What Is Yeast Overgrowth?


The healthy gut contains both yeast and good bacteria, in balance with each other. In many Autism Spectrum Disorder (ASD) kids, however, one or the other can be out of balance. Bacteria can overgrow, or there can be a complete lack of bacteria. Also, bad bacteria can develop and take over, rather than good bacteria, causing major problems for our children.

Bacteria live in the intestinal tract, sharing space with the yeast. Antibiotic use makes yeast worse, or can start off an unhealthy reaction causing yeast overgrowth. Antibiotics kill bacteria, both good and bad, but not yeast. When using antibiotics, the bad bacteria can take over the system and yeast can grow to fill in the space left by the removal of the bacteria.

There are many strains of yeast that live in the digestive tract including candida, which appears to be the most common. There are also several different types of "bad" bacteria, including clostridia and Citrabacter F.

Both good and bad bacteria exist in the gut. Common “good” bacteria, also called beneficial bacteria, are lactobacillus acidophilus and bifidobacterium,  And don’t panic if you see it on your test but bacteria like e-coli exist in the normal gut.

Overgrowth is made possible by a dysfunctional immune system or gastrointestinal distress. A healthy immune system and regular, healthy bowel movements should keep the Candida in check. Occasionally, these complex systems “get out of check” and overgrowth of bad bugs becomes an issue.

What is important to remember: Yeast live and feed on sugar. Limiting high sugar (or foods that turn into sugar in the gut) is the first and most important step. A diet high in carbs causes and feeds yeast.

What Does Yeast Overgrowth Look Like?

Yeast overgrowth manifests itself in two forms – behavior and physical.

Behavioral signs

  • Headaches
  • Inappropriate laughter
  • Sleep disturbances
  • Unexplained intermittent crying episodes
  • Belly aches
  • Constipation
  • Bed wetting
  • Gas pains
  • Fatigue
  • Depression
  • “Foggyness”
  • Inattention
  • Hyperactivity
  • Anger, aggression
  • Increased self-stimulatory behavior
  • High-pitched squealing
  • Increased sensory defensiveness
  • Climbing/jumping off things
  • Sugar cravings
  • Confusion
  • Lethargy
  • Inability to potty train, or loss of this skill
  • Self-limiting Foods
  • Plateauing in skills

Physical Signs

  • in the mouth, in the form of thrush
  • on the skin such as diaper rash or eczema
  • red ring around the anus
  • rash or cracking between the toes or joints
What Yeast Overgrowth Looks Like

How Do You Test For Yeast?

According to best practices, yeast levels are best measured via a stool (poop) test.

Genova Diagnostics offers a stool test called the CDSA (Comprehensive Digestive Stool Analysis)

A test such as the CDSA tells you how much yeast, what types and amounts of yeast and (both good and bad) bacteria your child has and offers you information about which pharmaceutical and homeopathic treatments might be the most effective to treat your child’s issues.

Other labs that offer a stool analysis include Doctor’s Data and Metametrix.

Urinary Organic Acid Tests (OAT) may measure levels of "fungal metabolites" (yeast waste products) in the urine. Several labs offer this test including:

Non-Specialty Lab OAT Testing

If you only have Medicaid or prefer to use the standard lab testing:

  • OAT Test  With the exception of gut pathogen metabolites, a regular quantitative organic acid test will tell about most of the other markers on the OAT.
  • For the gut pathogen metabolites, a stool culture, O&P x3, giardia, cryptosporidium will give the bacteria and parasite parts.
  • The only bad part is that no commercial test measures beneficial flora levels. One could just use a broad spectrum probiotic, though it is better to focus more on which type of probiotic is low if there is an imbalance. The CDSA from Genova Diagnostics does all this and some insurance companies will cover it. Call your insurance company to see if they will cover the test. The Genova site offers CPT codes to use when calling about coverage.
  • The equivalent of the specialty lab testing can be achieved with 2 pieces – a standard-lab OAT and stool testing.

How Do You Treat Yeast?

There are three main ways to treat yeast overgrowth – medications, homeopathic treatments and dietary changes.

Medications are only a stop-gap measure, to be used in acute cases.DIETARY CHANGES, i.e. REMOVING CARBOHYDRATES is the true treatment.

As long as you feed your child too many carbs, the yeast will keep coming back. Over and over and over. You must cut off it’s food supply, boost the immune system and heal the gut to stop it.

Medications (prescribed) include:

  • Nystatin
  • Ketoconosal
  • Sporonox
  • Amphoterican B
  • Flagyl (Metronidazole)
  • Nystatin
  • Diflucan (fluconazole)
  • Bactrim
  • Vancomycin
  • Neomycin
  • Lamisil
  • Nizoral
  • Albendazole (aka Albenza®)

Homeopathic treatments include:

  • Probiotics
  • HBOT (anecdotally)
  • Colostrum
  • ThreeLac
  • Grapefruit Seed Extract (GSE)
  • Olive leaf extract
  • Oil of oregano
  • Garlic extract
  • Pau d’Arco
  • Uva ursi
  • Biotin
  • Sugar-eating enzymes like CarbDigest or No-Fenol
  • Caprylic acid
  • Berberine
  • MCT (Medium Chain Triglycerides) oil

Note: Dosing and frequency are recommended based on the individual’s age and weight. Your doctor will prescribe the treatment according to your child's unique needs. Yeast treatments can require several treatments or reoccurring treatments to remedy the imbalance. Rarely is one yeast treatment the only requirement for keeping bacteria in balance. Dietary intervention controlling sugar and carb intake is also a crucial step in this process.

Dietary changes include:

What Is a No/Low Yeast Diet?

Yeast lives and feeds on sugar so a low/no-yeast diet would be one that limited or removed sugars, and foods that break down into simple sugars such as corn, rice, fruit. Removing juices (which are high in sugars), removing candy and all sugars is the first step. Read here for a list of sugar and carbohydrate foods that feed yeast. The SCD-CF diet is the single most effective, and highest-rated diet, used with ASD population, because it combats not only the issue of GFCFSF but also carbs, processed foods, preservatives, colors and other toxins.
For info and recipes, see www.pecanbread.com

What are Carbs

Carbohydrates are found in sugar, fruits, vegetables, dairy and grains. They both exist in either a natural or refined form. Most carbohydrates break down into glucose (a specific type of sugar). There are two types of carbohydrates: simple carbohydrates and complex carbohydrates. Both of these feed yeast.

A diet too high in carbohydrates can upset the delicate balance of your body’s blood sugar level, resulting in fluctuations in energy and mood that leave you feeling irritated and tired.

Simple vs Complex Carbs

Simple carbohydrates include sugar, juice or soda, candy and some fruits and have little to no nutritional value and therefore should be limited. Simple carbohydrates provide short bursts of energy and activity, followed by a crash of blood sugar and energy.

Simple carbohydrates are also known as sugars. Simple carbohydrates are considered “empty calories” since there are not any vitamins or minerals in sugar. Simple carbohydrates are monosaccharide (one) and disaccharide (two) carbohydrates.

Complex carbohydrates include corn, rice, potato, nuts and oats.  Complex carbohydrates provide a slower release of energy and don’t cause the same drastic blood sugar changes. Complex carbohydrates are often referred to as starch or starchy foods.

What Should I Expect To See When Treating Yeast?

Die-off (rapid dying of gut bugs, leading to excess release of toxins) of massive quantities of yeast and bacteria can be physically hard on the body. That much dead or dying stuff flying around can wreak havoc so it’s common that we see a negative reaction, before a good reaction when starting yeast treatment. This is also called a “Herkshimer” reaction, a massive die off of pathogens. There are ways to help combat this reaction and bring your child through the process with the least bad reaction.

Things that can help lessen the negative reaction:

  • Activated Charcoal capsules
  • Alka Seltzer Gold (not regular)
  • Drinking lots of water (8 oz every 2 hours minimum)
  • High doses of Vitamin C or magnesium to get them to stool the toxins out faster
  • Gut cleanout to remove the buildup* (see below)

Typically, the die off following initial treatments can be disconcerting. Witnessing a die off reaction in the first week is typically a sign that the treatment is starting to work.  Stopping the treatment regimen prior to its completion is not recommended as it can aggravate and make the condition worse. Consult your doctor for details and to address any concerns. Not every individual on a yeast treatment protocol experience “die off” or a negative reaction.

After the typical “die off” is over, usually lasting 3-7 days, most parents report that treatment improves their children's behavior and concentration –– kids seem more aware and less "foggy." Anecdotal reports claim that the frequency of inappropriate noises, teeth grinding, biting, hitting, hyperactivity, and aggressive behavior decreases. The child acts less silly and shows less inappropriate laughter, just to name a few.

Does Yeast Ever Stop Being a Problem?

Parents often have to fight yeast over and over. Here are some reasons that it returns in our children.

  • Certain treatments that we use for other issues in autism, like chelation for removal of heavy metals, or anti-virals to reduce extremely high viral markers can also exacerbate yeast.
  • A common mistake parents make when starting the GFCF diet is to substitute a lot of high-sugar, high carbohydrate foods for the gluten and casein thus causing more yeast.
  • Weak immune system – since yeast overgrowth wouldn’t be possible with a healthy immune system, it’s very important to get the immune system stabilized. Leaving the immune system weak can bring back yeast in a hurry.
  • Side effect of a prescribed supplement or a drug.
  • Toxic metals, such as mercury and chemicals, such as aspartame, MSG and others can kill friendly intestinal flora, alter immune response and allow yeast to proliferate.
  • Disorders like hormonal imbalance, celiac disease or hemochromatosis.
  • Reports back from parents indicate that as the child’s overall health improves, yeast and other bacteria imbalances become less of an issue. This process takes time and a dedicated doctor to monitor and assist in this process.

Antibiotics and Other Meds

Antibiotics and other meds (oral chelation meds, for example) can cause yeast but may be needed to address other issues so probiotics and other gut/immune boosters must be given with them in order to stem the yeast flares.

You must not give antibiotics and probiotics together at the same time, you want to space them out, or the anti- will kill the pro-.

For example, if you give the antibiotic at 7am and 4pm, you want to give the probiotics at noon and bedtime (8/9 pm).

Other immune boosters should be given with antibiotics to help the body combat whatever bacteria is invading.

The Yeast Beast Reality Check - Only YOU can stop Yeast

Yeast Reality Check

Tips For Keeping Yeast At Bay

  • Probiotics – Rotating probiotics every 3 months to include different strains.
  • Diet – makes sure your child is not getting too much sugar or too many carbs in their diet. Limit juice consumption.
  • Enzymes - Use sugar-eating enzymes.
  • Immune boosters – products like colostrum, zinc, Vitamin C, cranberry extract, Grapefruit seed extract, and others will boost the immune system.
  • Albendazole/Albenza® – using this starves sugar-eating organisms, the standard is one pill every 10 days.

More Information About Yeast Overgrowth:



2013 Webinar presentation slides on Yeast Overgrowth and ASD

Related Links:

Dietary intervention (including GFCF, SCD)

Gluten-free, casein-free, soy-free diet

SCD-CF (Specific Carbohydrate Diet)


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