- The cerebral and intestinal axis - why our intestines are the "second brain"?
- What influences the brain-gut axis?
Help the development of the site, sharing the article with friends!
Have you ever wondered where does "feeling" come from? It turns out that our head is not entirely responsible for them. Well-being is born somewhere in the brain-gut signaling (the gut-brain axis). The complicated information exchange takes place in 90%. towards the brain and only 10 percent. feedback. It is the intestines and the organisms that inhabit them that send signals - mainly through the vagus nerve - about how we feel. This explains why, when stressed, we feel tight in our stomach, and when experiencing amorous elevations, we feel butterflies in our stomachs. Many diseases, such as depression, also have their origin in the gut.
The brain-intestinal axisis the signaling pathway between the gastrointestinal tract and the central nervous system. The vagus nerve is responsible for it, but one by one …
The digestive tract consists of the esophagus, stomach, small and large intestines, and other organs such as the pancreas and liver. Together with the central nervous system, they form a network calledgut-brain axis , GBA.
The cerebral and intestinal axis - why our intestines are the "second brain"?
What reactions take place on the brain-gut line? The structure of the gut-cerebral axis is very active. Communication at the level of the brain-gut takes place constantly on various levels around the clock. The communication route is a highly unnerved network that creates:
- the only vagus nerve that leaves the head and neck area - "wanders", hence its name. It belongs to the autonomic nervous system of a parasympathetic nature (responsible for rest, improving digestion),
- dorsal root ganglia, the posterior root of the nervous system, on the one hand with peripheral receptors and on the other hand with the spinal cord,
- the autonomic nervous system, working "automatically" - divided into the sympathetic and parasympathetic parts, both acting antagonistically.
In addition, communication also takes place on the brain-blood-intestine plane through cells of the immune and hematopoietic systems (including bone marrow), which respond to the following signals:
- autocrine(independent - the cell produces the hormone itself and reacts to it itself, the so-called positive feedback),
- parakrynne(local -the cell stimulates neighboring cells to produce hormones without the participation of the circulatory system),
- endocrine(long-distance - stimulates the production of hormones even in distant organs, using the circulatory system).
The integral barrier of the gut barrier is the gut barrier, which consists of:
- intestinal microbiota,
- cells of the intestinal epithelium and enterocytes,
- endothelial cells,
- vessels of the lymphatic system,
- transmembrane tight junctions.
The intestinal barrier largely resembles the blood brain barrier (BBB), which includes:
- endothelial cells, astrocytes,
- microglia cells and lymphatic vessels,
- transmembrane tight connectors.
The following also plays an important role in the functioning of the brain-gut axis:
- hypothalamic-pituitary-adrenal (HPA) system
- stress hormone - cortisol,
- short chain fat acid (SCFA),
- enteral nervous system (ENS).
The effects of the interaction include the influence of the gut microflora, which is involved in the regulation of anxiety, pain, cognitive dysfunction and mood by stimulating specific areas of the nervous system.
Read also: Good bacteria in the body: microbes that protect against disease
What influences the brain-gut axis?
Dysbiosis
It is a dysfunction of the intestinal microflora (the term intestinal microflora used conventionally is incorrect, because flora refers to the world of plants, and as you probably already know, the intestines are inhabited mainly by bacteria), it can cause the intestinal barrier to unseal and affect the function of the brain-intestinal axis cellular and bacterial origin. This includes compounds such as hormones, cytokines, chemokines, and products of bacterial metabolism.
Infections
Metabolic disorders or genetic predisposition (e.g. mutation C1orf106 in patients with inflammatory bowel diseases) may significantly affect the transmission of information between the gastrointestinal tract and the brain.
These disorders are manifested in the form of various diseases. The most frequently observed disorders are dyspepsia, a irritable bowel syndrome, which according to the new definition is called disorders of gut-brain interaction.
Disorders of the brain-blood-gut axis also apply to patients with autoimmune liver diseases, fatty liver disease and cirrhosis,metabolic disorders, obesity and celiac disease.
Interestingly, a frequent consequence of these disorders is depression, which accompanies diseases of the gastrointestinal tract.
Modulation of the cerebral and intestinal axis is now an important element in the prevention and treatment of civilization diseases.
Modifiable factors
The impact may be lifestyle modification, appropriate diet, various types of behavioral techniques, modulation of the gut microbiota and pharmacotherapy.
Microbiota - antibiotic therapy
Some functions on the brain-intestine line may be impaired even by distant antibiotic therapy. Long or repeated therapy is especially dangerous.
Disorders associated with taking antibiotics lead to an increased risk of cancer or neurodegenerative diseases, even several years after antibiotic therapy.
Depending on the composition of the intestinal microflora, the body is able to use the same substance in a different way, the metabolites of which have different effects.
An example would be tryptophan. An essential, exogenous amino acid that the body cannot produce on its own, so it must be supplied with food.
Only some bacteria inhabiting the intestines have the ability to synthesize this component. Tryptophan is involved in a number of reactions in the body, and its role is closely related to mental he alth and well-being. The transformations of tryptophan are the source of important compounds: tryptamine, serotonin, melatonin, niacin.
Read also: Probiotic - healing properties, types and sources
Biosynthesis of active ingredients from tryptophan
Biosynthesis of active ingredients from tryptophan yields biologically active substances such as indoles and other compounds. Intestinal bacteria influence the synthesis.
a)Indoles- are produced from tryptophan by the bacterial tryptophanase, which is a group of enzymes inside cells.
These enzymes produce Clostridium sporogenes (a type of gram-positive bacteria) that metabolize tryptophan into indole and then into 3-indolpropionic acid (IPA), a very powerful neuroprotective antioxidant that traps hydroxyl radicals.
IPA binds to the pregnane X receptor (PXR) in intestinal cells, thereby facilitating mucosal homeostasis and gut barrier function. Once absorbed from the gut and transported to the brain, IPA has a neuroprotective effect which prevents cerebral ischemia and reduces the development of Alzheimer's disease.
b)Lactobacillus species- metabolize tryptophan into indole-3-aldehyde (I3A),which acts on the aryl aromatic hydrocarbon receptor (AhR) in the gut immune cells to increase the production of interleukin 22 (IL-22).
The therapeutic use of IL-22 is currently being investigated in the treatment of diseases such as psoriasis, ulcerative colitis, and liver and pancreatic diseases.
c) Samindoletriggers the secretion of glucagon-like peptide-1 (GLP-1) in intestinal L cells and acts as a ligand (i.e. receptor binding molecule) for aromatic hydrocarbon receptors AhR.
d)Indolecan also be metabolized by the liver to indoxyl sulfate, a toxic compound in high concentrations and associated with vascular disease and renal dysfunction. AST-120 (activated carbon), an intestinal sorbent taken orally, adsorbs indole, which in turn reduces the concentration of indoxyl sulfate in the blood plasma.
About the authorMikołaj Choroszyński, nutritionist and gastrocoach Master of Human Nutrition and Dietetics, Psycho-dietician, Youtuber. Author of the first book on the Polish market about a diet counteracting neurodegenerative diseases "MIND Diet. A Way for a Long Life". He fulfills himself professionally, running his Bdieta diet clinic, because nutrition has always been his passion. She helps her patients by telling them what to eat to stay he althy and look good.Probe