SIFO: Understanding and Treating Small Intestinal Fungal Overgrowth
SIFO, you might have guessed it, stands for Small Intestinal Fungal Overgrowth. While the internet is going crazy about bacterial issues like SIBO (Small Intestinal Bacterial Overgrowth), understanding and addressing fungal overgrowth is equally crucial.
It is rather common to see these two types of overgrowths together, co-existing in the intestinal tract. This likely happens because factors such as weakened immunity, low stomach acid, and poor gut motility create an intestinal environment conducive to the overgrowth of opportunistic microbes (both bacteria and fungi).
For example, in one study of patients with persistent, unexplained GI symptoms, 40% had SIBO alone, 26% had SIFO alone, and 34% had a combination of both SIFO and SIBO on small-bowel aspirate.
Let's have a look at what SIFO is, how it's diagnosed, what are the treatments available, including natural remedies.
What is SIFO?
SIFO is characterised by an excessive number of fungal organisms in the small intestine, alongside gastrointestinal symptoms like bloating and abdominal pain.
While the small intestine typically has far fewer microbes (bacteria and fungi included) than the large intestine, an overgrowth of fungi can disrupt the delicate balance, leading to a range of symptoms and complications. Studies show that most SIFO cases are caused by Candida species, especially Candida albicans.
Similar to bacteria, fungi can be a normal component of the gut ecosystem, contributing to a diverse gut microbiome. The problem comes when there is an overgrowth of certain fungal species.
Symptoms of SIFO
SIFO often causes symptoms in multiple body systems, not just the gastrointestinal tract. It is common for overgrowth to appear on other sites of the body. Here are the main symptoms of SIFO:
Fatigue
Joint pain
Skin issues such as unexplained itchy rashes
Recurrent yeast infections
Yellowing and thickening of fingernails and toenails (nail fungus)
Thick white coat on the tongue (oral thrush)
Airborne allergies, including reactivity to mold
Chronic digestive discomfort (bloating, gas)
Diarrhea or constipation
As you can see, SIBO and SIFO symptoms overlap a lot.
One clinical clue that fungal overgrowth may be playing a bigger role is the presence of yeast infections (oral thrush, vaginal yeast infection, rashes in skin folds, nail fungus) alongside gut symptoms. While these infections don’t prove SIFO on their own, it can add to the overall picture and raise suspicion.
Diagnosing SIFO
Diagnosing SIFO is challenging as symptoms often overlap with other digestive disorders, as we just saw. Right now, the only formal way to diagnose SIFO in the research is through a small-bowel aspirate taken during endoscopy and cultured for fungi. This is invasive and not widely available, which is why most cases are managed clinically.
Non-invasive tests like comprehensive stool analysis, Candida antibodies, or Organic Acids Test can give indirect clues about fungal activity in the body, but they cannot confirm SIFO on their own. In practice, we look at your history, symptoms, risk factors, and lab patterns together to decide whether a trial of antifungal support is appropriate.
As mentioned above, SIFO is often found coexisting with SIBO. The two conditions can actually fuel each other, creating a complex web of symptoms. If treatments focus solely on one, the underlying issue might persist. The good news is that many herbal antimicrobials also have an anti-fungal effect as well, as opposed to antibiotics which only target bacteria.
There are a few others conditions where SIFO has a higher prevalence, mainly in people who already have chronic gut conditions, likely because these conditions often involve dysmotility, inflammation and repeated medication use. These include:
Crohn’s disease
Ulcerative Colitis
Celiac disease
Irritable Bowel Syndrome (IBS)
Treatments for SIFO
Candida overgrowth is implicated in the majority of SIFO cases. Candida is a type of yeast and a normal resident of the digestive tract, but an overgrowth can lead to systemic issues. Consequently, SIFO treatment often involves addressing Candida.
Antifungal Medications:
A course of prescription antifungal medications like fluconazole or nystatin may be recommended by your physician.
Dietary Changes:
Nutritionally, the most important step is to temporarily reduce or remove refined sugars, alcohol and ultra-processed carbohydrates, which clearly promote yeast growth. This means cutting back on:
• sweets, baked goods, sugary drinks (including fruit juices)
• white bread, pastries, and processed snacks
Moderate whole-food carbohydrates (like low glycemic fruits, root vegetables, and gluten-free whole grains) are usually better tolerated and don’t drive yeast overgrowth in the same way. We individualise this based on your symptoms and blood sugar balance, rather than removing all carbs or fruits. Know that it is only for a short period of time while you address the overgrowth.
Probiotics:
Beneficial bacteria and yeast can help restore microbial balance, supporting the immune system against fungal overgrowth. One particularly helpful probiotic yeast is Saccharomyces boulardii, which has been shown to reduce Candida colonisation and support gut immune balance. It doesn’t eradicate yeast on its own, but it can be a powerful ally in a broader protocol. You can get it from the brand Designs for Health (product is called FloraMyces) in Canada, USA and Australia.
Natural Remedies:
Certain herbs and natural compounds, such as oil of oregano, pau d’arco, horopito, berberine, caprylic and undecylenic acid, possess antifungal properties and can be incorporated as supplements. Work with a practitioner as you do not need all of these at the same time!
Lifestyle Modifications:
Stress management and regular exercise contribute to a healthier gut environment. Nothing new here!
Other Natural Remedies for SIFO
Garlic: Known for its antifungal properties, garlic can be included in the diet or taken as a supplement.
Coconut Oil: Contains caprylic acid, which has demonstrated antifungal effects.
Ginger and Turmeric: Anti-inflammatory and immune-boosting, these spices can support the body in combating fungal overgrowth.
Bone Broth: Rich in nutrients that support gut health such as collagen and glycine, bone broth can aid in the healing process. Get my healing Bone Broth recipe.
Preventing SIFO Recurrence
To properly prevent SIFO we need to understand the root causes or risk factors.
SIFO risk factors include intestinal dysmotility, low stomach acid, compromised immune function, prolonged use of PPIs, and gastrointestinal dysbiosis.
Probiotics: Maintaining a healthy balance of gut bacteria with probiotics can prevent the resurgence of fungal overgrowth.
Digestive Support: Natural strategies to enhance stomach acid and motility serves as a proactive measure, alleviating symptoms and guarding against SIFO recurrence.
Dietary Awareness: Adopting a diet low in refined sugars and processed carbohydrates, opting for lower glycemic fruits, complex carbohydrates and fermented foods (avoid with histamine intolerance) helps create an environment less conducive to fungal growth. The goal is to become an inhospitable host!
The first step in dealing with SIFO involves recognizing its symptoms and identifying it amongst other digestive disorders. With a holistic approach that includes proper diagnosis, targeted treatments, and lifestyle modifications, individuals affected by SIFO can find relief and long-term prevention.