Gut and Brain an alliance, supported or disturbed by microbiom
Milliards of bacteria living in the gut, a sensitive System with enormous influence

How your gut can influence your Brain?

The latest research in neuroscience and biopsychology spot on the interactions between the brain,

the gastrointestinal tract and the bacteria within the gastrointestinal tract. It is in both

directions and called the brain–gut–microbiome axis. Gut bacteria have an influence on

cognition and stress‐related behaviors and the pathogenesis of a number of disorders in

which inflammation is implicated, such as mood disorder, autism-spectrum disorders,

attention deficit hypersensitivity disorder, multiple sclerosis, and obesity, anxiety, and

depression. It is important to know and support the role of the axis in humans and improve

health by prevention and intervention aiming this system. Obviously, we have to understand

that functional gastrointestinal disorders such as irritable bowel syndrome are a disorder of the

axis and not an isolated problem of the gastrointestinal function. The researchers of how

microbes within the body can interact with human brain and behavior show more

interactions of human psychology as an obviously holistic manner. We have to ask ourselves

did the way we changed our environment, our food our habits, change our gut microbes? May

this be one reason for increasing disorders and psychological problems? What could be ways

to support our gut microbiome and prevent negative impact on Brain?

Your Gut your brain and your Behaviour

Let´s spot on microorganisms because the intestines are a place of a rich diversity of bacteria.

These bacteria are important for numerous physiological functions, as digestion and

preservation of intestinal barrier. The gastrointestinal tract has an own nervous system. The

brain communicates to the gut, which influences its sensory and secretory function, and in

return, it receives information from the gut. This communication between the gut microbiome

and the brain uses not only the autonomic nervous system but in addition neuro endocrine

and neuroimmune pathways. Bacteria from the gut can produce neurotransmitters that can

also be found within the central nervous system. There is evidence which suggests that the

diversity of the gut microbiota may be related to brain structure as well. Stress can disturb this

chemical and nervous communication.

Stress is a killer – for your gut microbiota?

In frank, it is not that easy to tell but stress can disrupt the homeostasis of an organism Stress

can change the composition and function of the gut microbiota. Even a mother’s stress during

pregnancy can change the child’s gut microbial. In the same way, dysbiosis can occur due to

chronic stress in early life and into adulthood.


Acute stress has less relevance on the gut bacteria than a chronical exposure. Acute stress has

been found to be associated with potentially adaptive immune responses (suppression of

immunity mounted against intracellular pathogens, but a preservation of immunity mounted

against extracellular pathogens), whereas chronic stress has been associated with a

suppression of both. There is a lack of studies in humans because examiners only way to test

is the stool. But animal models show clearly that stress impacts upon the

brain–gut–microbiome axis. Gut microbiota is altered in patients with major depression, as

well as irritable bowel syndrome. The role of the vagus nerve is particularly interesting here, as

evidence suggests that gut‐brain signaling may be mediated by the vagus nerve.


How Bacteria influence Cognition?

In animal models, the gut microbiota has been shown to interact with host cognition in

numerous ways. In mice, researchers switched off the microbeam of the intestinal flora, with an

antibiotic cocktail. This mouse showed more anxiety. Compared to untreated animals, they

observed much less newly formed nerve cells in the hippocampal region of the brain. The

same mice showed impaired short‐term recognition and working memory because this

formation of new brain cells – called "neurogenesis " – is important for certain memory

functions.Further more the researchers observed altered social behaviour. After re-colonisation

the social behaviour is restored but not social cognition. An another study could reveal that

maternal high‐fat diet had a negative impact on mice offsprings social behaviour that was

reversed by treatment with Lactobacillus Reuters. In rodent models, a specific strain of

Bifidobacterium longum was found to alter cognition as well as stress‐related behaviour and

physiology. Researchers assume the changes may occur due to neurological changes such as

increased myelination in the prefrontal cortex in germ‐free mice, a change which could be

reversed by the restoration of the microbiota. Of course, these results have to be handled with

reason and care until clear human studies are provided. Nevertheless they show obvious connections

between gut – bacteria, brain function and behaviour.

Developing to a healthy person needs a healthy gut in early childhood

Researchers assume sensitive periods for the development of the gut microbiota. The

microbiota of vaginally‐delivered infants differs from those delivered by cesarean. The initial

exposure to the vaginal microbiome on birth leads to a different population of microbes

colonising the gut compared to cesarean delivery. Human psychological and microbial

development are impacted by perinatal factors. Other factors shortly after birth could also

affect the microbiota, such as the use of antibiotics, and feeding pattern, which can result in

impact upon neurobiological development.

Can gut microbes be involved in Autism?

In result of researchers, the evidence is given that the gut bacteria influence social behaviour.

Altered social behaviour in germ‐free animals is complemented by indicators that children

with autistic spectrum disorder (ASD) have a differing gut microbial profile. Researchers

assume that immune pathway within the brain–gut–microbiome axis may be a plausible may

be the cause of the social behaviour. Inflammation in the gut may have social behaviour as a

result but same time, a social threat may lead to a proinflammatory immune response.

Globalisation, modern Lifestyle and the change of the guts

As we saw, social environment can have multiple influences on the gut microbiome. One may be

the change in diet due to Globalisation. A modern diet, high in carbohydrates and processed

foods influences the gut microbiota. Studies found differing and often more diverse

microbiota in populations with diets that are differing from this modern style. Studies

compared here with people of different origins, where the diet is similar to when agriculture

and animal husbandry were introduced c. 10,000 years ago. Concluding, that our diet made by

culture may become our fate for health, cognition and behaviour via the brain–gut–microbiome


The modern way of growing and farming is generally designed to reduce microbial diversity.

The herbicide Glyphosate is used world wide. In Europe, it was in a discussion but it was not

banned. It was found a strong coherence with Glyphosate, the gut microbe and the

detoxification of Xenobiotics. Via the gut, macrobiotic Glyphosate inhibits Cytochrome P450

(Cyp450) as a result, many toxins accumulate in a higher dose in the body and cause several

secondary damages.


May your diet change your Psychology

Research, as mentioned above shows clearly: yes. A vegan diet reduces in the potentially

pathological microbiota, a high‐fat diet increase risk of inflammation. If you like to control

your gut microbe, just learn to control your diet. Research of polyunsaturated fatty acids

showed in laboratory animal models to alter microbial composition as well as improving

cognition and to enhance adherence of probiotic bacteria to the gastrointestinal tract Research

in humans discovered that docosahexaenoic acid, eicosapentaenoic acid, and total omega‐3

polyunsaturated fatty acids in people with major depression are low and omega‐3 fatty acids

may have a positive effect on depression. These are only very few samples how diet impacts

the microbial and by this way healthy and happy.

Pro- und Prebiotika

Probiotics are living bacteria, that when ingested in sufficient quantities, help to change and

improve the gut microbes. For example, probiotics are able to reduce cortisol output in

response to an acute stressor. Even probiotic fermented milk drink can change brain activity.

Another study indicated that fermented milk of a Lactobacillus Helveticus provides improved

sustained attention and a well as a recent study shows changes in frontal EEG and better

learning memory performance. There are several hints why these effects can be induced,

including immune system effects, vagus nerve activation, tryptophan metabolism, and

microbial metabolites. Probiotic bacteria can promote the production of neuroactive

substances such as serotonin and GABA.Research clearly shows that probiotics can influence

anxiety and depressive symptoms. Probiotics as Lactobacillus Plantarum showed an effect on

irritable bowel syndrome, the pain was reduced. Hint: In researchers, the effect of Probiotics is

tested mainly with only a few types of bacteria. At present, there is no upper limit for levels of

histamine and tyramine in fermented products available, which may cause issues, especially

in individuals with sensitivities and/or defect enzymes like DAO and HNMT. For this case

Supplements may be recommended because they are composed well. Pay attention to take

supplements that have sufficient quantities of bacteria.

Prebiotics are food ingredients that improve health by modulating the colonic microbiota.

Fiber is, in general, an important part of a microbial supporting diet, because it is the main source

of microbiota-accessible carbohydrate in the diet of humans. There is different special fibre

available to support digestion, like Psyllium Husk. A well-researched prebiotic is inulin (not

insulin!) a nondigestible oligosaccharide. A study showed it is stimulating Bifidobacterium

adolescents and Faecalibacterium prausnitzii.


The role of gut microbes, probiotics, and vitamins

Vitamin B12 (cobalamin) is one Vitamine of the Vitamin B group, which is

known to support the nervous system and brain function. Vitamin B12 and other B-

vitamins can be produced by typical probiotics like Bifidobacterium, Lactobacillus.

The most famous B12 producer is Lactobacillus Reuters is naturally found in human

intestines. This may be beneficial in fermented food and in the human gut. At least two

groups of organisms in the small bowel, Pseudomonas and Klebsiella sp., may

synthesise significant amounts of the vitamin, too, as well, as Escherichia coli.

Vitamin B9 is a very important Vitamin for Methylation. Lactobacillus Plantarum

are expected to produce folate L. Plantarum is found in fermented food. Other

Probiotics which are likely to produce Folate:

– Bifidobacterium animals (used in Danone & Bifidus yogurts like Activia)

– Bifidobacterium locum (used probiotics)

– Lactobacillus acidophilus (most common probiotics)

– Lactococcus lactic (used to make buttermilk and many kinds of cheese including Brie,

Camembert, Cheddar, Colby, Gruyère, Parmesan, and Roquefort)

– Leuconostoc lactic (used to make kefir and sauerkraut)

– Streptococcus thermophilous (used to make yogurt)

Vitamin B2 Lactobacillus fermented, which is found in sourdough and in many

probiotics. It is also noted for its ability to reduce cholesterol levels and to act as an

antimicrobial and antioxidative. Research is not far on this matter, but it is sure,

that probiotics and gut microbiota can produce some of the Vitamins which are

very important for the nerve system.

Research data demonstrate that vitamin D regulates the gut microbiome and that

deficiency results in dysbiosis, leading to greater susceptibility to injury in the gut.

Just some thoughts by the author:

Some people are critical against this holistic way of disorders and disease. But just mind the claimings here are based on scientifical research, not traditions or experience. Gut may not be the cure of all disease and it is not the core. But it is involved in many symptoms and syndroms and can turn things to a better or a worse, so it is worth minding it. Gut is not only involved in the brain axis. There is many other organ and health systems and comminicating connections. Gut plays infact a main role in a network involved in health and benefit or weakness and disease.



You may also like:

Psyllium Husk – effect not only in the intestine