Understanding gut health buzzwords
If you live with Crohn’s disease or ulcerative colitis, you have probably heard people talk about prebiotics, probiotics, and postbiotics. These terms show up on food labels, in supplement aisles, and in online articles about gut health. But what do they actually mean, and does the difference matter when you have inflammatory bowel disease (IBD)? Understanding the basics can help you make sense of the noise and have clearer conversations with your healthcare team.
What are prebiotics, probiotics, and postbiotics?
These three terms all relate to gut bacteria, but they describe different things.
Prebiotics are types of fibre that the body cannot digest. They pass through the stomach and small intestine without being broken down, reaching the large bowel where they act as food for the bacteria that live there.
Probiotics are live bacteria that you take by mouth, usually in capsules, powders, or fermented foods such as yoghurt and kefir. The idea is that these bacteria may reach the gut and contribute to the overall balance of bacteria living there.
Postbiotics are the substances that gut bacteria make when they break down fibre and other food components. These include short-chain fatty acids and other compounds that may influence the gut lining and the immune system.
Why it matters in IBD
The gut bacteria in people with Crohn’s disease or ulcerative colitis often look different from those in people without IBD. There may be less variety, and the balance between different types of bacteria may be altered. These changes may be linked to how active the inflammation is, although it is not always clear whether the changes are a cause, a result, or simply part of the picture.
Because prebiotics, probiotics, and postbiotics all interact with gut bacteria, there is interest in whether they might help support gut health in IBD. However, the evidence is mixed, and what works for one person may not work for another. None of these options replaces medical treatment.
How prebiotics work
Prebiotics include fibres found in foods such as onions, garlic, bananas, oats, and asparagus. When these fibres reach the large bowel, certain bacteria use them as fuel and produce substances such as butyrate, a short-chain fatty acid that may help support the cells lining the bowel.
For some people with IBD, eating more prebiotic fibre can cause bloating, gas, or discomfort, especially during a flare. Fibre tolerance varies widely, and what feels manageable in remission may feel difficult when inflammation is more active. Some people do better with cooked or softer sources of fibre.
Research into prebiotics in IBD is still developing. Some studies suggest potential benefits, but the evidence is not yet strong enough to recommend prebiotics routinely for everyone with Crohn’s disease or ulcerative colitis.
How probiotics work
Probiotics are live bacteria taken in the hope that they will reach the gut and influence the bacteria already living there. Different probiotic strains may have different effects, and not all probiotics are the same.
Probiotics are generally considered safe for most people, but they are not risk-free. It is always worth discussing probiotics with your doctor before starting them, especially if you are on immunosuppressant medicines.
How postbiotics work
Postbiotics are the compounds that bacteria produce after they break down food. One well-studied example is butyrate, a short-chain fatty acid that may help support the cells lining the bowel and influence how the immune system responds.
Some foods naturally contain postbiotics. For example, fermented foods such as yoghurt, kefir, and sauerkraut may contain both probiotics and postbiotics. Research is ongoing as to whether eating these foods have a meaningful effect on gut inflammation in IBD.
Practical takeaways
- Discuss prebiotics, probiotics, or postbiotics with your IBD team before making changes, especially if you are on immunosuppressant medicines.
- Tolerance for fibre and fermented foods varies widely in IBD. What works for someone else may not work for you, and what feels manageable in remission may feel uncomfortable during a flare.
- Probiotics are not all the same. If your doctor recommends a probiotic, they may suggest a specific strain or product based on the evidence for your condition.
- Postbiotics are an emerging area of research, with encouraging results in several recent trials. As with any supplement, it’s worth discussing the evidence and whether it fits your individual situation with your IBD team.
- Feeling better does not always mean inflammation has reduced. Symptoms and gut inflammation do not always match, so stay in regular contact with your healthcare team.
- These options are to be considered alongside standard treatment and should not replace your prescribed medicines.
Conclusion
Prebiotics, probiotics, and postbiotics are related but distinct. Prebiotics feed gut bacteria, probiotics are live bacteria you take by mouth, and postbiotics are the substances bacteria produce. The evidence for each in IBD is still developing, and what helps one person may not help another. If you are interested in trying any of these, a conversation with your IBD team is the best place to start. Stability in IBD comes from consistent medical care, realistic expectations, and an approach that fits your individual needs.
References
- Caio G, Lungaro L, Caputo F, et al. Nutritional treatment in Crohn’s disease. Nutrients. 2021;13(5):1628. doi:10.3390/nu13051628
- Estevinho MM, Leão Moreira P, Silva I, et al. Efficacy and safety of probiotics in IBD: an overview of systematic reviews and updated meta-analysis of randomized controlled trials. United European Gastroenterol J. 2024. doi:10.1002/ueg2.12636
- Rezac S, Kok CR, Heermann M, Hutkins R. Fermented foods as a dietary source of live organisms. Front Microbiol. 2018;9:1785. doi:10.3389/fmicb.2018.01785
- Facchin S, Calgaro M, Pandolfo M, et al. Sodium butyrate supplementation significantly improved clinical outcomes and quality of life in patients with Crohn’s disease: results from a randomised placebo-controlled study. J Crohns Colitis. 2024;18(Suppl 1):i1580-i1581. doi:10.1093/ecco-jcc/jjad212.0989
This article is intended for informational and educational purposes only. It does not constitute medical advice and should not be used as a substitute for professional medical guidance, diagnosis, or treatment.