Looking More Closely at a Persistent Question

Virtually everyday, families that I care for are trying to ascertain the link between their GI symptoms and the foods in their diet.  Many authoritative recommendations on irritable bowel have concluded that “food allergies (symptoms caused by an immune response) are rarely the culprit in IBS patients. Most IBS patients with food-related symptoms have food sensitivities or intolerances, which are not caused by an immune response.” (From Univ Virginia Irritable Bowel Diet PDF)

Whether the process is a sensitivity or an immune-reaction, many patients are quite sensitive to certain foods and many have had improvement with a low FODMAPs diet.

A much closer look at this problem with confocal laser endomicroscopy (CLE), in a pilot study (Gastroenterol 2014; 147: 1012-20), has shown measurable changes within five minutes of a food challenge that takes place during an endoscopy.  In this study, the researchers examined 36 patients with IBS who had suspected food intolerance and 10 control patients with Barrett’s esophagus.  Then during an endoscopy, the researchers used provoking solutions of cow’s milk, wheat, yeast, or soy.  The subjects had CLE before and after the challenges. To enhance visualization of changes, subjects had fluorescein dye injected intravenously prior to examination of the duodenum.


  • In 22 of 36 patients, the challenges were considered positive.  These patients had mucosal changes including increase in intraepithelial lymphocytes, followed by disruption of the villi tips/shedding of cells, then fluorescein leakage into the lumen.
  • None of the control patients exhibited these changes.
  • 19 of 22 patients with positive challenges had a >50% reduction, after 4-weeks, in symptom score with individualized diet based on inciting antigen.


This provocative study indicates that subtle mucosal changes can occur in a number of IBS patients in a quick and direct response to food challenges.  Perhaps when we look closer with technologies like CLE we will find more answers as to why certain foods provoke symptoms in adults and children with IBS.

Related blog posts:

Also noted –web-based information on gastroparesis: