Infections & antibiotics
What prevents C. difficile, and what only sounds like it does
The honest state of the evidence on probiotics, fibre and food. Almost all of it is in mice. No published study has tried a change of diet in people who have the infection, and the one lever with evidence behind it is not a food at all.
3 min read3 sources
The question that follows a first episode is always a version of the same one. What can I eat, or take, so that this does not happen again? It deserves a straight answer. There is less here than anybody would like, and the useful part is not food.
Probiotics
The 2021 American College of Gastroenterology guideline recommends against the use of probiotics for the prevention of C. difficile infection in patients, regardless of antibiotic choice or use. The 2021 focused update from the American infectious diseases societies does not address probiotics at all, and makes no formal recommendation either way.
Food, and what was actually studied
A 2025 review in the Journal of Infectious Diseases gathered what is known about diet and this infection. Its own framing is the most important sentence in it. Much of the data currently originates from animal models, and significant differences exist between the human and the murine gut. There is, in the authors’ words, a paucity of studies on nutritional interventions for the prevention or treatment of the infection.
What the animal work found, stated as what it is:
- in mice, a low-fibre diet produced more severe disease, and a high-fibre diet less severe disease with faster recovery
- in mice, a high-fat and low-fibre diet produced higher mortality from the infection
- in mice, low-protein diets increased survival; the amino acid proline is a fuel the bacterium uses
- excess zinc has been associated with increased risk of recurrence and severity, and iron supplementation promoted the bacterium
- butyrate, a short-chain fatty acid, is the component most supported for a protective role — while also possibly signalling the bacterium to sporulate and increase toxin release
The lever that does have evidence
The thing that opens the door is the disruption of the gut population, and the commonest cause of that is a course of antibiotics. So the prevention with the most behind it is not something added — it is not taking an antibiotic that was never needed. That is a clinical judgement rather than a personal one, and none of it is a reason to stop or refuse an antibiotic you have been prescribed. It is a reason to know one thing. If you have inflammatory bowel disease, your risk when an antibiotic is prescribed is not the average person’s risk — and that is worth saying out loud in the room.
Where this came from
That the 2021 American College of Gastroenterology guideline recommends against the use of probiotics for the prevention of C. difficile infection regardless of antibiotic choice or use, and that the 2021 IDSA and SHEA focused update makes no formal recommendation on probiotics.
Jones J, Pradhan A, Pizzuti ME, Bland CM, Bookstaver PB, “Is Three Company or a Crowd? Comparing and Contrasting U.S. and European Clostridioides difficile Clinical Practice Guidelines”, Antibiotics, 2022;11(9):1247That much of the data on diet and this infection originates from animal models and that significant differences exist between the human and murine gut; the paucity of studies on nutritional interventions for prevention or treatment; the mouse findings on low- and high-fibre diets, high-fat and low-fibre diets, low-protein diets and proline; the associations of excess zinc with recurrence and severity and of iron supplementation with promoting the bacterium; butyrate being the component most supported for a protective role while also possibly increasing sporulation and toxin release; the hamster high-carbohydrate mortality finding; that no published studies have used broad dietary changes in human participants; and the conclusion that without a better understanding of diet in the human host we lack a nonpharmacologic approach to prevent and treat the condition.
Castro M, Silver HJ, Hazleton K, Lozupone C, Nicholson MR, “The Impact of Diet on Clostridioides difficile Infection: A Review”, The Journal of Infectious Diseases, 2025;231(6):e1010–e1018That an altered gut microbiota is what allows the bacterium to colonise and proliferate in the colon.
Seguiti C, Tettoni E, Pezzuto E, et al., “Clostridioides difficile Infection in Special Populations: Focus on Inflammatory Bowel Disease — A Narrative Review from Pathogenesis to Management”, Biomedicines, 2025;13(11):2702