The brain-gut axis

In recent decades scientists have begun to talk about overall human health and healing often referred to as "mind and body healing." The brain-gut axis is a living example of the two-way communication of thought and emotion. This axis consists of a network of biochemical signals, which takes place between the gastrointestinal tract and the CNS, including the hypothalamic-pituitary-adrenaline axis.
The vagus nerve is one of the brain-gut lines of communication, as it travels all the way from the head to the belly via chemical messengers, the neurotransmitters. When the intestinal flora is underfunctioning, then the production of neurotransmitters decreases and the performance of the brain shows a gradual deterioration in its mental processes.

Gut the second brain
Interest is growing around the role that gut function plays in a person's overall health. The intestinal mucosa throughout its course performs absorption and barrier functions between the intestinal contents and the inside of the body. With the intervention of various bacteria, enzymes, digestive fluids, the products of digestion are absorbed through the intestinal mucosa, so the body can rebuild tissues, produce energy, proteins and carry out other further complex mechanisms. The entire process of selection and absorption of nutrients is undertaken by the villi, which are essentially folds of the intestine and their main goal is to increase the functional surface of the digestive system.
A large population of different species of bacteria have so far been identified as part of the human intestinal flora. 85% of them help the survival function of our organism with their probiotic action.
The microorganisms that colonize the gut are involved in the production of key neurotransmitters.
Dopamine, serotonin, adrenaline, acetylcholine are neurotransmitters found in the CNS and involved in the transmission of nerve impulses. Most of these neurotransmitters are produced in the digestive system.