Sunday, February 25, 2007

Irritable bowel syndrome linked to increased intestinal mast cells and intraepithelial lymphocytosis as well as stress

Our digestive tract is the largest line of defense we have to maintain against outside attack. It is vulnerable to stress, foreign food proteins and bad bacteria. Irritable bowel syndrome is reported to be the most common gastrointestinal disorder. In this month’s issue of Gut, Guilarte et al. from Barcelona Spain report finding of mildly increased intra-epithelial lymphocytes (IELs) and marked increased mast cells patients with diarrhea predominant IBS who also had higher levels of psychological stress than normal volunteers.

A stress-mast cell axis has been proposed for possible cause of IBS. Mast cells typically release chemicals in response to allergens and parasites but have also been linked to stress. Increased mast cells have been found in the large and small bowel of patients with IBS especially when a stain for tryptase, an enzyme specific for mast cells, is performed.

Mast cells can increase intestinal permeability (cause leaky gut), increase visceral sensitivity (increased pain sensation and intensity) and increase motility (contractions of the intestine). This results in diarrhea and abdominal pain. The finding of increased lymphocytes or intraepithelial lymphocytosis in the patients of this most recent study was of particular interest to me. I am seeing this very commonly in my patients who do not meet criteria for celiac disease yet respond to a gluten-free diet who have previously been labeled IBS. Sometimes I find this in small intestine biopsies and sometimes in the colon of patients. Some have had a colonoscopy in the past but no biopsies were done because the colon “looked normal”. In a recent post I discussed a study that noted IBS defining symptoms in over 50% of patients with microscopic colitis.

If you are not experiencing optimal health, consider the proposition that our digestive tract is now under constant attack and is frequently failing as a defensive barrier. Our enemies increasingly appear to be genetically modified or prepared foods and bad bacteria. The bad bacteria have taken over due to excess hygiene practices and indiscriminant use of antibiotics. Our defense must include consideration of dietary changes such as reduction or elimination of gluten, eating organic foods, and the liberal use of probiotic supplements.

Copyright © 2007, The Food Doc, LLC, All Rights Reserved.

Diarrhoea-predominant IBS patients show mast cell activation and hyperplasia in the jejunum. Guilarte, M et al. Gut February 2007; 56:203-209.

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