The effect of stress on digestive system

08 January 2022

The gastrointestinal system and central nervous system are connected by different nerve fibers or neurons

Dr. Laden Adib Eshgh (Pharmacist): The gastrointestinal tract and central nervous system are connected by different nerve fibers or neurons. The connection between the gastrointestinal tract and the human brain is a two-way process. Improper gastrointestinal function can lead to transmission of incorrect messages to the brain; also brain’s dysfunction can lead to digestive problems.

The gastrointestinal tract contains many neurons, so the digestive system is highly irritable to stress. As you have probably experienced, the effect of anxiety on your digestive system is no less than that of unhealthy nutrition, which is why the gut is also called the second brain.

The enteric nervous system, with more than 100 million nerve cells that embedded in the lining of gastrointestinal tract from esophagus to anus, is responsible for swallowing food, secreting enzymes to break down food, absorbing nutrients, and excreting waste products.

Gut and the brain communicate through chemicals called neurotransmitters. Serotonin is one of the neurotransmitters that helps to feel excitement and vitality. Interestingly, a great part of serotonin is produced in the gut. Therefore, reducing the amount of serotonin in the body, in addition to disrupting bowel movements and causing constipation, also endangers brain health and can cause neurological problems and depression.

When stress occurs, the sympathetic nervous system (the part of the body’s autonomic nervous system that regulates functions such as heart rate, respiration, and blood pressure) secretes the stress hormone (cortisol) to fight these conditions. Cortisol causes spasms in the gastrointestinal tract, reflux exacerbations, constipation or diarrhea. In the case of constant and long-term secretion of this hormone, it can lead to diseases such as irritable bowel syndrome, intestinal inflammation, and gastrointestinal ulcers.


The effect of stress on different components of digestive system

The gastrointestinal tract consists of several parts. Each part of the gastrointestinal tract can have different problems due to stress:


  • Irritable bowel syndrome affects more than 10% of adults. Anxiety is one of the most common causes of irritable bowel syndrome, but its chronic form is often associated with depressive disorder. In this disease, the patient suffers from bloating, abdominal pain, irregular bowel movements such as diarrhea and constipation. In fact, the disease is classified into one of three main types of constipation dominant, diarrhea dominant or a combination of both.

  • Diseases such as ulcerative colitis and Crohn’s disease are also caused by inflammation in the gastrointestinal tract. The most common symptoms of these inflammatory diseases are diarrhea, abdominal pain and weight loss. In the evaluation of patients, it was found that a high percentage of them also suffer from depressive and anxiety disorders, and when these diseases recur, psychiatric symptoms also intensify in the person. Depression and anxiety can cause pain and worsen intestinal symptoms in patients.



  • Symptoms of stress on the stomach include nausea and vomiting at the time of anger or anxiety.
  • Anxiety can also lead to stomach ulcers by increasing gastric acid secretion. Various factors such as gastric bacteria (Helicobacter pylori) and the use of painkillers play a major role in the development of gastric ulcers, and the occurrence of “Generalized Anxiety Disorder (GAD)” is also closely related to gastric ulcers. The more severe the Generalized Anxiety Disorder, the greater the risk of stomach ulcers.
  • Stress can cause a sharp increase or decrease in appetite. Disruption of a person’s dietary pattern can lead to digestive problems.


  • In times of stress, people may eat much more or much less than usual. Change in dietary pattern, increased consumption of alcohol or tobacco can lead to a burning sensation or acid reflux, which can damage the esophagus in the long term.
  • Rare cases of esophageal spasm can be caused by severe stress and the symptoms may be mistaken for a heart attack.
  • Stress may also make it difficult to swallow food or increase the amount of air that enters the gastrointestinal tract while eating. In these conditions, the possibility of bloating and belching increases.

Therefore, controlling stressful conditions is very useful for improvement of gastrointestinal function. Among the stress management strategies, the following can be mentioned:

Regular exercise

Physical activity eliminates stressors and can also help reduce stress by improving sleep quality. Regular exercise is one of the best ways to manage stress and improve gastrointestinal function


Counseling and psychotherapy to replace negative thoughts with positive ones help reduce anxiety and stress.

Appropriate diet

Avoid high-fat foods, fast foods, sweets and alcohol. Also, eat in a calm, unhurried and well-lit environment.

Relaxation therapy

Performing yoga and meditation techniques, in addition to improving physical condition, increases the activity of the normal intestinal flora and reduces stress by diminishing cortisol secretion.

In daily living, the experience of stress and anxiety is inevitable. Stress can make it difficult to properly digest food and aggravate gastrointestinal diseases. So if you see signs of stress and subsequent digestive problems make sure to consult your physician.

American psychological association

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