Hot Topic October 2023: Yeast May Be Linked to IBD Inflammation

Holiday dinner table with a woman serving sweet potato fries and tomatoes on a wooden serving board. There foods are used to deter yeast and inflammation.
                                                                                                                                                                                                                    Read Time 3 minutes

Researchers writing in Nature Medicine have discovered that yeast fungi may play an important role in the development of chronic bowel inflammation associated with inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD).1 Specifically, scientists identified an increase in common gut commensal and food-derived yeasts as direct activators of altered CD4+ T cell reactions in tissue and blood samples of a small number of patients with CD compared to healthy controls. A high prevalence of anti-Saccharomyces cerevisiae antibodies (ASCAs), a marker of disease severity, has been consistently reported in the serum of patients with CD; in the present study, between 50-60% of patients exhibited ASCAs in their serum.1

Few studies to date have addressed alterations of the intestinal bacterial microbiota in IBD, and few studies have analyzed bacteria-specific CD4+ T cell responses.1 However, recent attention is being paid to the important role of individual fungal species on human health and immunopathology. Through cross-reactivity, yeast-specific T cells may contribute to the chronic inflammatory reaction; repeated contact with antigens found in multiple yeasts leads to the activation and proliferation of T-cells, triggering the immune response.1

T-cell responses to yeast fungi, including C. albicans, non-albicans Candida, and Saccharomyces species, were significantly increased in a subgroup of CD patients.1 Researchers hypothesize that this suggests that both gut-resident fungal commensals and daily dietary intake of yeasts might contribute to chronic activation of inflammatory CD4+ T cell responses in patients with CD. However, it remains unknown if yeast is the result or cause of inflammation.1

Researchers are hopeful that cross-reactive, yeast-responsive T cell receptors could be targets for the development of therapeutic interventions by antigen-specific regulatory T cell therapy or T cell-depleting strategies.1 Other treatment options include yeast elimination diets or antifungal treatment.1

Gut fungal dysbiosis has also been linked to irritable bowel syndrome (IBS)2,3 and small intestinal fungal overgrowth (SIFO),4,5 but research is in the early stages and is limited. Antifungal therapy is occasionally used to address SIFO.5 Dietary modifications may also be beneficial, but treating SIFO is complex and needs to be tailored to each patient.5-7

The identification and treatment of the underlying conditions causing the microbial imbalances in the small intestine is important. Functional medicine approaches to improve gut health may include nutritional interventions that reduce the fermentation of carbohydrates in the gut to help address bacterial and fungal overgrowth, anti-Candida diets, or an elimination diet that removes trigger foods to potentially reduce inflammation and improve symptoms. Overall, IFM’s 5R framework addresses a range of GI health issues and uses specific steps—remove, replace, re-inoculate, repair, and rebalance—to help restore a natural balance to the GI system.

Related Articles

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The Importance of Digestion & Nutrition in Chronic Disease


  1. Martini GR, Tikhonova E, Rosati E, et al. Selection of cross-reactive T cells by commensal and food-derived yeasts drives cytotoxic TH1 cell responses in Crohn’s disease. Nat Med. Published online September 25, 2023. doi:1038/s41591-023-02556-5
  2. Gu Y, Zhou G, Qin X, Huang S, Wang B, Cao H. The potential role of gut mycobiome in irritable bowel syndrome. Front Microbiol. 2019;10:1894. doi:3389/fmicb.2019.01894
  3. van Thiel I, de Jonge W, van den Wijngaard R. Fungal feelings in the irritable bowel syndrome: the intestinal mycobiome and abdominal pain. Gut Microbes. 2023;15(1):2168992. doi:1080/19490976.2023.2168992
  4. Hong G, Li Y, Yang M, et al. Gut fungal dysbiosis and altered bacterial-fungal interaction in patients with diarrhea-predominant irritable bowel syndrome: an explorative study. Neurogastroenterol Motil. 2020;32(11):e13891. doi:1111/nmo.13891
  5. Pimentel M, Saad RJ, Long MD, Rao SSC. ACG clinical guideline: small intestinal bacterial overgrowth. Am J Gastroenterol. 2020;115(2):165-178. doi:14309/ajg.0000000000000501
  6. Otaševic S, Momcilovic S, Petrovic M, Radulovic O, Stojanovic NM, Arsic-Arsenijevic V. The dietary modification and treatment of intestinal Candidaovergrowth – a pilot study. J Mycol Med. 2018;28(4):623-627. doi:1016/j.mycmed.2018.08.002
  7. Banaszak M, Górna I, Wo?niak D, Przys?awski J, Drzyma?a-Czy? S. Association between gut dysbiosis and the occurrence of SIBO, LIBO, SIFO and IMO. Microorganisms. 2023;11(3):573. doi:3390/microorganisms11030573