First AD

Second AD

A 28-year-old woman with diarrhea-predominant irritable bowel syndrome (IBS) is interested in managing her condition through diet. She asks which diet has the best evidence for the management of diarrhea-predominant IBS.

There is a causal link between food and IBS symptoms and so there has been evolving interest in evaluating the role of dietary restriction in patients with IBS. One randomized controlled trial suggested that IBS patients can identify the foods that trigger their symptoms. To date, the best evidence for dietary therapy is for the FODMAPs (

olyols) elimination diet. This diet reduces intake of poorly absorbed carbohydrates, which are fermentable in the presence of bowel bacteria.

Data for the use of a gluten-free diet in IBS is still evolving, although many of the foods withdrawn as part of a FODMAP diet contain gluten so there is some overlap between the two regimens. In a recent study, gluten was found to alter bowel barrier function; however, data on improving clinical symptoms is limited. Data for lactose restriction is largely from uncontrolled trials and overall there is insufficient data to support the use of this in IBS. Several studies have evaluated the role of fiber and demonstrated mixed results. In a meta-analysis and systematic review of supplemental fiber for the treatment of IBS, more than half of patients continued to report symptoms or had no clinical improvement with fiber.

Gastrointestinal Disorders

What to delete and what to keep, that is the IBS dietary question. 

For IBS-D, What Diet Works Best?