A recent study from the UK in the Journal of Clinical Gastroenterology and Hepatology suggests that a gluten-free diet may help reduce the severity of symptoms from irritable bowel syndrome with diarrhea (IBS-D). The study followed 41 subjects suffering from IBS-D for 6-weeks while they followed a dietitian-managed, gluten-free diet. Upon completion of the study 71% of the subjects (29 of 41) reported that they had significant improvement in their symptoms.
Interestingly, none of the study participants had celiac disease but half of them tested positive for the HLA-DQ2/8 genes found in patients with CD. The response to the gluten-free diet was the same for those with the genes as it was for those without. Both groups experienced symptom reduction.
The results of this study have been duplicated in other studies where IBS sufferers are put on a low FODMAP elimination diet. FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides And Polyols) are a class of carbohydrates that are poorly absorbed in the small intestine. The FODMAP elimination diet protocal is designed to systematically identify which, if any, high FODMAP-containing foods a person is intolerant to. Breads and grains that are high in FODMAPs typically also contain gluten.
Reminder, gluten is a protein molecule, whereas FODMAPs are carbohydrate molecules.
Another resource for FODMAP information is at: http://thefodmapcentral.com/fodmap-diet-beginners-guide/