BMJ

Irritable bowel syndrome diets, supplements, and microbiome therapies

January 6, 2025

Summary. Fiber is a mainstay of IBS treatment, and there’s general support for the low FODMAP diet. Complementary and integrative health therapies including peppermint oil and traditional herbal based interventions are gaining acceptance, with mixed recommendations in guidelines. Microbiome-based therapies are similar, with overall limited evidence and mixed support from guidelines for probiotic use and consensus that fecal microbiota transplant isn’t currently recommended for IBS treatment.

Diet

• Fiber. In dietary and supplement form, fiber is a mainstay of treatment for IBS and is recommended in multiple guidelines as front-line therapy for global symptom improvement as defined by FDA as a primary outcome of IBS therapeutics. The most often recommended soluble fiber for IBS is psyllium.
• Low FODMAP diet. International guidelines generally support use of the low FODMAP diet with guidance from a registered dietitian. A 2022 systematic review of 13 RCTs showed superiority of low FODMAP diet to habitual diet and all other dietary interventions.
• Kiwifruit. Although evidence to support the use of kiwifruit as a treatment modality is limited, the intervention is relatively safe and accessible. However, it is important to note that some people might be allergic to kiwifruit or develop an oral allergy syndrome owing to cross-reaction in those allergic to birch tree pollen.
• Mediterranean diet. This diet has many overall benefits but needs more evidence for use specifically in IBS.

Herbs & supplements

• Glutamine requires further study but might have an adjunctive role in certain patients.
• Vitamin D. Given the potential risks and conflicting results in trials, vitamin D supplementation can be considered for short-term trial treatment with careful monitoring for toxicities.
• Peppermint oil has antispasmodic properties that have been well studied for the treatment of IBS and is suggested for relief of global IBS symptoms as a conditional recommendation in ACG. A recent systematic review and meta-analysis that included 10 RCTs (n=1,030) found peppermint oil more efficacious than placebo for global IBS symptoms and abdominal pain. The peppermint oil group experienced more adverse events, which were predominantly mild symptoms of reflux, dyspepsia, and flatulence.
• Cannabis. Despite increased access and patient interest, the risks of cannabis-based treatments for IBS outweigh benefits based on current trials. Their use is not recommended in the Joint Consensus of Italian Societies guidelines.

Microbiome-based therapies

• Probiotics. A systematic review and meta-analysis of 53 RCTs (n=5,545) found that probiotics had beneficial effects on global IBS symptoms and abdominal pain. However, the 2020 AGA guideline notes statistically significant heterogeneity in study design, outcome, and probiotics used, and evidence for publication bias, leading to no recommendation outside clinical trials.
• Prebiotics. The roles of prebiotics and probiotics in IBS is currently unclear.
• Fecal microbiota transplant for IBS has not shown statistically significant benefit in IBS and carries risk of serious adverse events including infection.

Source:

Wang XJ, et al. (2024, December 16). BMJ. Non-pharmaceutical treatments for irritable bowel syndrome. https://pubmed.ncbi.nlm.nih.gov/39681399/