Diarrhea- and constipation-predominant IBS patients differ in postprandial autonomic and cortisol responses

Am J Gastroenterol. 2001 Feb;96(2):460-6. doi: 10.1111/j.1572-0241.2001.03526.x.


Objective: As the primary link between brain and gut, autonomic and endocrine dysfunction may play a role in the pathophysiology of the irritable bowel syndrome (IBS). The aim of this study was to assess autonomic, endocrine, and symptomatic responses to food intake in diarrhea-predominant and constipation-predominant IBS patients, compared to normals.

Methods: Twelve women with diarrhea-predominant or alternating IBS (IBS-D), 12 women with constipation predominant IBS (IBS-C), and 20 healthy women participated. GI symptoms, saliva cortisol concentration, heart rate, and heart rate variability were assessed at baseline and after a meal. Spectral analysis of heart rate variability was used as a measure of the sympathovagal regulation of the heart rate.

Results: Both groups of IBS patients showed a significant postprandial increase in GI symptoms. IBS-D showed a significant increase in the low frequency/high frequency band ratio and a decrease in the high frequency band power during the first postmeal period, which was significantly different, not only from controls, but also from IBS-C. IBS-D also showed a significant postprandial increase in cortisol, which was not evident in controls or IBS-C. There was a significant correlation between the vagal response and the postprandial increase in GI symptoms in IBS-D (r = 0.6, p < 0.05).

Conclusions: These findings support the notion that the IBS symptom groups are characterized by different physiological responses to visceral stimuli, and point to a role of autonomic pathways in IBS symptomatology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Autonomic Nervous System / physiology*
  • Autonomic Pathways / physiology
  • Case-Control Studies
  • Colonic Diseases, Functional / physiopathology*
  • Constipation / physiopathology*
  • Diarrhea / physiopathology*
  • Electrocardiography
  • Female
  • Heart Rate / physiology
  • Humans
  • Hydrocortisone / metabolism*
  • Postprandial Period / physiology*
  • Saliva / chemistry


  • Hydrocortisone