Effect of Rice, Wheat, and Mung Bean Ingestion on Intestinal Gas Production and Postprandial Gastrointestinal Symptoms in Non-Constipation Irritable Bowel Syndrome Patients

The aim of this study is to evaluate the effect of rice, mung bean, and wheat noodle ingestion on intestinal gas production and postprandial gastrointestinal (GI) symptoms in non-constipation irritable bowel syndrome (IBS) patients. Methods: Twenty patients (13 F, 46 ± 11 y) underwent 8 h breath test studies and GI symptom evaluations after standard rice, wheat, or mung bean noodle meals at 8:00 a.m. in a randomized crossover study with a 1-week washout period. The same meal was ingested at 12:00 p.m. Results: The H(2) and CH(4) concentration in the breath samples were similar at baseline (rice:wheat:mung bean, H(2) = 3.6 ± 0.5:4.1 ± 0.5:4.0 ± 0.7 ppm, CH(4) = 1.3 ± 0.3:2.1 ± 0.4:1.9 ± 0.4 ppm, p > 0.05). Beginning at the fifth hour after breakfast, H(2) and CH(4) concentrations significantly increased after wheat compared to rice and mung bean (8 h AUC H(2) = 4120 ± 2622:2267 ± 1780:2356 ± 1722, AUC CH(4) = 1617 ± 1127:946 ± 664:943 ± 584 ppm-min, respectively) (p < 0.05). Bloating and satiety scores significantly increased after wheat compared to rice (p < 0.05), and increased but did not reach statistical significance compared to mung bean (p > 0.05). A higher bloating score after wheat compared to rice and mung bean was observed clearly after lunch but not after breakfast. Conclusion: Wheat ingestion produced more intestinal gas and more bloating and satiety scores compared to rice and mung bean, especially after lunch. This provides insight into the role of intestinal gas in the development of bloating symptoms in IBS.