Hans Selye, a hero in the study of stress, defined stress as “an acute threat to the homeostasis of an organism”. Homeostasis is internal balance. Stress leads to responses which protect the stability of the body and defend the organism’s survival. The gastrointestinal and the immune systems easily respond to stressors, and we are learning how much stress impacts gastrointestinal diseases.
Stress alters abdominal secretions, gut motility, permeability of the gut lining, sensitivity of the intestines to pain, blood flow, and even bacterial composition (microbiome) within the intestine. Stress can cause upset stomach, diarrhea, and abdominal pain, and fear and anger can easily alter gastric acid secretion. There are strong connections between the gut and the brain which mediate stress reactions.
The major chemical released by the brain and gut initiating the stress response is corticotrophin releasing factor (CRF). It coordinates the endocrine, immune, and intestinal responses to stress. CRF stimulates the pituitary gland to produce ACTH, which causes the adrenal glands to produce cortisol (the stress hormone). Diseases resulting from stress and dysregulation of the brain-gut-microbiota axis include gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), inflammatory bowel disease (IBD), inflammatory bowel syndrome (IBS), and food allergies.
PUD can be caused by Helicobacter pylori infections, nonsteroidal anti-inflammatory drugs (NSAIDs), and life stressors.
Stress aggravates GERD symptoms by relaxing the lower esophageal sphincter and increasing the sensitivity to stomach acid. Treatment of GERD includes proton pump inhibitors and stress reduction.
Stress is a risk factor in IBD, and can cause oxidative damage in colitis. Stress can lead to increased adhesion of bacteria to the intestinal wall, leading to increased oxidation. This may be altered by probiotics and by antibiotics.
IBS has a worldwide prevalence of 10-20% and is twice as common in women as in men. It is linked to stress, and symptoms are diarrhea, bloating, constipation, and abdominal pain. Most IBS patients have stable weights. Dietary exclusions can lead to improvement including the following: milk products, some carbohydrates (fructose, sorbitol), caffeine, and alcohol. Serotonergic therapies (drugs which increase serotonin) are considered important to modulate the serotonin activity in the gut. Melatonin and probiotics, laxatives, and bulking agents (such as psyllium) are useful. Alternative approaches include cognitive behavioral therapy, acupuncture, psychotherapy, hypnotherapy, and relaxation therapy. The possibility of celiac disease should lead to a blood test for serum transglutaminase-IgA.
CONCLUSION: Stress plays an important role in a variety of gastrointestinal diseases, and reduction of stress can improve these same illnesses.
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