Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies


Objective: The objective of this evidence-based medicine analysis is to determine whether or not a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), decreases overall symptoms in patients with irritable bowel syndrome (IBS).

Study Design: A systematic review including three randomized control trials (RCTs), which were conducted between the years 2014 and 2019.

Data Sources: The RCTs used were located through PubMed. All articles were selected from peer-reviewed journals that directly related to the clinical question and patient centered outcomes.

Outcome Measured: A reduction in symptoms related to IBS was measured using the IBS-Symptom Severity Scale (IBS-SSS) and the Visual Analog Scale (VAS). The IBS-SSS is based on a scale from 0-500 mm, while the VAS is scaled from 0-100 and 0-300 mm. Higher scores are correlated with more extreme IBS symptoms on both scales.

Results: Results reported by Bohn et al. revealed a decrease from baseline in the IBS-SSS of 78.0 (24%) in the low-FODMAP diet (p < 0.001) and a decrease of 66.0 (22%) in the alternative IBS diet (p <0.001). In the RCT conducted by Patcharatrakul et al., a low-FODMAP diet decreased symptoms according to the VAS by 22.7 mm (37.1%) (p < 0.001), whereas the control did not reach statistical significance (p = 0.30). Halmos et al. reported an average decrease in symptom scores by 13.2 mm (36.67%) in the low-FODMAP diet (p < 0.001), compared to an increase in symptoms on the control diet by 8.9 mm (24.72%) (p < 0.001).

Conclusions: The studies reported statistically significant findings, proving the low-FODMAP diet decreased symptoms in patients with IBS, according to the IBS-SSS and VAS. With strong evidence to support the efficacy of the low-FODMAP diet, further studies should be conducted to modify, understand, and further improve the diet.