What Happens to Your Gut When You're Stressed?

Exposure to stress disrupts the communication between the brain and gut (the gut-brain axis), contributing to the development of various gastrointestinal disorders.

Studies have found inconsistent results regarding microbiome diversity but identified certain bacterial taxa related to psychological disorders.

Managing stress through lifestyle adjustments, such as diet, exercise, and mindfulness, can help improve gut health and reduce the negative effects of stress on digestion.

Stress disrupts the gut-brain axis, contributing to various gastrointestinal disorders such as gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). GERD symptoms can worsen under stress due to increased acid sensitivity and impaired lower esophageal sphincter function, making heartburn more likely. Stress weakens the gastric mucosal defense, increasing susceptibility to ulcers, particularly in individuals already exposed to Helicobacter pylori or nonsteroidal anti-inflammatory drugs (NSAIDs) (Konturek et al., 2011). 

The impact of stress on the gut extends beyond acid production and motility, the coordinated contractions and relaxations of the muscles of the GI tract necessary to move contents through the digestive system. Stress-induced inflammation can exacerbate IBD by disrupting the gut barrier, increasing oxidative stress and triggering immune responses (Konturek et al., 2011). Research suggests that acute stressors can worsen colitis symptoms and alter the gut microbiota, increasing bacterial adhesion and translocation, which may contribute to disease progression . 

IBS is one of the most common stress-related gut disorders, affecting 10-20% of the population, with women more frequently affected than men. IBS presents with symptoms such as diarrhea, constipation, bloating and abdominal pain and is often linked to gut motility. Visceral hypersensitivity is also common with IBS, where the internal organs in the chest, abdomen and pelvis become more sensitive to pain or discomfort, making them more likely to experience discomfort from normal bodily functions (Cleveland Clinic, 2022). Chronic stress and psychological factors, alongside gut microbiota disruptions, have been shown to contribute to IBS development and flare-ups (Konturek et al., 2011).

Chronic stress alters the gut microbiome by reducing bacteria like Bifidobacterium and Lactobacillus, which are typically more abundant in healthy individuals. These bacteria are important for producing metabolites like short-chain fatty acids (SCFAs), which help maintain glucose regulation, immune function and serotonin release (Warren et al., 2024). During stress, the body releases stress hormones, triggering gut bacteria to produce metabolites and toxins that can affect behavior and increase gut permeability (Madison & Kiecolt-Glaser, 2020). SCFAs, produced by bacteria such as Akkermansia, Ruminococcus, Faecalibacterium, and Lachnospiraceae, are essential for preserving the integrity of both the gut and blood-brain barriers, which chronic stress can compromise. The disruption of this microbiota-driven production of SCFAs and other metabolites, such as amino acids, can alter immune cell functions, including cytokine production, and influence inflammatory pathways in the central nervous system. This disruption contributes to gastrointestinal issues, such as IBS or IBD, and mood disorders. For instance, depression is associated with lower levels of Bacteroidetes and Faecalibacterium, and anxiety shows a decrease in overall Firmicutes and Dialister. Conversely, increased levels of Actinobacteria in depression and Enterobacteriaceae in anxiety have been reported (Paudel et al., 2022). See our previous Jona Journal blog, where we explore how stress and anxiety are connected to your gut health. We also discuss how mental health factors can impact your digestion and overall well-being.

We can look to DGBI – Disorders of gut-brain interactions to better explain our body's microbial reaction to stress. Disorders of gut-brain interaction (DGBI) are stress-sensitive, with stressful life events worsening symptoms, pain, and quality of life. Psychological comorbidities affect up to 58% of DGBI patients and increase symptom persistence. Studies show that even short-term stress, like public speaking, can increase gut permeability and raise cortisol levels. Stress also activates mast cells in the gut, which release chemicals that further break down the gut lining. In people with gut disorders like IBS, stress can make symptoms worse, increasing pain, inflammation, and discomfort. Psychological conditions such as anxiety and depression are also common in those with gut issues (Grover et al., 2025).

• Increase dietary fiber and reduce saturated fats: A Mediterranean-style diet, rich in fiber and low in saturated fats, supports a healthy gut microbiome by producing beneficial metabolites that reinforce the gut barrier and reduce inflammation (Madison et al., 2019). These dietary adjustments help modulate the gut bacteria and can lessen the inflammatory burden, improving both digestive and mental health during stressful times.
  
  
• Exercise regularly: Exercise plays a crucial role in digestive wellness by improving blood flow and regulating gut bacteria (Windsor Center for Digestive Health, 2023). Regular physical activity can help prevent digestive issues by supporting healthy gut function and reducing stress levels that can negatively impact gut health.
  
  
• Practice mindfulness and stress-reduction techniques: Engaging in mindfulness practices such as meditation or breathing exercises can help manage stress and its negative effects on the gut. These techniques lower stress hormones, improve digestion, and may help regulate eating behaviors, which contributes to healthier gut function .