What Is Small Intestinal Fungal Overgrowth?

candida albicans
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Small intestinal fungal overgrowth (SIFO) is the term coined to describe a theoretical condition in which atypical amounts of fungi are present in the small intestine. This overgrowth is thought to result in digestive symptoms.

Why the Focus on Fungi?

An overgrowth of fungi, particularly in the form of the yeast Candida, has been noted as a cause for infection in various areas of the body:

The fact that a fungal overgrowth can cause symptoms in the body has led some researchers to investigate whether or not an overgrowth in the small intestine might be responsible for unexplainable gastrointestinal symptoms.

Evidence for SIFO

Very little has been researched or published about the existence of a fungal overgrowth in the small intestine. The challenge in identifying a problem such as SIFO is that the role of fungi in the body is poorly understood. Fungi occur naturally in the guts of healthy individuals. At what point the presence of fungi becomes something that causes symptoms is not known at the present time.

As of now, only case reports have been published of individuals who achieved symptom relief of abdominal pain and diarrhea after taking an antifungal medication.

Purported Symptoms of SIFO

According to one report, patients who have SIFO experience symptoms that are quite similar to that of IBS:

  • Abdominal pain
  • Gas and bloating
  • Diarrhea
  • Flatulence

Who Is at Risk for SIFO?

It is theorized that SIFO is more likely to be seen in people who have:

    Others theorized to be at risk are people who are taking antibiotics or steroids, or are undergoing chemotherapy.

    How Is SIFO Diagnosed?

    SIFO is diagnosed through the taking of a sample of fluid from the small intestine during an endoscopy. The sample is then examined for its fungal content. Although a stool test can identify the presence of candida, it cannot be used to establish a symptom-causing overgrowth.

    How Is SIFO Treated?

    There are medications available which are anti-fungal. Again, research into their effectiveness in treating any possible overgrowth is almost non-existent.

    The Bottom Line

    It is important to keep in mind that Candida is a normal part of normal gut flora. Its overgrowth is perhaps pathogenic, but its presence is not.

    Any discussion of the role of fungi in the onset or maintainance of unexplained intestinal symptoms, such as those seen in IBS, can only be viewed in the most preliminary of stages. Continued research into the area will be welcomed, particularly if it can be established that addressing a fungal overgrowth does result in symptom relief.


    Erdogan, A. & Rao, S. "Small intestinal fungal overgrowth." Current Gastroenterology Reports 2015 17:16.

    Jacobs, C. & Adame, E. "Dysmotility and proton pump inhibitor use are independent risk factors for small intestinal bacterial and/or fungal overgrowth" Alimentary Pharmacology & Therapeutics 2013 37:1103-1111.

    Santelmann, H. & Howard, J. "Yeast metabolic products, yeast antigens and yeasts as possible triggers for irritable bowel syndrome" European Journal of Gastroenterology & Hepatology 2005 17:21-26.

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