While we tend to hear more about SIBO causing IBS, SIFO (small intestinal fungal overgrowth) is a common issue that also causes IBS-type symptoms. Discover the most common symptoms of SIFO as well as how to diagnose and treat it.
SIBO has become a hot topic lately and is being identified as a common cause of IBS. However, SIBO may not be the only culprit. We’re now realizing that SIFO (small intestinal fungal overgrowth) is also a common issue that causes IBS-type symptoms. SIFO is a little more difficult to test for and diagnose, but it should be considered when a patient presents with symptoms of IBS and doesn’t respond to typical SIBO treatment.
Many patients exhibit symptoms of SIBO, but their breath test is negative. Or they have a positive breath test, undergo treatment, and still don’t feel better. In 2013, Dr. Satish Rao and his team published a study of 124 patients with IBS symptoms evaluated over 5 to 10 years. Researchers cultured juice from the small bowel of these patients. They found over 62% of patients had an infection in the small bowel. These are patients who are otherwise healthy. They didn’t have any other type of infection that made them sick. They just had a GI infection that was causing digestive symptoms.
As the results were broken down further, they found that 25% of the patients had SIBO, 20% of the patients had both SIBO and SIFO, and 20% had SIFO. In other words, 40% of these patients had fungal overgrowth in the small intestine.
Symptoms are very poor predictors of underlying causes because these symptoms can be related to a number of different GI conditions. However, after treatment for SIFO, people usually see a dramatic change in symptoms and feel much better.
It’s been observed that non-GI symptoms also improve, such as fatigue, joint pain, energy, and headaches.
Most common symptoms of SIFO:
There are several reasons that we’re seeing this increased rate of SIFO in our population. A few reasons are listed below.
Reasons why SIFO is an issue:
- Excessive antibiotic usage
- Long-term use of proton pump inhibitors (PPIs)
- Metabolic conditions like diabetes
- Inflammatory bowel disease (IBD)
- Dysmotility and neurological issues
- Connective tissue disorders
- Genetic predisposition
How to diagnose SIFO
Testing for SIFO is a more invasive process. A breath test for SIFO at this point is not an option because fungus doesn’t ferment like bacteria. Therefore, you wouldn’t be able to measure the level of fungus in the breath. Currently, the best test available to diagnose SIFO is a small bowel aspirate via endoscopy.
SIFO Testing Options
- Small intestine aspirate: Taking fluid from the small bowel and aspirating it. This is the gold standard.
- Stool testing: You can see Candida in stool, but this may lead to a false positive for SIFO.
- Blood antibody testing: Not a perfect test, but certainly an option and much less invasive.
Blood antibody testing is an option for Candida, but there is still a concern as to whether it’s an accurate test. The main concern with antibody testing is that it doesn’t tell you if you have an active infection. It simply suggests that you may have it or you previously had it at one point in your life. This may be more reliable than the stool test, but less accurate than the aspirate.
The future is very promising in regards to testing methods. Researchers are currently working on capsules that you can ingest that will sample small intestinal juice every 15 minutes to diagnose SIFO. This will be a very easy, minimally invasive method. In 2 to 3 years, we will have simple methods for testing. At this point, endoscopy is the best way to diagnose SIFO.
Alternatively, you have the option of treating based on symptoms. Doing a short round of antifungals is not likely to cause any negative problems. If the patient responds well, then you have pretty good confirmation that SIFO is an issue.
How to treat SIFO — Herbals vs. Pharmaceuticals
Herbal antimicrobials may be a great option because they are more broad-spectrum. They can treat both bacterial overgrowth and fungal overgrowth. The downside is that herbal agents usually require longer treatment duration. Herbs also have additional benefits. For example, oil of oregano has shown to have anti-depressant benefits. Berberine is effective at lowering and controlling blood sugar. Artemisinin has been shown to induce remission in IBD.
Herbs may be a little bit safer compared to a pharmaceutical antifungal. The main downsides to herbs are that they’re not covered by insurance, they require longer treatment duration, and there are more pills to take versus a pharmaceutical agent. You also have to be very careful with the quality of herbs and make sure you’re using a reputable brand. We highly recommend working with a skilled practitioner to help you determine the type and dosing of antimicrobials.
There are several pharmaceutical options that can be helpful in treating SIFO. When choosing an antifungal for SIFO, you need a compound that will stay intact to get to the small intestine. You want to make sure the stomach acid won’t break it up. Dr. Rao recommends fluconazole as an effective and safe option. He suggests taking one pill per day (100mg) for 3 weeks. If the patient doesn’t respond to this treatment, consider switching to itraconazole or posaconazole.
Nystatin is a popular antifungal agent. However, Dr. Rao is concerned with whether it is delivered to the small bowel. It may get broken down in the stomach, which wouldn’t make it a good option for SIFO. It’s a better option for oral and esophageal fungal infections.
For patients who have both SIBO and SIFO, Dr. Rao treats in the following way: For week 1, they get an antibiotic, such as rifaximin. In the second week, he uses both an antibiotic and an antifungal. Then weeks 3 and 4, the patient takes just the antifungal.
For patients with recurrent SIFO and/or SIBO, Dr. Rao prefers giving cyclical antibiotics and antifungals over prokinetics. For some patients, he uses both. We don’t have many great prokinetic options in the US, so he finds that cycling antibiotics and antifungals works better for his patients.
Additionally, he doesn’t use probiotics very often for his SIFO and SIBO patients because of his concern over colonizing the bacteria in the small intestine rather than the colon.
To learn more about diagnosing and treating SIFO, listen to our podcast with Dr. Satish Rao.
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Dr. Ruscio is your leading functional and integrative doctor specializing in gut related disorders such as SIBO, leaky gut, Celiac, IBS and in thyroid disorders such as hypothyroid and hyperthyroid. For more information on how to become a patient, please contact our office. Serving the San Francisco bay area and distance patients via phone and Skype.