A study, published in the American Journal of Gastroenterology, analyzed exclusion diets and whether they impacted irritable bowel syndrome symptoms.
Researchers reviewed literature from the Medline, Embase, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews databases. They analyzed nine randomized controlled trials of IBS-exclusion diets. Their study evaluated exclusion diets against alternative or usual diets.
Here's what the study found:
1. Two trials featured 111 patients who responded positively to a gluten-free diet. The patients either continued the diet or received a diet that was "spiked" with gluten.
2. In both trials, gluten-free diets failed to reduce global symptoms at a statistically significant level.
3. Seven trials compared diets with low fermentable oligo-, di- and monosaccharides and polyols foods. About 397 participants were involved.
4. A low FODMAP diet reduced global symptoms when compared to controls.
5. The trials that compared low FODMAP diets with control diets had the least heterogeneity between studies, but also the least magnitude of effect. Researchers gave the data a "very low" grade.
Researchers concluded, "There is insufficient evidence to recommend a [gluten-free diet] to reduce IBS symptoms. There is very low-quality evidence that a low FODMAP diet is effective in reducing symptoms in IBS patients."