Yeast Overgrowth in Autism


All contents of this resource were created for informational purposes only and are not intended to be a substitute for professional advice, diagnosis, or treatment. Always seek the advice of your physician, therapist, or other qualified health providers with any questions or concerns you may have.

Yeast overgrowth is a medical issue common to autism that can cause sleep disturbances, sensory issues, hyperactivity, picky eating, stimming, and more.  Even more concerning, yeast overgrowth can cause physical pain.  However, when treated, symptoms can lessen or disappear altogether, significantly improving your child’s quality of life.

In this article, you will find information about yeast overgrowth, including:

  • What it is and why parents of children with autism should be aware of it
  • Symptoms
  • Causes
  • Treatment options
  • Lab testing

Yeast Overgrowth: What It is And Why Parents Should be Aware of It

First, it’s essential to understand that a healthy gastrointestinal tract contains both fungus (also known as yeast) and beneficial bacteria, in balance with each other. However, if fungus or pathogenic bacteria overgrow and outnumber the beneficial bacteria, the gut flora becomes out of balance.  We call this gut dysbiosis.

Why Parents of Children with Autism Should Be Aware of Yeast Overgrowth

While yeast overgrowth can happen to anyone, parent and clinical observations, in addition to research, suggests that it’s more common among individuals with autism.  For example, results from this 2018 study show that anti-Candida albicans antibodies were found in 36.5% of children with ASD versus only 14.3% in neurotypical kids.  This finding is noteworthy because Candida albicans is the most common type of fungus (yeast) that can overgrow and become out of balance in the GI tract.  Additionally, gastrointestinal dysfunction was found in about half of the children with autism who tested positive for anti-Candida albicans antibodies.

Symptoms of Yeast Overgrowth

Below, you will find a list of physical and behavioral symptoms that may indicate yeast overgrowth.

Behavioral Symptoms:

  • Inappropriate laughter 
  • Sleep disturbances
  • Bedwetting
  • Fatigue
  • Depression
  • “Fogginess” or poor cognition and inattentiveness
  • Hyperactivity
  • Increased self-stimulatory (stimming) behavior
  • High-pitched squealing
  • Increased sensory seeking or defensiveness
  • Climbing/jumping off things
  • Sugar cravings
  • Self-limiting foods
  • Plateauing in skills

Physical Symptoms:

  • Gastrointestinal pain 
  • Constipation
  • White tongue (also known as thrush)
  • Diaper rash 
  • Skin rashes (eczema)
  • Red ring around the anus (this can also be perianal strep)
  • Rash or cracking between the toes or joints

What Causes Yeast Overgrowth?

Now that you know what yeast overgrowth symptoms can look like, let’s talk about what can cause or contribute to it.

Sugar and Simple Carbohydrates

Yeast feeds on sugar. Therefore, limiting foods high in sugar (or foods that turn into sugar once consumed) is the first and most crucial step.  A diet high in simple carbohydrates feeds yeast. Simple carbohydrates are found naturally in foods such as fruits, milk products, pasta, white bread, processed and refined sugars such as candy, table sugar, syrups, and soft drinks.


Bacteria live in the intestinal tract, sharing space with fungus (yeast). Antibiotics kill bacteria, both good and bad, but not yeast. When using antibiotics, yeast can grow to fill in the space left by the removal of the bacteria.

Dysfunctional Immune System

Immunodeficiency can be at the root of chronic fungal infections. See more below about testing for this and supporting the immune system.  Maintaining a healthy immune system and regular, healthy bowel movements can help keep the candida in check.


Steroids bring down inflammation by decreasing the activity of the body’s immune system. Consequently, this often gives rise to fungal infections.  For example, corticosteroids and TNF inhibitors both increase a person’s chances of fungal overgrowth. To learn more, please see the CDC’s webpage that discusses how corticosteroids and TNF inhibitors increase a person’s risk of fungal overgrowth.

Treatment Options for Yeast Overgrowth

When treating yeast overgrowth, people typically focus on “killing” yeast with prescription medicines, supplements, herbs, enzymes, and diet.  However, successful treatment involves more than that.  It supports the immune system and addresses intestinal permeability and any other factors contributing to yeast overgrowth.

1. Reduce the Amount of Yeast in the GI Tract

The first step in treating yeast overgrowth is to reduce the amount of yeast in the GI tract.  Below, are brief descriptions of several nutritional tools your child’s doctor can employ to help accomplish this goal.


The best way to control the amount of yeast in the GI tract is through diet. This is because candida feeds on sugar and simple carbohydrates that convert to sugar when consumed.

Unfortunately, a gluten-free, casein-free diet is not enough to control yeast. One of the best diets for treating yeast overgrowth is the Specific Carbohydrate Diet (SCD). Following the dairy-free version of the SCD diet can starve the candida.

Beneficial Yeast

Interestingly, a beneficial yeast can be one of the most effective ways to control fungus like candida albicans. For this reason, introducing saccharomyces boulardii can be extremely beneficial.

Saccharomyces boulardii is a friendly yeast that has been used successfully to control infections such a Clostridia Difficile. However, it is extremely important to go slowly with this treatment. It can cause the pathogenic yeast to die and release toxins very quickly which can cause diarrhea followed by severe constipation. Start with a tiny sprinkle and very slowly work up based on your child’s tolerance.


Certain herbs work to help kill the fungus. However, long term use is not advised as it may compromise the beneficial bacteria.  Some examples of helpful herbs include:

  • Grapefruit Seed Extract
  • Oil of Oregano
  • Biocidin
  • Pau D’Arco

Enzymes can break open the biofilm around the yeast, making it easier to target and kill (for a more in-depth explanation on how this process works, click here).  As such, your child’s doctor may place them on one of the following enzymes:

  • Candidase by Enzymedica
  • Candex by Pure Essence
  • While not an enzyme, caprylic acid is also helpful for biofilm.
Prescription Medicaiton

There are the most commonly prescribed antifungals that treat yeast overgrowth:

  • Nystatin: a mild antifungal that stays in the GI tract.           
  • Diflucan: a more potent antifungal that addresses systemic yeast but requires regular monitoring of the liver.
Vitamins and Minerals

Also, some vitamins and minerals can help the body fight yeast.  A few examples include:

  • Biotin
  • Niacinamide
  • Selenium
Probiotics or Fermented Foods

Additionally, when taken away from antifungals, probiotics can help control the amount of yeast in the GI tract.  In fact, many doctors utilize probiotics to replenish low levels of beneficial bacteria in the gut, which then serve to keep pathogenic bacteria in check.

However, some children are very sensitive to probioticsand the new strains can overgrow quickly, causing other issues. Therefore, go slowly and watch for and reactions/results.

2. Support the Immune System

Also, successful treatment heavily relies on a well-functioning, healthy immune system.  To determine if your child’s immune system is functioning optimally, their doctor may run lab tests to check their total IgA and IgG levels (with subclasses).

If lab results indicate your child’s immune system needs support, their doctor might place them on one or more of the following:

  • Vitamin D3, Zinc, Vitamin A
  • IgG products (that have serum-derived immunoglobin concentrate)
  • DGL Licorice to balance cortisol levels and help with adrenal function.
    • Be aware that licorice can lower blood sugar levels.
    • Using the DGL form of licorice is much safer than regular licorice.
  • Camel’s milk (use caution because casein from camel’s milk can block folate receptors)
  • Colostrum (is dairy-based, so be careful if allergic)

3. Address Intestinal Permeability

Additionally, your child’s doctor will want to identify if intestinal permeability (AKA leaky gut) is causing or contributing to yeast overgrowth.

Treatment options for intestinal permeability include the following:

  • GFCF Diet: gluten is high in zonulin, which can cause intestinal permeability.
  • Supplements that help repair damage from leaky gut, including:
    • Butyrate: a short-chain fatty acid (SCFA).
    • L-Glutamine: an amino acid (use with caution as it can convert to an excitotoxin in some kids).

4. Identify and Address Other Factors That Contribute to Gut Dysbiosis

All of the above will be for naught if we do not uncover and treat other factors causing an imbalance of pathogens and good flora in the gut.  Therefore, please do not underestimate the importance of discussing the following factors with your child’s doctor.


At the risk of sounding repetitive, diet matters.  Indeed, it is the foundation of all healing.  Food such as sugar, potato chips, white bread, pasta, juice, refined sugars, and soft drinks will feed yeast. Therefore, dietary changes are essential to completely resolving a chronic yeast problem.

It is noteworthy that not all fungus is the same.  To be clear, the type of yeast that most kids struggle with is Candida albicans. Whereas the kind of yeast used to bake bread is Saccharomyces cerevisiae, which, when consumed in moderation, may help keep the gut’s population of Candida albicans in check.

Overuse of Antibiotics

Use antibiotics sparingly. As discussed above, antibiotics kill both beneficial and pathogenic bacteria, allowing the fungus to overgrow and fill in that space.  For this reason, many functional medicine doctors prescribe antifungals alongside antibiotics if they are needed.

Elevated Oxalates

Also, be aware of the relationship between oxalates and yeast. Oxalates are crystals that lead to kidney stones and other issues. When labs are run for both oxalates and yeast at the same time, it is common for results come back showing high levels of each.  To clarify, it is unknown which is the catalyst and which is the result. But, typically, if you address high oxalates, you can bring down levels of yeast overgrowth.

Examples of ways to reduce oxalate levels include:

  • Implementing a low oxalate diet.
  • Taking supplements that bind to and help usher out oxalates, such as:
    • Magnesium citrate
    • Calcium citrate
    • Biotin
    • B6
Metal Toxicity

Theoretically, heavy metals can cause the body to go into a protective mode and produce more yeast.  Accordingly, treating metal toxicity can help the body naturally overcome yeast overgrowth.

Side Effects of Yeast Treatment

When yeast dies, it releases a toxin called acetaldehyde. And, if the liver, which is responsible for eliminating toxins in the body, becomes overwhelmed, your child may experience “die-off” symptoms such as fatigue, headache, nausea, rash, diarrhea, and more.  For this reason, it is important to work with a doctor who can help you decipher the difference between a reaction to the treatment itself versus a die-off reaction.

The following can help alleviate symptoms of yeast die-off:

  • Activated charcoal
  • Alka-Seltzer Gold (not regular)
  • Drinking lots of water
  • Vitamin C or magnesium to keep stool moving
  • Interestingly, products that help combat adverse effects from dietary infractions also help reduce symptoms of yeast die-off.

Lab Testing for Yeast Overgrowth

Before we dig in to more details, it’s important to note that testing for yeast is notoriously inaccurate.  Because of this, most functional medicine doctors and parents tend to treat based on symptoms alone. Despite this, many parents still want to know about testing options, so we offer the following list of functional medicine labs to discuss with your child’s doctor.

Stool Test

One option that many functional medicine labs offer is a Comprehensive Stool Analysis (CSA). A few of the labs that provide this type of testing include:

Please note: one reason stool testing can be inaccurate is that yeast and bacteria are typically found at the beginning of the colon, yet the stool for the lab sample is collected at the end of the colon.

Organic Acid Testing (OAT)

(Urine Test)

Another option is the OAT, which detects metabolites in the urine.  While it may seem odd to test urine for an issue that’s occurring in the GI tract, sometimes it’s a better option.  In order to understand why, it’s helpful to know that yeast overgrowth in the gut alters the level of bacterial metabolites in the urine.  And, evidence of a yeast overgrowth will appear in urinary metabolite testing before it can be detected from a stool sample.

Antibody Test

(Blood Test)

This test tells you if the body is producing antibodies to yeast, thus causing an inflammatory response. Remember that GI dysfunction is found in about half of the ASD children who are positive for anti-Candida IgG.

The following is a list of labs that offer this type of testing:


In summary, let’s review some key facts about yeast overgrowth in autism:

  • A healthy gut contains both fungus, pathogenic bacteria, and beneficial bacteria.
    • As long as there is a balance between pathogenic and beneficial bacteria in the gut, there will be no problems.
  • However, if fungus and/or pathogenic bacteria overgrow and outnumber the beneficial bacteria in the gut, there is a problem.
  • Yeast overgrowth is a medical issue that is common among individuals with autism.
  • Successful treatment involves finding a good functional medicine doctor who can identify and address all factors contributing to yeast overgrowth.
  • Above all, properly addressing yeast overgrowth can make a huge difference in your child’s quality of life.

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