Gut Dysbiosis and Stress

Robert Rountree, MD, describes how the microbiome has grown in importance for clinical care.

Exploration of the brain-gut connection has led to a fundamental shift from thinking of stress as exteroceptive to understanding it is essentially grown from the inside out.1 The microbiome and microbiota are now understood to be the conductors linking brain with gut, impacting the enteric nervous, autonomic, and other systems.2

Varying levels of health in the gut alter HPA axis regulation.3,4 Studies have found prebiotics effectively impacted symptoms of irritable bowel syndrome5 by changing the microflora. As a low-cost, effective stress reduction treatment, simply adding prebiotics to the diet and incorporating an exercise program can increase microbial species and metabolites having stress-protective properties.6 Even in healthy individuals, consumption of prebiotics decreases the waking cortisol response and improves emotional response.7 Prebiotics likely modulate the pathophysiology of anxiety, 8 a common comorbidity with IBS. In addition, pre- and probiotics have steadily accumulated evidence for reduction of GI symptoms in patients with IBS and other GI disorders.9

As minute examination of the gut-glia, neural regulation of epithelial cell proliferation, and enteric neurotransmitters10 continues, the understanding of stress as a disease modulator that starts with intestinal barrier function continues to increase.

Learn more about supporting the microbiome and its effect on overall health


  1. Mayer E. The neurobiology of stress and gastrointestinal disease. 2000;47(6):861-869. doi:10.1136/gut.47.6.861.
  2. Lach G, Schellekens H, Dinan TG, Cryan JF. Anxiety, depression, and the microbiome: a role for gut peptides. 2018;15(1):36-59. doi:10.1007/s13311-017-0585-0.
  3. Dinan TG, Cryan JF. Regulation of the stress response by the gut microbiota: implications for psychoneuroendocrinology. 2012;37(9):1369-1378. doi:10.1016/j.psyneuen.2012.03.007.
  4. Galland L. The gut microbiome and the brain. J Med Food. 2014;17(12):1261-1272. doi:1089/jmf.2014.7000.
  5. Silk DB, Davis A, Vulevic J, Tzortzis G, Gibson GR. Clinical trial: the effects of a trans-galactooligosaccharide prebiotic on faecal microbiota and symptoms in irritable bowel syndrome. Aliment Pharmacol Ther. 2009;29(5):508-518. doi:1111/j.1365-2036.2008.03911.x.
  6. Mika A, Rumian N, Loughridge AB, Fleshner M. Exercise and prebiotics produce stress resistance: converging impacts on stress-protective and butyrate-producing gut bacteria. Int Rev Neurobiol. 2016;131:165-191. doi:1016/bs.irn.2016.08.004.
  7. Schmidt K, Cowen PJ, Harmer CJ, Tzortzis G, Errington S, Burnet PW. Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers. Psychopharmacology (Berl). 2015;232(10):1793-1801. doi:1007/s00213-014-3810-0.
  8. Kao AC, Harty S, Burnet PW. The influence of prebiotics on neurobiology and behavior. Int Rev Neurobiol. 2016;131:21-48. doi:1016/bs.irn.2016.08.007.
  9. Ford AC, Quigley EM, Lacy BE, et al. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis. Am J Gastroenterol. 2014;109(10):1547-1561;quiz 1546, 1562. doi:1038/ajg.2014.202.
  10. Sharkey KA, Savidge TC. Reprint of: Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract. Auton Neurosci. 2014;182:70-82. doi:1016/j.autneu.2014.03.004.

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