Gut Health & Depression

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The human intestine is inhabited by the organisms that need the substances of the central nervous system. American scientists from the Northeastern University of Boston have detected the bacteria in the human intestine that use the substances produced by the brain.

Most people do not understand that the intestine is, in the direct meaning of the word, your second brain, which is really capable of exerting a significant influence on your:

  • Mind
  • Mood
  • Behavior

Modern psychiatry still erroneously claims that psychological problems, such as depression, are caused by a disruption in the balance of chemicals in the brain. Researchers keep finding evidence that depression and various behavioral problems are in fact associated with the violation of the balance of intestinal bacteria!

Sterile mice are more prone to high-risk behavior

According to the study published last month in the Neurohistroenterology and Motorics journal, the behavior of mice with a deficiency of intestinal bacteria differs from that of normal mice – the former behave in a way that is more likely to be called “high-risk behavior.” This altered behavior was accompanied by neurochemical changes in the brain of mice.

According to the authors, the microflora (intestinal flora) plays a role in the connection between the intestine and the brain, and the acquisition of the intestinal microflora in the period immediately after birth has a determining effect on the development and functions of the gastrointestinal tract, the immune, neuroendocrine and metabolic systems. For example, the presence of intestinal microflora regulates the control point of the hypothalamic-pituitary-adrenal axis.

Serotonin neurotransmitter activates the hypothalamic-pituitary-adrenal axis, stimulating certain receptors of serotonin in the brain. In addition, some neurotransmitters, such as serotonin, are also present in the intestine. In fact, the highest concentration of serotonin, which is responsible for controlling mood, depression, and aggression, is in the intestine rather than in the brain!

So it really is worth feeding your intestinal flora to optimize the function of serotonin because it can significantly affect your mood, psychological health, and behavior.

The presence or absence of the usual intestinal microflora affects the development of behavior.

This conclusion is supported by another recent animal study, which also found that intestinal bacteria affect early brain development and mammalian behavior. But that’s not all. It was found that the absence or presence of intestinal microorganisms in infancy forever changes gene expression.

With the help of gene profiling, scientists managed to find out that the absence of intestinal bacteria alters the genes and the signaling pathways associated with learning, memory and the management of motor functions. This suggests that intestinal bacteria are closely associated with early brain development and subsequent behavior.

These behavioral changes could be reversed during the early age when the mice were exposed to normal microorganisms. But as soon as sterile mice reached adulthood, colonization by bacteria no longer affected their behavior.

According to Dr. Rochellys Diaz Heijtz, lead author of the study, these data indicate a critical period at an early age, during which intestinal microorganisms affect the brain and alter behavior in later life.

Similarly, it has been established that probiotics affect the activity of hundreds of genes, helping their expression in a positive way that fights diseases.

The connection of the intestine and the brain

Taking into consideration the fact that the connection between the intestine and the brain is recognized as the basic principle of physiology and medicine and that there is plenty of evidence of how the gastrointestinal tract is involved in various neurological diseases, it is not difficult to see that the balance of intestinal bacteria plays an important role in psychology and behavior.

Keeping this in mind, it is quite obvious that feeding the intestinal flora is a matter of utmost importance from the cradle to the grave. In the most direct sense of the word, we have two brains: one inside the skull and the other in the intestine, and each of them needs its own vital nutrition.

It is interesting to note that these two organs are made of the same type of tissue. During the development of the fetus, one part of it turns into the central nervous system, and the other evolves into the enteral nervous system. These two systems are connected by a vagus nerve – the tenth cranial nerve that runs from the brainstem down to the abdominal cavity.

This is what connects the two brains and explains such phenomenon as the feeling of butterflies in the stomach when you are nervous.

Your intestines and brain work in tandem, influencing each other. That’s why intestinal health can have such a profound effect on your mental health and vice versa.

Now it is obvious that your diet is closely related to your mental health. In addition, it is easy to imagine how the lack of nutrition can negatively affect your mood and your behavior afterward.

Aren’t we too disinfected for the peace of mind?

Another study published last year in the Archives of General Psychiatry examined the evidence that mental problems may be caused by the absence of natural microorganisms in soil, food, and the intestine.

Such a connection was really found.

The incidence of depression among young people is steadily increasing. It even exceeds the level of depression in older people, and one of the reasons for this is the lack of exposure to bacteria, both outside and inside the body.

To put it in plain words, modern society may be too disinfected and pasteurized for its own good.

In most cultures, fermented milk products were the usual core products, but the modern food industry, in an effort to kill ALL the bacteria for safety, eradicated most of these products. Of course, traditionally fermented products, such as natto or kefir, can still be found on the market, but they are no longer part of the diet as they used to be. Most people who first try them in adulthood do not find these products tasty.

When you deprive your children of all these bacteria, their immune system – the primary defense against inflammation, in fact, becomes weaker rather than stronger. The higher level of inflammation is a sign of not only heart disease and diabetes but also depression.

The authors explain this in the following way:

Significant evidence suggests that the accompanying evolution processes have given various microorganisms (often called “old friends”) a task to teach the human immune system to survive a wide spectrum of potentially stimulating inflammation, but not life-threatening stimuli.

In the modern world, such immunity preparation saves vulnerable people from the risk of a huge number of unjustified inflammatory reactions to harmless environmental antigens (which lead to asthma), safe food components and conditionally pathogenic microorganisms in the intestine (which lead to inflammatory bowel diseases), as well as self-antigens (which lead to a variety of autoimmune diseases).

Loss of the influence of these old friends can contribute to major depression, increasing the background level of depressogenic cytokines, and predispose vulnerable people in industrially developed societies to manifest unreasonably aggressive inflammatory reactions to psychosocial stressors, which again leads to an increase in depression.

Studies conducted all over the world link problems with the intestines to brain disorders.

Brain disorders can take many forms, one of which is autism. In this particular area, you can again find convincing evidence of the connection between the brain and intestinal health.

Gluten intolerance is often a sign of autism, and a strict gluten-free diet improves the condition of many autistic children. A lot of children with autism are helped by taking probiotics in the form of fermented food products or additives with probiotics.

Dr. Andrew Wakefield is one of many scientists who researched the relationship between developmental disorders and bowel diseases. He published about 130-140 reviewed papers, exploring the mechanism and causes of inflammatory bowel diseases, and extensively studied the connection of the brain and intestines in the context of children with developmental disorders, such as autism.

Researchers from around the world have conducted a large number of repeated studies that have confirmed the peculiar connection between brain disorders, such as autism, and the gastrointestinal dysfunction.

Other useful properties of probiotics

The body contains about 100 trillion bacteria – 10 times more than the cells. The ideal ratio of bacteria in the intestine is 85% “useful” and 15% “harmful” bacteria.

In addition to the psychological consequences described above, a healthy ratio of beneficial and harmful bacteria is important for such aspects as:

  • Protection against the excessive growth of other microorganisms that can cause diseases
    Digestion of food and the absorption of nutrients
  • Digestion and assimilation of certain carbohydrates
  • Production of vitamins, minerals, absorption, and elimination of toxins
  • Prevention of allergies
  • The signs of the excess of harmful bacteria in the intestine are flatulence and bloating, fatigue, craving for sugar, nausea, headaches, constipation or diarrhea.

What prevents useful intestinal bacteria?

Intestinal bacteria do not live in the bladder – they are an active and integral part of your body, and therefore they are vulnerable to your lifestyle. If, for example, you eat a lot of processed foods, there is a threat to the intestinal bacteria because such products destroy healthy microflora, feeding harmful bacteria and yeast.

The intestinal bacteria are also very sensitive to:

  • antibiotics
  • chlorinated water
  • antibacterial soap
  • agricultural chemicals
  • pollution

Because of these factors, which almost everyone is exposed to at least from time to time, it is a good idea to “reseed” the intestines with beneficial bacteria, taking high-quality additives with probiotics or consuming fermented foods.

Tips for optimizing the intestinal flora

It is important to understand that somewhere around 80 percent of the immune system is actually in the intestine, so it is necessary to regularly reseed the intestines with beneficial bacteria.

In addition, if you consider that the intestine is your second brain and the location of the immune system, it is not difficult to see that intestinal health affects the brain function, psyche and behavior. They are all interrelated and interdependent in various ways, some of which are discussed above.

For this purpose, the recommendations for optimizing the intestinal flora are given below.

Fermented (soured milk) products are still the best way for the optimal health of your digestive system is to use the traditionally cooked unpasteurized versions. Useful dishes include lassi (an Indian yogurt drink, which is traditionally taken before dinner), sour milk or kefir, various sauerkraut vegetables, such as cabbage, turnips, eggplants, cucumbers, onions, zucchini, and carrots, as well as natto (fermented soybeans).

If you regularly eat such unpasteurized fermented foods (pasteurization kills natural probiotics), the beneficial flora of the intestine will thrive.

Additives with probiotics. Although we are not advocates of taking many supplements (since we believe that the nutrients should come mainly from food), probiotics are certainly an exception.

If you do not eat fermented foods, you are strongly recommended to take high-quality supplements with probiotics.