Does Stress Upset Your Stomach? Disorders of the Mind That Harm the Small Intestine

Modern medicine explains the insights of the Donguibogam with remarkable precision. In particular, the concept of the gut-brain axis clearly illustrates how directly our mental state affects the small intestine. The brain and the gut are connected not merely through neural pathways, but through continuous, multifaceted communication involving hormones, neurotransmitters, the immune system, and microorganisms. When we experience stress, the brain releases stress hormones such as cortisol. These hormones directly disrupt the peristalsis of the intestine and increase intestinal mucosal permeability, which can cause leaky gut syndrome. When the intestinal mucosa loosens, undigested food particles and toxins enter the bloodstream, triggering a systemic inflammatory response that acts as another source of stress, fueling a vicious cycle. Furthermore, stress disrupts the balance between beneficial bacteria and harmful bacteria, resulting in gut dysbiosis. Considering that more than 90% of mood-regulating neurotransmitters such as serotonin and dopamine are produced in the gut, this imbalance can lead to mental health concerns such as anxiety and low mood. Chronic stress suppresses parasympathetic nerve activity and overactivates sympathetic nerves, reducing the secretion of digestive fluids and decreasing blood flow to the intestine. This lowers the capacity of the small intestine to absorb nutrients efficiently and impairs the motility of the entire gastrointestinal tract, serving as a primary cause of chronic dyspepsia, abdominal pain, diarrhea, or constipation. Gastrointestinal symptoms that arise functionally in this manner involve no actual tissue damage, yet they represent a classic example of psychosomatic disorders that cause genuine distress. It is an unfortunate cycle where stress signals from the brain impair intestinal function, and gut imbalances in turn diminish the brain's sense of well-being.