therapies such as stool transplants offer new starting points for maintaining mental health or for treating neurological disorders. Before that, however, the findings must first be confirmed in the context of clinical studies on humans. (vb)

Author and source information

This text corresponds to the specifications of medical specialist literature, medical guidelines and current studies and has been checked by medical professionals.


  • Nathalie Juge, Erika Coletto, Dimitrios Latousakis, et al.: The role of the mucin-glycan foraging Ruminococcus gnavus in the communication between the gut and the brain; in: Gut Microbes (2022), DOI: 10.1080/19490976.2022.2073784
  • Quadram-Institut: How do microbes living in our gut modulate brain and behaviour? (veröffentlicht: 24.05.2022),

Important NOTE:
This article contains general advice only and should not be used for self-diagnosis or treatment. He can not substitute a visit at the doctor.



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