The researchers challenged and re-challenged people with IBS in whom celiac disease had been excluded whose symptoms were controlled on a gluten-free diet. These individuals were randomized to gluten-free diet with daily supplements of muffins and bread with a standard amount of gluten added or not added. Both the patients and the investigators were blinded to whether they were getting gluten containing muffins or bread and taste tests were done confirming that the two forms were indistinguishable. Symptoms were tracked by analogue scale. Patients were significantly worse within one week of gluten ingestion and had significantly worse bloating, abdominal pain, altered bowel pattern and fatigue.
In an editorial following this article in the March 2011 issue of the American Journal of Gastroenterology, Dr. Elena Verdu, MD, PhD., states "...gluten may be one of a multitude of triggers of low-grade inflammation and/or gut dysfunction in IBS" and "Gluten sensitivity could be raised as a possible cause of functional symptoms in patients with a positive anti-gliadin antibodies, and gluten restriction advised as a therapeutic trial."
There is accumulating evidence that IBS does in fact involve low-grade inflammation and immune activation. Mast cells have been implicated for several years but only recently has there been studies showing increased activated mast cells present in the duodenum, ileum and/or colon of individuals with IBS symptoms. The trigger in these individuals is believed to be some type of immune stimulating event such as an intestinal infection (hence the post-infectious form of IBS) or proteins in the gut such as foods and/or microbes that are sensed by the body as being foreign attackers. The role of microbes is getting a lot of scientific and research attention whereas food proteins as a cause of IBS, has generally been doubted by US scientists or ignored until just recently.
Quoting research findings of Wahnshaffe et al, Dr. Verdu points out the presence of genetic markers for celiac disease predicted responsiveness to a gluten-free diet in people with IBS. This is consistent with my clinical research findings of positive responsiveness to a glutenfree diet in individuals with at risk genetics (HLA DQ2 and/or DQ8) without proven celiac disease, though many had positive AGA tests.
The role of mast cells and gluten in IBS is something I will continue to explore as I have now accumulated almost 400 patients with MIBD, many of whom have had celiac genetic testing and tried a gluten-free diet. Stay tuned for more information on mast cells in gastrointestinal disease.
Gluten Causes Gastrointestinal Symptoms in Subjects Without Celiac Disease: A Double Blind Randomized Placebo-Controlled Trial. Biesiekierski, J. et al. Am J Gastro 2011;106:5080514.
Can Gluten Contribute to Irritable Bowel Syndrome? Verdu, E. Am J Gastro 2011;106516-518.
Mast Cells in Gastrointestinal Disease. Ramsay D., et al. Gastro and Hepatol 2010;6(12):772-777.
Mastocytic Inflammatory Bowel Disease ( MIBD ) : Increased Prevalence of Celiac - Related HLA DQ Genetics, CBir1 and Antigliadin Antibodies Associated With Response to Gluten Free Diet. Lewey, S. Am J Gastroenterol 2009; 104:S431-S484
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