Irritable Bowel syndrome

Individuals with gluten sensitivity have an increased prevalence of fulfilling the Rome III criteria for IBS.

It is not uncommon for patients with IBS to report improvement in clinical symptoms when gluten intake is restricted.

A series of studies have investigated the response to gluten in patients with IBS in whom celiac disease has been excluded. Wahnschaffe and colleagues noted an improvement in patient-reported outcomes following institution of a gluten-free diet, including a decrease in the frequency of bowel movements, in patients with diarrhea-predominant IBS in whom celiac disease had been excluded.

Biesiekierski and colleagues also studied patients with IBS who were proven not to have celiac disease and whose symptoms were under control on a gluten-free diet. Participants in this randomized trial were asked to eat a muffin containing gluten or a placebo of identical taste and texture. They found that symptoms were present in 68% of those ingesting gluten compared with 40% of those receiving a gluten-free product.

Vazquez-Roque and colleague studied 45 patients with diarrhea-predominant IBS who had no history of gluten avoidance. They were randomly assigned to receive either a gluten-free or a regular diet. Those on the gluten-containing diet had more frequent bowel movements.

Di Sabatino and colleagues administered small amounts of purified gluten (4.4 g per day, equivalent to the amount present in two slices of bread) to 61 adults without celiac disease or wheat allergy who believed that ingestion of gluten-containing food was the cause of their intestinal and extraintestinal symptoms. In this crossover trial, the severity of overall intestinal—as well as extraintestinal—symptoms increased significantly during 1 week of intake of small amounts of gluten, compared with placebo. However, most patients showed no significant difference and the positive result was driven by a large effect of gluten in three patients.