“Zoo” of the body bottom. How gut germs control our behavior Healthy living Health

You go to the fridge, open it and see what you would like to eat for dinner. Boiled chicken breast with green salad or fried pork sausage with french fries? The voice of reason tells you to take the chest. But another voice inside demands relentless sausages, and your hand stretches them out. “The soul asks,” you sigh guiltily, sending once again a thousand calories of fatty fried food into your stomach.

You may be somewhat comforted if you discover that the issue here is not at all in the needs of your “soul” and not in the weak will, but in those microorganisms that live in your intestines. They are the ones who influence your eating habits, forcing you to consume those foods that you need yourself. On them, the invisible inhabitants of the gastrointestinal tract, depend well-being, mood, weight, smell, immune and general health – mental and physical -.

AiF.ru talks about how the microbiome controls our behavior.

I ate a burger – and “something tired …”

A study by scientists from the University of California was recently published. They found that certain gut bacteria can increase a person’s motivation to exercise and even improve their performance.

This study was based on another conducted in 2019. Then, analyzing the intestinal microbiome of 15 marathon athletes, the scientists observed an increased content of specific types of bacteria in it. And they concluded that these germs help convert the lactic acid produced by the muscles during exercise into a compound that increases endurance over long distances.

This time the experiment was performed on mice. They were divided into two groups: one consisted of trained runners, the other of ordinary. For 10 days they were fed with antibiotics that kill intestinal bacteria. The behavior of the rodents remained the same, but the “athletic” mice began to run 21% less and their results did not return even 12 days after stopping the antibiotic.

“We hypothesized that a set of gut bacteria would affect digestion and muscle function, as well as motivation levels, including exercise. “And our study confirmed that,” they commented on the results. author of the work, Professor of Biology Theodore Garland. – Although this is a poorly studied area, further research is needed, but it is already clear how important a balanced diet is. For example, a western diet high in fat and sugar negatively affects the biodiversity of the microflora. “This probably has a negative effect on athletic achievement and motivation for sport.”

In other words, burgers and hot dogs change the contents of our intestines in such a way that we are lazy to go to the gym or the pool. The number of beneficial bacteria decreases, along with them there is less energy available. Doing nothing all day, sitting on the couch in front of the TV, sometimes we wonder: “Why am I so tired?” And the reason, it turns out, is the lack of germs the body needs – they were the ones who started this vicious cycle.

Now scientists at the University of California want to create a drug that increases the motivation to exercise. Of course, based on bacteria. “If we can identify the germs we need, we can use them as a therapeutic agent to help ordinary people exercise more,” says Theodore Garland.

Calm down, Massa, I’m a bacillus!

Our intestines are inhabited by an entire “zoo” – about a thousand species of microorganisms (bacteria, viruses and fungi) that work day and night. They break down the molecules that make up food, start biochemical reactions, neutralize toxins, produce beneficial nutrients, build immunity and much more.

This ecosystem is unique and inimitable: no two people in the world have the same microbiome. Some physiologists even suggest that we consider the intestinal microflora as a complete organ of the human body – it is so important for our health and all its components work so smoothly. However, among the many “friends” of a person, there are many “enemies” in the intestines: they not only cause digestive problems, but also cause the development of cardiovascular disease, increase the risk of diabetes and cancer, contribute to anxiety disorders, depression, autism and Parkinson’s and Alzheimer’s diseases.

When we are overwhelmed by a feeling of happiness, we depict it with our hands pressed to our chests: it seems to us that the famous “hormones of happiness” are raging there. Alas, everything is much smaller: 90-95% of serotonin, the main neurotransmitter that determines our mood, is produced by gut bacteria. Just think about it: the germs that inhabited our “physical bottom” determine whether we are happy or not, whether we experience joy or sorrow and in general – what processes occur in our “rich inner world”!

The effect of microflora on behavior and mood, as well as on the development of depression, has been demonstrated in numerous experiments in laboratory mice. Irish neuroscientists added the bacterium Lactobacillus rhamnosus to the rodent diet – after which they swam more actively and their bodies released less stress hormones compared to the control group, where some animals gave up when they had problems. Canadian scientists have divided the mice into two groups – timid and courageous. and when the timid ones were transplanted microflora from the intestines of the brave, they began to show more curiosity about the world around them and rushed easily into adventures.

Researchers from the Baylor College of Medicine in Houston (USA) found that mice with autism have a reduced concentration of Lactobacillus reuteri in the intestines. This germ affects the production of the hormone oxytocin, which regulates social behavior. The lack of this bacterium in females, who were expecting offspring and then feeding, led to the fact that the mice grew with signs of autism. By adding such important microorganisms to drinking water, scientists have restored the social behavior of animals to normal – they have become more social.

Studies have been done in humans. Another group of American scientists analyzed the relationship between women’s emotional behavior and their intestinal microbiome. Observations were made on four dozen volunteers who agreed to undergo a series of trials. It turned out that those who have a large number of bacilli of the genus Bacteroides in their microflora are less likely to panic and get depressed and generally less likely to express emotions. Women, in whose microflora many Prevotella bacteria were found, on the other hand, were characterized by increased sensitivity, greater irritability and a tendency to depression.

Our minds are held hostage

The gut microbiome is better understood than other bacterial communities living in the human body. Among the inhabitants of the intestine, two types of bacteria predominate – Firmicutes and Bacteroidetes. By the way, our weight depends on their balance. With obesity, the first type of germs multiply rapidly and the second – decrease. Thus, knowing the composition of the microflora, it is possible to determine if a person is predisposed to obesity.

The bacteria that live inside us have their own food addictions. Some people like sugar, some people like fat, some people like chocolate. And if you want a french fries or some kind of cake, know that this is probably not your wish, but the “zoo” that is installed in your gastrointestinal tract. By influencing the host’s eating behavior, forcing him to consume certain foods, the microbes have at their disposal the environment in which it is most convenient for them to multiply and increase their number. In this way, they win the competition from other inhabitants of the intestinal “zoo”, who, perhaps, would like boiled spinach, cauliflower or some other set of fiber needed to get down to the esophagus. Each germ is interested in its own type of food. But the winner is the one who can take control of human eating behavior. Figuratively speaking, the invisible inhabitants of the intestines hold our body hostage (more precisely the brain that controls it) and dictate their will to it.

How do they do it? Germs affect food choices in a number of ways. They can affect the so-called reward system in the brain, change the sensitivity of the taste buds, produce substances that affect our mood or cause painful sensations until we eat the food they so desperately need.

Make them compete

If you have received the answer to the question who is to blame for your love of harmful (fried, spicy, smoked) foods and being overweight, then it is time to ask the second eternal Russian question – what to do? How can we live with the knowledge that we are being manipulated by tiny “terrorists” who have settled inside us and we can resist them if we want, for example, to lose weight?

The advice here is simple: you need to create competition for them. The more diverse the composition of the microflora, the more difficult it will be for the “bad” bacteria to understand the rest and take control of our brain. And for that you need to change your diet. Foods high in fat and simple carbohydrates (the same fast food) impoverish the microflora. Eat more vegetables, fruits, whole grains, fermented and fermented dairy products – this way, you will help your intestines to grow colonies of beneficial bacteria.

An interesting experiment was conducted by Japanese scientists. They studied how kefir, which contains beneficial lactic acid bacteria Lactobacillus casei Shirota, affects the psychological state of students during exams. It has been shown to reduce the levels of the stress hormone cortisol and increase the level of serotonin – the hormone of happiness itself. In addition, the probiotic improves sleep and reduces the occurrence of various diseases, such as colds or diarrhea. In other studies, the same strain has been found to have anti-cancer effects. Tumor-transplanted animals given these lactobacilli had 33% fewer metastases than those that did not receive them.

The main thing to remember is that we should be friends with the “zoo” that lives in our intestines. It depends on who will be for us its many inhabitants – friends or enemies. Although they should be recognized as masters of our body in any case.

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