Rich inner world: how the digestive system affects our mood
Health / / December 19, 2019
The digestive system of any living organism is literally teeming with a huge amount of bacteria. Just imagine: at this very moment you are in the hundreds of trillions of microorganisms that inhabit alimentary tract. Microbial cells are much larger than the very cells of the body (which is about ten trillion). If you is not enough impressive, then I think that collectively, all these microbes gene is 150 times larger than the actual human.
Scientists still try more precisely find out what kind of bacteria make up the human microbiome. According to preliminary data, it contains about a thousand species already studied bacteria and even seven thousand completely unexplored. So someone who, as our digestive tract is rarely alone.
Human microbe is a collection of microorganisms that inhabit our body both from inside and outside. The most studied part of the microbiome is considered intestinal microflora, so that the highest concentration of bacteria is concentrated there.
The microorganisms in the digestive tract are essential for mental health. Condition of the gastrointestinal tract affect our appetite and the mood is much stronger than we think.
Ted Dinan (Ted Dinan), professor of psychiatry and scientific director of the Center for alimentary farmabiotiki University College in Ireland, became an expert in the study of bacteria almost by chance. This happened in the early 2000s, when he had just been hired. Ted himself at that time described himself as a man who, with his crazy ideas are constantly distracted very employed and microbiologists from this accident, which at the moment is just a type of bacteria was investigated as probiotics.
probiotics - these are bacteria that are beneficial to our health. They improve the intestinal flora and are close in structure to the human body's own bacteria. Of these types of probiotics like lactobacillus and bifidobacteria, you probably have heard in the yoghurt commercial.
As expected from a psychiatrist, Dinan decided it would be very curious to see what happens if the feed probiotics experimental rats and observe their behavior. To this end, he spent the next experiment: shortly after birth rat pups were separated from their mother, that they provoked the development of depression and a significant decrease immunity.
Then scientists while giving them a special probiotic called Bifidobacterium infantis, after the adoption of which the rats returned to normal immune system, and signs of depression and anxiety was much less. After this incident, Dinan and his colleagues offered introduce a new term "psihobiotik" to refer to a specific class of microorganisms that have a positive effect on behavior and brain activity.
Ted Dinan, a professor of psychiatryPsihobiotiki - bacteria that when ingested in sufficient quantities can benefit the health of patients suffering from mental illness.
History study microbiome
The hypothesis that the processes occurring in our digestive tract, greatly affect mental health, are hardly new. Medicine has for many years tend to blame our gastrointestinal tract in all imaginable and unimaginable troubles.
It all started with the fact that in the early 1800s, the military surgeon and physiologist William Beaumont (William Beaumont) was a pioneer in the field of gastroenterology, studying the secretion of the stomach. The case was unusual: the patient Beaumont shot wounded in the stomach during hunting time. Because of this, in his abdominal cavity formed quite a big hole, which in any did not want to be delayed. This gave Beaumont the opportunity to scrutinize the work of the digestive system. He lowered into the hole bits of food and watching what is happening with them. That is how a scientist and found that for digestion are not only reducing the stomach wall, but the gastric juice, which dissolves the food.
By the early 1900s, doctors and scientists have conclusionThat should be considered the digestive system as a kind of hotbed of huge amount of mental illness. Even then, they are quite seriously believed that the bad intestinal microflora may well be the cause of increased fatigue, melancholy and many neuroses.
An interesting and very recent experience, delivered to mice Jane Foster (Jane Foster), a neuroscientist at McMaster University in Canada. during the experiment Jane tries to prove that there is a direct connection between the brain and the microflora - axis "gut - brain".
For the experiment, two types of mice were used: conventional and sterile, in which the microflora was completely absent. To seeing them put in a special box, one part of which was darkened, and the other was in the light. Conventional mouse longer studied darkened region and sterile spent more time on the light side of the box. This implies the assumption that anxiety without microflora appears much smaller and mouse simply does not feel possible danger.
In another study, it was foundThat microbes affect genes associated with myelin, the material that covers the protective layer of the nerve fibers. It is produced in the prefrontal cortex of the brain responsible for behavior and preservation of concentration. If this part of the brain are damaged, the person becomes more susceptible to numerous mental disorders, including schizophrenia and severe forms depression. Studies have focused on trying to figure out how the microorganisms of the digestive system affect the development of these diseases.
The gastrointestinal tract has its own nervous system, which is called enteral. With its help the bacteria in our intestines can send to the brain specific chemical signals. It is important that this system is working properly, since some types of bacteria contain the most important neurotransmitters, such as:
- Acetylcholine (involved in the transmission of impulses in different parts of the brain);
- gamma-aminobutyrate (eliminates hyperphrenia);
- tryptophan (improves mood).
In one study, Ted Dinan and colleagues decided feed probiotics mice similar to those generally added in yogurt. Mice that received the probiotic, behaved less anxiously and actively explore the proposed part of the labyrinth, timid mice became more sociable. In addition, these mice had higher levels of gamma-aminobutyric acid, which is responsible for the elimination of mental excitement and reducing anxiety.
In another experiment, the researchers transplanted microbes from the intestine of mice suffering from depression are common in the intestines of mice. It was found that mice whose behavior used to be normal, adopted restless habits of those relatives whose bacteria they have replaced. This experiment allowed Dinan suggest that the gut and brain are connected directly via the vagus nerve.
The vagus nerve - one of the nerves that comes out of the jugular foramen of the skull and down the neck to the chest and abdominal cavity. With the help of the brain receives information about what is happening in the human body.
Prospects study microbiome
So far, all studies were conducted only on mice, but the human body is affected. Effect of probiotics on our well-being yet little studied, but it gives an incentive to move forward.
The only study that was conducted on humans, was as follows: 40 absolutely healthy participants in the experiment were divided into two groups. For four weeks, half of them took eight species of beneficial bacteria, which have been designed to alleviate any symptoms of depression and anxiety. The second group was given a placebo. After the end of the experiment all the participants tested on a scale of depression. The subjects who received the good bacteria were significantly less prone to displays of sadness and depression. However, we should not exaggerate the importance of this study.
Lack of evidence - is not considered a reason that psihobiotiki not work in humans. Invisible axis "gut-brain" - a very complex system, which has yet to be only carefully examine. For example, the researchers plan to find out which bacteria in the body are the most important for its full operation, as well as by what it psihobiotiki biological mechanisms affect our mood.
Jonathan Eisen (Jonathan Eisen), a professor of the University of California, says that figuring out which microorganisms are important for the intestinal flora, will be a crucial step in the development Gastroenterology. If the change of microflora can influence behavior, then just need to understand how it works.
Further study microbiome will be useful for the development of both medicine and dietetics. There is no reason to doubt that the change ration Power will entail changes in the digestive system. It is therefore important to examine whether it is possible to influence the bacterial contents of the digestive tract to achieve from diet best results. As for the medicine, then the body in people with certain diseases have specific microbes that this disease is triggered. If you learn how to properly remove them, then the recovery may occur faster.
Ed Yong (Ed Yong), a British scientist, writer and journalistThere is no normal or healthy microbiome, which should be pursued. Microbes are complicated, it is constantly changing and depends heavily on the human condition and what it eats.
In the study of the digestive tract too many false hypotheses and unproven facts. Communication microbiome and depression still has not been proved, but it does not prevent people to make assumptions about it a different degree of absurdity. Jonathan Eisen on his blog even offers to give out for especially delusional fantasies special award.
With regard to serious research, the problem of studying the microbiome is quite acute. For example, the National Institute of Mental Health in the past two years has allocated 3.7 million dollars to study the role of the microbiome in mental health, management The US has also funded a study of the microbiome of Naval Research, and the European project called MyNewGut began to study the connection between the brain and the digestive tract. It is already clear that in the end, scientists get to something interesting, but so far need to be patient.
The history of biomedical research is full of examples of how out of seemingly meaningless speculation grew grandiose hypothesis and discovery. The most striking example can be considered as the project "Human Genome". A quarter century ago, when the work on the project has just started, the researchers hoped to determine the sequence nucleotides that make up human DNA, which would lead to the discovery of cures for many genetic diseases.
These great results work did not lead on the project, but the scientists were able to decipher the human epigenome. It combines all the factors that determine which of the genes that make up the gene function, and what - no. It was a great discovery. Now microbiome studies do almost the same rate. But do not forget all the same that the opening is not so simple in this area as seem at first glance, and the answer to the ultimate question of life, the universe and everything else they just will not give.