FOS and irritable bowel syndrome: Patients demonstrated significantly higher IBS symptom severity on the low polyol diet compared to both the low FOS + GOS diet and the low FODMAP diet (p < 0.05 and p < 0.05, respectively), and no change in Birmingham IBS symptom scores was found on the low polyol diet compared to baseline (score: 19.1 ± 4.4 vs. 20.8 ± 3.9).