Fiber Supplementation Particularly Psyllium Improves Symptoms in IBS: Study
UK: Researchers have found in a new study that fiber supplementation, particularly psyllium, is associated with clinical improvement in patients with irritable bowel syndrome (IBS). Future randomized trials should evaluate individual IBS subtypes separately to better identify which patients are most likely to benefit.
The systematic review and meta-analysis, published in Gastroenterology by Heidi M. Staudacher, Department of Medicine, School of Translational Medicine, Monash University, Melbourne, Victoria, Australia, and colleagues, assessed evidence from randomized controlled trials (RCTs) examining the effectiveness of fiber supplements for IBS.
Fiber is commonly recommended for IBS management, but previous evidence syntheses are more than a decade old. The researchers searched MEDLINE, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials through April 9, 2026. Eligible studies included adults with IBS who received a fiber supplement or a suitable placebo.
The search identified 4,008 records, of which 30 RCTs involving 1,904 patients met the inclusion criteria. Wheat bran was the most frequently studied fiber, followed by psyllium, inulin-type fructans, and β-galacto-oligosaccharides (B-GOS).
Key findings were:
- Among 16 RCTs involving 1,293 patients, 52% of those receiving fiber achieved a clinical response compared with 44% receiving control treatment.
- Fiber supplementation was associated with a 21% greater likelihood of clinical response than control treatment.
- Psyllium showed a stronger benefit, increasing the likelihood of clinical response by approximately 53%.
- Across nine RCTs evaluating overall gastrointestinal symptoms, fiber supplementation did not produce a statistically significant overall improvement.
- β-galacto-oligosaccharides were associated with improvement in overall gastrointestinal symptoms.
- Wheat bran did not significantly improve clinical response or symptoms but also was not associated with worsening of outcomes.
The researchers noted that the findings support fiber supplementation, particularly psyllium, as a first-line option for IBS. However, the analysis could not reliably determine whether specific IBS subtypes, such as constipation-predominant IBS, derive greater benefit because relatively few trials reported subtype-specific outcomes.
The study had several limitations. It evaluated fiber supplements rather than fiber obtained through whole foods or complete dietary patterns. Subgroup analyses were restricted by the small number of studies evaluating individual fiber types and IBS subtypes, while only four trials specifically involved IBS with constipation. Considerable variation between studies was also observed for some outcomes, and many trials had a moderate or high risk of bias. Adverse events and treatment adherence were inconsistently reported.
Overall, the findings support continued use of fiber, particularly psyllium, in IBS management. The authors emphasized that future trials should focus on specific IBS subtypes and examine how different fibers influence symptoms and the gut microbiome to enable more individualized treatment strategies.
Reference:
Staudacher, H. M., Rucco, V., Mancell, S., Dimidi, E., & Whelan, K. (2026). Fiber Supplementation in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Gastroenterology. https://doi.org/10.1053/j.gastro.2026.07.027
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