Psyllium reduces insulin-induced colonic gas production in irritable bowel syndrome: MRI and in vitro fermentation studies

Gunn, David; Abbas, Zainab; Harris, Hannah; Major, Giles; Hoad, Caroline; Gowland, Penny; Marciani, Luca; Gill, Samantha; Warren, Fred; Rossi, Megan; Remes-Troche, Jose; Whelan, Kevin; Spiller, Robin

Abstract

Objective: Health promoting dietary fibre including inulin often triggers gastrointestinal symptoms in patients with irritable bowel syndrome (IBS), limiting their intake. Our aim was to test if co-administering psyllium with inulin would reduce gas production.

Design: A randomised, four-period, four-treatment, placebo-controlled, crossover trial in 19 patients with IBS. Subjects ingested a 500ml test drink containing either inulin 20g, psyllium 20g, inulin 20g + psyllium 20g, or dextrose 20g (placebo). Breath hydrogen was measured every 30 minutes with MRI scans hourly for 6 hours. Faecal samples from a subset of the IBS patients were tested using an in vitro fermentation model. Primary endpoint was colonic gas assessed by MRI.

Results: Colonic gas rose steadily from 0-6 hours, with inulin causing the greatest rise, median (IQR) AUC(0-360 min) 3145 (848-6502) ml.min. This was significantly reduced with inulin and psyllium co-administration to 618 (62-2345) ml.min (p=0.02), not significantly different from placebo. Colonic volumes AUC(0-360 min) were significantly larger than placebo for both inulin (p=0.002) and inulin and psyllium co-administration (p=0.005). Breath hydrogen rose significantly from 120 minutes after inulin but not psyllium; co-administration of psyllium with inulin delayed and reduced the maximum increase, AUC(0-360 min) from 7230 (3255-17910) ppm.hr to 1035 (360-4320) ppm.hr, p=0.007.

Fermentation in vitro produced more gas with inulin than psyllium. Combining psyllium with inulin did not reduce gas production.
Conclusions: Psyllium reduced inulin-related gas production in IBS patients but does not directly inhibit fermentation. Whether co-administration with psyllium increases the tolerability of prebiotics in IBS warrants further study.

Citation

Gunn, D., Abbas, Z., Harris, H., Major, G., Hoad, C., Gowland, P., …Spiller, R. (2022). Psyllium reduces insulin-induced colonic gas production in irritable bowel syndrome: MRI and in vitro fermentation studies. Gut, 71(5), 919-927. https://doi.org/10.1136/gutjnl-2021-324784

• Journal Article Type: Article
• Acceptance Date: Jul 8, 2021
• Online Publication Date: Aug 5, 2021
• Publication Date: 2022-05
• Deposit Date: Jul 15, 2021
• Publicly Available Date: Aug 5, 2021
• Journal: Gut
• Print ISSN: 0017-5749
• Electronic ISSN: 1468-3288
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 71
• Issue: 5
• Pages: 919-927
• DOI: https://doi.org/10.1136/gutjnl-2021-324784
• Keywords: Gastroenterology
• Public URL: https://nottingham-repository.worktribe.com/output/5787008
• Publisher URL: https://gut.bmj.com/content/early/2021/08/04/gutjnl-2021-324784