An invisible axis the brain-gut

What is happening in our stomachs for many remains shrouded in mystery. But new research shows that the condition of the gastrointestinal tract affects our appetite and mood are much stronger than we thought.


The average person has about 1.5 kg of gut bacteria. A so-called enteric nervous system, located between the esophagus and intestine, and consists of 100 million nerve cells. Please note: there are more of them than in the spinal cord. This is the second complex cluster of nerves in the human body after the brain. Our brain, with all its feelings, emotions and thoughts constantly communicates with the “gut brain”. This process of communication is called “the axis brain – gut”.


The axis the “gut-brain” – an imaginary line connected and one of the new horizons complex neuroscience. Intestinal microflora, which is often now called the “second genome” and the “second brain,” may influence our mood through mechanisms that scientists are only beginning to understand. And, unlike the genes that we inherit, the microflora can be changed and even grown. As soon as studies are transferred from mice not people, we are getting more understanding of the relationships of microflora our brains become visible an important connection with the mental (or emotional) health. A Japanese magnate was once asked how he will know whether to join the deal and he replied: “I swallow it, and if I like the feeling in my stomach, I enter into a transaction”. Our gut with your own mind, but is continuously talking to our brain.


Digestion is a complex process, so there is nothing surprising in the fact that for its regulation there is a separate neural network. Digestive the nervous system is responsible for the processes of mechanical mixing of food in the stomach, coordinating the contraction of circular muscles and all of the sphincter throughout the bowel to ensure the progress of food, it also supports different biochemical environment and the level of acidity inside each individual section of the digestive tract, enabling the enzymes necessary conditions for their work.


Do not have to be a gastroenterologist to be aware of these reactions, or may be a more subtle feeling in my stomach that accompany emotions such as anxiety, excitement, fear or stress. For millennia, people were convinced that the gastrointestinal tract is associated with the brain and affect health. Only in the last century this relationship has been extensively studied. Two pioneers in this field was the American physician B. Robinson (published in 1907 his work titled “the Abdominal and Pelvic Brain”) and his contemporary British physiologist I. Langley, who coined the term “gastro-intestinal nervous system”.


In the early twentieth century Englishman Newport Langley calculated the number of nerve cells in the stomach and intestines — 100 million. More than in the spinal cord! There are no hemispheres, but in the presence of a branched network of neurons and supporting cells along with all sorts of impulses and signals. It has been suggested: is it possible to count such a conglomeration of nerve cells a kind of “ventral” brain?


It is noteworthy that the gut continues to function even when there is no communication with the brain and spinal cord. Intestinal brain to decide all aspects of digestion throughout the gastrointestinal tract – from the esophagus to the intestine and rectum. They used the same tools as the “noble” brain: a whole web of neural circuits, neurotransmitters and proteins. Evolution is evidence of his insight: instead of trying to force the head of the severely strain the activity of millions of nerve cells to communicate with a remote site of the body, she chose to entrust the management of the center, located in controlled areas.


According to modern concepts, the neurotransmitters produced by the neurons of the gastrointestinal tract, are not able to get into the brain, however they are still unable to penetrate a small area of the brain where the blood-brain barrier permeability is higher, for example, in the hypothalamus. Whatever it was, nervous signals sent from the gastrointestinal tract to the brain, no doubt, affect the mood. Researchers began to decipher the ways in which gut bacteria can signal the brain. Peterson and others have shown that in adult mice microbial metabolites affect the basic physiology of the blood-brain barrier. Gut microbes break down complex carbohydrates to short chain fatty acids with the formation of a mass of effects: the fatty acid butyrate, for example, strengthen the blood-brain barrier, “tightening” the connections between cells.


Coexistence of symbiotic microflora and its media, for the most part, mutually beneficial. In particular, the presence of symbionts is essential for the functioning of our immune system, digest nutrients and other aspects of healthy physiology. Using the most modern tools to study genetics and tissues at the molecular level, scientists were able to demonstrate that in the gut are a few types of bacteria, and that symbiotic populations are characterized by great variety: you can allocate up to thousands of different species. In addition, the formation of individual microflora is constantly influenced by such factors as gender, genetics, age, type of food.


In healthy people, biological diversity is much more but at the same time, studying the microflora of these people in different moments of time (a few months, you can see that the composition hardly changes. But in stressful situations or in response to physiological or dietary changes, microflora can also change, creating an imbalance in the interaction between microflora and its host. And such changes can affect human health.

Intestinal microflora (microbiota) – a huge population, important for healthy metabolism and brain function, and the communication between gut and brain is also through neural connections. The intestinal microflora is very important at an early age and can influence what reactions to stress will be developed in the brain

Probiotics (research on humans and animals have shown that probiotics or in other words “good bacteria”, have a positive impact on mood. Although this is a very promising open, no need to rush and think that we have already found a solution for clinical situations (disorders of conduct and mood). Of course, the microflora is an important modulator of health and must be considered a component of a complex, multi-faceted system of communication, which is necessary to establish a healthy balance for the development and healthy functioning of the brain.