Low FODMAP Diet in Irritable Bowel Syndrome

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Researchers conducted a meta-analysis to assess the efficacy of a low FODMAP diet in patients with IBS and compared this efficacy with other dietary interventions.

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) ranked first among dietary recommendations for irritable bowel syndrome (IBS) symptom improvement, according to the results of a systemic review and meta-analysis published in Gut.

IBS is a chronic disorder of the gut-brain interaction presenting with symptoms of abdominal pain and altered stool form and regularity. Most drug treatments show limited efficacy, causing patients to turn to other treatment methods such as dietary modifications. While a low FODMAP diet if often recommended for patients with IBS, data on its efficacy vs other dietary comparators are lacking. To fill these gaps, researchers conducted a systematic review and meta-analysis to assess the efficacy of a low FODMAP diet in patients with IBS and compared this efficacy with other dietary interventions. 

Researchers analyzed the results of 13 randomized controlled trials in which a low FODMAP diet was compared to another dietary intervention in patients diagnosed with IBS. Comparison treatment arms included sham dietary recommendations, a habitual diet, a high FODMAP diet, or other dietary guidance provided by national healthcare organizations. Dietary interventions were ranked according to their P-score.

While many study results did not show significance, a low FODMAP diet ranked first in the improvement of overall IBS symptoms compared with habitual diet (P-score = 0.99). This P-value indicates the probability of a low FODMAP diet being most effective when all other inventions are compared is 99%. Low FODMAP diet was also ranked first for improvement of individual symptoms, such as abdominal pain and abdominal bloating.

The 13 studies included in the meta-analysis had an under-representation of constipation or mixed bowel habit IBS. Additionally, the trial designs focused on the benefits of FODMAP restriction, which is not appropriate for long-term nutritional needs. Additional research is needed regarding the slow reintroduction of FODMAP to a personalized level of tolerance.

Despite the limitations of the randomized controlled trials, results of this meta-analysis indicate that a low FODMAP diet may be beneficial in patients diagnosed with IBS.


Black C, Staudacher H, Ford A. Efficacy of a low FODMAP diet in irritable bowel syndrome: systemic review and network meta-analysis. Gut. Published online August 10, 2021. doi: 10.1136/gutjnl-2021-325214