We all know about the chicken and egg relationship. How the egg gives rise to the chicken and vice-versa but it is certainly difficult to tell which came first. The issue of the effect of the gastrointestinal tract on mental health and vice-versa is a little bit like the chicken and egg relationship as regards cause and effect. Some recent studies have pointed out the fact that there seems to be a relationship between gastrointestinal tract disorders and mental disorders. While this might seem far-fetched and outrageous, it is not so. For example, ever wonder why you lose appetite or have “butterflies in your stomach” when you are anxious or excited? Or how you have a sickening feeling in your stomach which makes you disgusted? All these with so many others will be looked into as we discuss the relationship between the gastrointestinal tract and the brain.

The gut determines, to a large extent, our emotions, mental state, and even food preferences. The health of the bowel depends on the health of the brain. At first glance these statements may seem unrealistic – but they are not. Consider the following facts:

• Recently it was discovered that the gastrointestinal tract has within its walls a large, network of nerves composed of two thin layers of millions of neurons. This is called the enteric nervous system (ENS)(Mihaela Fadgyas-Stanculete, 2014).
• The intestine has more neurons than the spinal cord – about 100 million neurons from the esophagus to the rectum- losing only to the brain in a number of neurons(Hopkins medicine, 2013).
• The bowel makes much more serotonin than the brain.More exactly, 95% of serotonin is manufactured and stored in the intestine. Serotonin is a neurotransmitter – a chemical substance made by neurons that play a vital role in the transmission and processing of information and sensory stimuli through neurons (Mayer, 2013).
• In addition to serotonin, the intestine manufactures and uses more than 30 neurotransmitters – substances involved in the transmission and processing of information by neurons in both the intestine and the brain.All these neurons and neurotransmitters are needed for the complex function that is the passage of food through the intestine – the so-called digestion (Mayer, 2013).
• The ENS helps monitor the digestion process involving, among other things, the monitoring of the pressure exerted by the food on the wall of the intestine at each moment;The coordinated movement of this food along the intestine; The progress of the digestive process; The concentration of salt, nutrients, acidity, alkalinity – all without help from the brain (Mayer, 2013).
• At the same time, these same neurons and neurotransmitters, along with those of the brain, are part of the neural network responsible for the connection between mental well-being and physical well-being and vice-versa(Mayer, 2013).

Neurotransmitters such as serotonin connect what happens in the brain to what happens in the gut and vice versa.

 

 

Relationship between intestinal disorders and mental state

Almost all sufferers of chronic diseases involving the brain, such as depression, panic, anxiety, migraine, autism, schizophrenia, etc., also suffer from problems in the digestive system to a greater or lesser degree, such as intestinal constipation (Sahar Tahbaz Hosseinzadeh, 2011 ), Irritable bowel syndrome (alternation between periods with loose bowel and periods with attached intestine), motion sickness (easy motion when moving, for example, in a simple car or bus ride), colitis, Crohn’s disease (special and potentially severe type Of inflammation in the intestine), and all kinds of mal-digestion and food intolerances. Although, there remains the challenge of understanding what the cause and effect in the relationships between intestinal and mental problems are.

 

Statistics showing relationship between intestinal disorders and mental state

In a review of studies done on the association of functional gastrointestinal disorder (FGID) and psychological disorders, it was seen that anxiety disorders were discovered to be comorbid in 38% of those with functional dyspepsia compared with it being present in 4% of the general population (Wu, 2012). Phobia, anxiety, and depression are found to strongly correlate with dyspepsia. Stress is noticed to often worsen the symptoms of irritable bowel symptoms (IBS). Also, a study showed that people with IBS showed a difference in brain morphology compared to healthy volunteers when tested using functional brain imaging. IBS has a comorbidity rate of about 25 – 44% of people with panic disorder (Mihaela Fadgyas-Stanculete, 2014). 32% of IBS subjects used in a study also had generalized anxiety disorder (Mihaela Fadgyas-Stanculete, 2014). 30% of IBS patients also have post-traumatic stress disorder. It also had a prevalence of 27 – 47.3% in people having major depressive disorder (Mihaela Fadgyas-Stanculete, 2014). These can be caused by some factors which we will now talk about.

 

Stress

Extremely strong emotions can cause from “cold in the stomach” to diarrhea and / or vomiting. How many of us do not remember at least one very important day in childhood or adolescence – it could have been a long-awaited trip, a very anticipated prize, a decisive tournament or competition finale or even a school event – where, just that day, the “unexplained” diarrhea and / or vomiting did occur?

Stress is the way we respond to an abnormal situation. It is seen as the typical reaction in a normal fight or flight scenario. For example, if you are eating with your girlfriend in a restaurant and your wife shows up (cheaters should be familiar with this) you are going to lose your appetite and thinking of the possibility of you losing half your fortune to your wife because of that scenario might just make you “poop your pants”. Well, that’s a typical stress response in relation to the release of adrenaline and cortisol in stressful situations. Your body also reacts more at the cellular level. For example, changes have been noticed in the morphology of the platelets during stressful situations to enhance clotting. Your immune system would also become hyperactive and release inflammatory mediators like cytokines and prostaglandins.

These reactions are useful in the short-term response to stress but in a scenario where stress is experienced for a longer period of time this biological response will turn out to be more harmful than helpful as we will soon explain.

Stress situations can cause an increase in gut permeability, resulting in absorption of pieces of large, incompletely digested, food material, which, once in the bloodstream, are not recognized by the body as nutrients to be used, but As foreign bodies to be attacked by the immune system, provoking reaction with the production of antibodies – an adverse reaction in this case that only serves to create an inflammatory state in our body and brain, which predisposes to a series of diseases (Deans, 2014).

 

Autoimmune response

When the body is attacked by pathogens a series of cellular and molecular events takes place as a result of the body trying to defend itself from these pathogens (harmful microbes or chemicals). One of the things that happen is that the immune systems release inflammatory mediators such as cytokine and prostaglandins. These chemicals cause swelling in some parts of the body and trap the pathogen so that the killer cells of the immune system can eliminate the pathogen. This reaction is very good in the event of an acute infection or stressful situation. But it can cause serious problems as seen in allergies when the immune system sees a harmless substance as a pathogen. In the relationship between gastrointestinal disorders and mental disorders, stressful situations can release these pain mediators and when stress occurs the prolonged release of these mediators can have an adverse effect on the gut. You can try to picture what will happen if your gut has an “allergy” for a long period of time (Deans, 2014).

Antibody reactions against poorly digested “pieces” of nutrients can have even more disastrous consequences in the event that one of these “pieces” is mistaken for the immune system to be a part of the body. In this case, antibodies begin to attack structures of the body itself (e.g. the thyroid gland, brain, joints, or any other organ or tissue) simply by confusing these structures belonging to our organism with the three-dimensional chemical structure of one of these “pieces” of  digestive material unduly present in the circulation.

This confusion and attack on structures of our own body by the antibodies is called the autoimmunity.

Autoimmune diseases are those that result from the attack on organs and tissues of the body by our own antibodies. Some examples of autoimmune diseases are celiac disease, type I diabetes, Hashimoto’s thyroiditis, rheumatoid arthritis, and brain diseases such as multiple sclerosis.

 

Intestinal flora

Just as the pathogenic organisms can potentially trigger adverse mental states, commensals can trigger a state of wellbeing. Some bacteria are said to increase the availability of neurotransmitter precursor such as tryptophan which will increase the amount of serotonin in the body which is capable of interacting with the central nervous system and intestine and hence alter mood. Another mode of action of commensals is by fighting pathogenic (bad) bacteria. This reduces the release of inflammatory chemicals by the immune system such as cytokines due to the fact that the bad guys are dying. This, in turn, reduces stress on the intestine caused by inflammation due to attack on the intestine by the cytokines. This will, in turn, improve intestinal function and by extension mental health (Deans, 2014).

 

Until just under a decade ago, changing a person’s behavior with a stool transplant would seem crazy. And it’s not something that will happen tomorrow, but animal research suggests that it may not be such a clueless idea. What is found in laboratories about the influence of the bacteria that live in our gut indicates that they do not only perform fundamental tasks for the health of our stomach but they also influence the state of the brain. These bacteria successfully transplanted experimentally in humans for combating intestinal infections and similarly, through diet and probiotic foods, including microorganisms may serve to treat psychiatric and neurological diseases (Woo Jung Lee, 2015).

Several animal experiments, especially laboratory mice raised under very controlled conditions, have shown that intestinal microorganisms can affect their behavior and modify the chemical balance of their brain. It has been shown, for example, that when feces is introduced from humans with depression into rats, these rats develop symptoms of this disease. In our species, we have also observed links between gastrointestinal diseases and psychiatric disorders such as autism, anxiety, and depression (Woo Jung Lee, 2015).

There have been studies in humans in which compares the microbiota of healthy people with others that have given disease and it was seen that modifying the intestinal flora and its functions can possibly reduce anxiety states but there is no evidence of cause and effect in more serious diseases.

There is the challenge of understanding the cause and effect relationship between intestinal and mental problems. One way to achieve this will be to perform patient interventions “through prebiotic and probiotic foods and bacteria” that modify the balance between microbes that mark the difference between disease and health. However, knowledge is still scarce to think about successfully intervening in the microbial ecosystem: “There are some publications that show that some probiotics may reduce anxiety, but they are small studies that were mostly not reproduced.” “It’s too soon to be able to make generalized recommendations because the complexity of the intestinal ecosystem is very high and it’s simplistic to think that with only one bacterium we’re going to solve the problem. We will need to think about changing the ecosystem with more integrated interventions (Woo Jung Lee, 2015).

 

Researchers around the world are beginning to identify the mechanisms by which gut bacteria, through the production of hormones and the molecules they generate by feeding, modify the chemistry of our brain (Nobuyuki Sudo, 2004 ). But for now, the knowledge about the influence of the microbiome came more through the study of correlations than through the analysis of the concrete processes that produce them. Some recent studies have shown that a greater bacterial diversity in the gut was associated with improved health. In addition, it linked this diversity to the consumption of yogurt and coffee, and indicated some drugs such as anxiolytics and antibiotics and eat too much as guilty in the fall in the microbial variety.

The complexity of the problem can be understood from the numbers on the intestinal flora. Each person has in their stomach more than one kilogram of microorganisms, most of them bacteria, of which there are approximately 1,200 different species. It will not be easy to manipulate this gear to fit our needs without producing some undesired effects. This presents its forms of problems as it is an incipient field. Furthermore, rats were used for most of the studies and replicating this in humans is difficult. There is also the question of what is considered normal or abnormal in microbial flora in humans.

 

There are already clinical trials with probiotics to treat depression that improves symptoms, but the results need to be confirmed by further studies. In addition to these products that include beneficial microbes, there are also the possibilities of using diet to repair the damaged human microbiota associated with mental illness. A good diet, like the Mediterranean, increases the diversity of the intestinal microbiota and has anti-inflammatory effects. These interventions may be used as complementary treatments in psychiatric disorders alongside the conventional drugs.

 

Diet

Slow cooking (longer on low heat) helps pre-digest foods to make the digestive process less aggressive and less costly for our gut, optimizing nutrient absorption and preserving tissue integrity Epithelial cells.

Leaving sauce grains for 24 hours (beans, brown rice, lentils, chickpeas, etc.) before cooking them slowly is an excellent way to increase the digestibility of these grains, and minimize the aggressiveness of them to our gut. Also allowing natural fermentation of bread improves wheat digestibility. Also, diets that contain intestinal flora like microbes are good for controlling intestinal problems. An example of such is yogurt. Probiotics are also good for use.

 

Genetic factors

What disease, or what undesirable manifestation of the mental state and / or behavior that a person may or may not present, can depend on the genetic predispositions that person possesses. For example, overexpression of the nerve growth factor (NGF) may lead to the development of IBS and psychiatric illnesses like anxiety and depression.

 

Some examples of relationship between mental disorder and psychological disorder

Let’s take a direct look at some diseases in trying to buttress the relationship between psychological problems and gastrointestinal problems. In a study, people with depression had a higher risk of developing peptic ulcer disease than healthy people. Also, another study reports a higher prevalence of ulcerative colitis and inflammatory bowel syndrome in those with anxiety and depression (Wu, 2012). This also holds true for patients with chronic constipation as another study shows (Sahar Tahbaz Hosseinzadeh, 2011 ).

Anxiety

The digestive process is intimately connected with the central nervous system. When anxiety is experienced over a long period of time as in anxiety disorder, there may be variations in the contractions of the gastrointestinal muscles and decrease secretions needed for digestion. Stress can cause inflammation of the gastrointestinal system, and make you more susceptible to infections.

Anxiety can cause involuntary contractions of the esophagus. In addition, it can increase heartburn causing indigestion. In stressful situations, the knot in the stomach is frequently produced by inhibiting the appetite and enhancing nauseous sensations. Already in the intestinal tract, stress can cause diarrhea and / or constipation. Therefore it can aggravate other pre-existing pathologies such as:

 

• Ulcerative colitis
• Acute diarrhea
• Chronic diarrhea
• Celiac Disease
• Diverticular disease of the colon
• Crohn’s disease
• Digestive bleeding
• Intestinal obstructions
• Gastroesophageal reflux
• Irritable bowel syndrome

 

Anxiety and poor digestion, how to control it

We must first consider some recommendations about healthy habits, so that, if necessary, psychotherapy is valued. Taking them into account can be of great help in preventing poor digestion, and overall somatizations.

1. Performingphysical activity relieves anxiety and stimulates the release of endorphins while improving the intestinal transit.
2. Practice relaxation techniques:try yoga, meditation, progressive muscle relaxation.
3. Adjustments in the diet.Avoid excess sugar, fats, caffeine, and alcohol. It is good to take, but not in excess.
4. Some drugs can have irritating effects on the digestive tract. Evaluate if in your case can negatively influence your digestion. Sometimes the anti-inflammatory drugs, if they are not accompanied by some food, can be the cause of digestive problems especially in cases of peptic ulcer.
5. Cognitive-behavioral therapy.Cognitive-behavioral therapy teaches coping skills in situations that may be causing anxiety and somatizations. In a recent study of people with irritable bowel syndrome, 70 percent noted an improvement in their symptoms after 12 weeks of cognitive behavioral therapy.

 

Irritable bowel syndrome (IBS)

This is known to affect about 11% of the global population (Mihaela Fadgyas-Stanculete, 2014). Studies have detected an increasing correlation between IBS and many mental disorders. This syndrome has been attributed to disturbances in the communication between the central nervous system and the enteric nervous system among other causes such as genetic susceptibility and altered gut movement. The symptoms of this syndrome are known to worsen with stress. Also, there has been shown to be a positive correlation and co-existence of IBS with mental disorders such as anxiety, depression, post-traumatic stress disorder, generalized anxiety amongst others. Also, brain imaging studies show a structural difference in the brains of IBS patients when compared with the brain of healthy individuals. These differences were noticed in the places responsible for pain regulation. Furthermore, in many cases where IBS co-exists with depression and some other mental disorders, there is seen to be an improvement in both IBS and the mental disorder on the administration of antidepressants especially the serotonin selective reuptake inhibitors (SSRI) (Mihaela Fadgyas-Stanculete, 2014). IBS can also be managed with laxatives and antispasmodics used as needed. Also, a cognitive behavioral therapy used to teach patients to manage anxiety and depression is very useful. Relaxation techniques are also useful in stress management (Anxiety and depression association of America, n.d.).

 

References

Anxiety and depression association of America. (n.d.). Irritable bowel syndrome(IBS). Retrieved from anxiety and depression association of America: https://www.adaa.org/understanding-anxiety/related-illnesses/irritable-bowel-syndrome-ibs

Deans, E. (2014, April 06). The Gut-Brain Connection, Mental Illness, and Disease. Retrieved from psychology today: https://www.psychologytoday.com/blog/evolutionary-psychiatry/201404/the-gut-brain-connection-mental-illness-and-disease

Hopkins medicine. (2013). The-brain-gut-connection. Retrieved from Hopkinsmedicine: www.hopkinsmedicine.org/health/healthy_aging/healthy_body/the-brain-gut-connection

Mayer, E. A. (2013). Gut feelings: the emerging biology of gut–brain communication. PMC.

Mihaela Fadgyas-Stanculete, A.-M. B.-W. (2014). The relationship between irritable bowel syndrome and psychiatric disorders: from molecular changes to clinical manifestations. Journal of Molecular Psychiatry.

Nobuyuki Sudo, Y. C.-N. (2004 ). Postnatal microbial colonization programs the hypothalamic–pituitary–adrenal system for stress response in mice. J Physiol, 263–275.

Sahar Tahbaz Hosseinzadeh, c. a. (2011 ). Psychological disorders in patients with chronic constipation. NCBI, 159–163.

Woo Jung Lee, M. L. (2015, January). Fecal Microbiota Transplantation: A Review of Emerging Indications Beyond Relapsing Clostridium difficile Toxin Colitis. Gastroenterol Hepatol (N Y), 11(1), 24–32.

Wu, J. C. (2012). Psychological Co-morbidity in Functional Gastrointestinal Disorders: Epidemiology, Mechanisms and Management. J Neurogastroenterol Motil, 18(1), 13-18. doi:10.5056/jnm.2012.18.1.13