Treatments · Supplements
Soluble fiber (psyllium)
What ACG 2021, BSG 2021 and NICE say about soluble fiber (psyllium) for IBS, with the studies, trials, news, and stories we have tagged to it.
What the guidelines say
| Body | Position | Strength and evidence | Source |
|---|---|---|---|
| ACG 2021 | Suggests that soluble, but not insoluble, fiber be used to treat global IBS symptoms. | Strong recommendationModerate quality of evidence | PubMed |
| BSG 2021 | Soluble fibre such as ispaghula is an effective treatment for global symptoms and abdominal pain in IBS, but not insoluble fibre such as wheat bran; it should be commenced at a low dose (3-4 g/day) and built up gradually to avoid bloating. | Strong recommendationModerate quality of evidence | PubMed |
| NICE | Review fibre intake and adjust (usually reduce) it while monitoring symptoms; discourage insoluble fibre such as bran; if an increase in dietary fibre is advised, it should be soluble fibre such as ispaghula powder or foods high in soluble fibre such as oats. | Not graded | Source |
Soluble fibre dissolves in water to form a gel. Psyllium (ispaghula husk) is the form most studied in IBS; oats and linseed are dietary sources. The gel is thought to normalise stool consistency in both directions, softening hard stool and firming loose stool. Insoluble fibre such as wheat bran adds bulk but is fermented differently and has not shown benefit in IBS trials PMID 25070054.
The key pooled evidence is a 2014 meta-analysis of 14 randomised trials (906 patients): fibre overall reduced the risk of remaining symptomatic (relative risk 0.86, number needed to treat 10), but the benefit was confined to soluble fibre (relative risk 0.83, number needed to treat 7), with no effect from bran (relative risk 0.90) and no evidence of harm from bran either PMID 25070054. In a 2020 network meta-analysis that compared soluble fibre, antispasmodics, peppermint oil, and gut-brain neuromodulators, no active treatment was significantly better than another for global symptoms after direct or indirect comparison, and only 13 of 51 trials were at low risk of bias PMID 31859183.
Points clinicians commonly raise: the three guidelines agree on the soluble-versus-insoluble distinction, which is unusual in IBS PMID 33315591 PMID 33903147; the BSG advises starting at 3 to 4 g a day and increasing gradually because bloating is the usual reason people stop PMID 33903147; psyllium needs to be taken with adequate fluid; and the effect in trials is modest, so it is generally framed as a first step rather than a complete plan.
Talk to a clinician before starting or stopping anything.
References
- 1Lacy BE, Pimentel M, Brenner DM, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021. PMID 33315591
- 2Vasant DH, Paine PA, Black CJ, et al. British Society of Gastroenterology guidelines on the management of irritable bowel syndrome. Gut. 2021. PMID 33903147
TreatIBS is an informational site and does not provide medical advice. The research summarized here may not apply to your situation. Talk with a clinician before starting, stopping, or changing any treatment.
Studies
Recent PubMed entries tagged to Soluble fiber.
Trials
Registered interventional studies tagged to this approach.
Psyllium in Pediatric IBS
Psyllium (0.7 g/year of age per day), Psyllium (0.5 g/year of age per day), Placebo
News
Headlines that mention this approach, linked to the original.
Fiber Supplementation in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Fiber supplements lead to clinical response in irritable bowel syndrome, with psyllium most effective. More research is needed to understand which fibers might…
Rice bran compound may help ease irritable bowel symptoms
A compound in rice bran may help calm an overactive gut by reducing the calcium signals that cause intestinal muscles to contract. Ferulic acid suppressed…
Stories
Public accounts from people who tried it, labeled as individual experience.
Caitlyn Mcadam: IBS-C diagnosed in sixth form, laxatives, a hospital dietitian and yoga
Reported that daily porridge, eating three regular meals slowly, limiting caffeine, takeaways and solid chocolate, and starting evening yoga noticeably reduced her bloating and pain in the month after a bad Christmas; she still turns to laxatives after long stretches without a bowel movement.
Kira With IBS on daily psyllium (Metamucil) after 20 years of IBS
Reported that a nightly teaspoon of psyllium keeps her stools more consistent and eases her night-time nausea, and that temporarily raising the dose settles bad spells; side effects she noted were hunger, frequent urination and harder stools if she drinks too little water.
Critiques
Single-study critiques that cover this approach.
No critiques on Soluble fiber yet.