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Evidence Based

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Do You Need a Candida Overgrowth Test?

Written by Dr. Michael Ruscio, DC on March 12, 2022

Written by Dr. Michael Ruscio, DC on March 12, 2022 — Reviewed by Aimee Gallo

Validity and Use of Candida Overgrowth Tests

• Common Symptoms of Candida Overgrowth|
• Common Causes of Candida Overgrowth|
• Types of Testing|
• Debunking Candida Overgrowth|
• Treating Candida Overgrowth|
• Simple Ways to Decrease Candida|

In the past, candida overgrowth may have been over-diagnosed in the natural health field, and suspected for every chronic health issue from diarrhea to fatigue. Now we have more research and a better understanding of when candida overgrowth might be a true contributing factor to your symptoms, and when to get a candida overgrowth test. 

So how do candida tests work, what do they really tell you, and when should you consider getting one? We’ll explore all of these questions and more. 

Most Common Symptoms of Candida Overgrowth

You may have read that candida can cause everything from headaches, constipation, sinus infections, allergies, toenail fungus, and joint pain to brain fog and mood swings. However, those aren’t the most common symptoms of yeast overgrowth. The most common symptoms of candida overgrowth are:  

• Genital or vaginal itching 
• Genital or vaginal discharge
• Burning during urination
• Sugar cravings
• Whitish/yellowish plaque on the tongue
• Skin rashes
• Diarrhea 

In fact, there’s no evidence to show that candida overgrowth can cause all of the other symptoms we’ve been told it can, such as brain fog, athlete’s foot, and joint pain 1 2 3. That doesn’t necessarily mean they can’t be related, but if you’re experiencing these symptoms absent the more common and proven candida overgrowth symptoms, it’s best to look into more likely causes (such as a gut health imbalance) first.

At our clinic, we seek to know the patient’s history and symptoms first before using most kinds of tests, including in the case of candida overgrowth.

Common Causes of Candida Overgrowth

C. albicans (or candida, a type of yeast) colonizes the digestive tract of healthy people, but it can develop into an opportunistic infection. This is why we look closely at medical history, as it can give us clues to whether a candida overgrowth might be an issue.

Some of the most common contributing factors to candida overgrowth are 4:

• Compromised immune systems (such as HIV or cancer patients) 
• Corticosteroid use 
• Antibiotic use
• Undergoing chemotherapy 
• Diabetes 
• Pregnancy
• Taking oral contraceptives

After looking at medical history and current symptoms, candida overgrowth testing might be an option. Let’s take a look at those tests and what the research says about them. 

Types of Candida Overgrowth Tests

There are three main types of tests for candidiasis (fungal infection caused by candida): oral or genital samples, blood tests, and stool tests. 

Sample Under Microscope

In most cases, presenting with symptoms such as a white film on the tongue, genital itching, and/or a white discharge will be enough to diagnose a candida overgrowth. Sometimes, for further confirmation, a doctor may take a sample of a scraping of the tongue or genital discharge and look at it under a microscope to check for fungal hyphae 5 6.

These hyphae are long branches that form from the fungi and, simply described, allow the fungus to attach to the host. Think of it kind of like the roots of a tree. A tiny seed with just one root is easy to pull out of the ground, but a larger tree with a whole root system is harder to remove.

In these cases, most conventional doctors treat these infections with an antifungal pill and patients recover well.

Blood Tests

There are two types of blood tests for candidiasis. One is a blood culture (rarely used) and the other is a candida antibody test (faster and more common, but not necessarily reliable). 

Antibody test: The faster and more common blood test is an antibody test where IgG, IgM, and IgA antibodies to candida are looked for in the blood 5. This is a more common blood test now for people presenting with chronic diarrhea, whitish film on the tongue, and skin rashes to see if candida overgrowth may be contributing to these symptoms. This test is promising, but as of now it can’t diagnose a current overgrowth. Presence of antibodies shows that at some point in time a patient had some form of candidiasis, but it can’t differentiate between past and present infections 7. A doctor would use this test in conjunction with looking at your current symptoms and medical history.

Blood culture: A blood culture is done when a true systemic candida overgrowth that has gone to the bloodstream is suspected. This is very rare, and the symptoms are fever, chills, low blood pressure, and confusion 4. For this blood test, a sample of blood is cultured to see if yeast grows within it 4 8. A blood culture is very reliable for detecting systemic candidemia. However, since a systemic infection is rare and a culture takes a few days, this test is not often done 9.

Stool Tests

Stool tests have been very popular for candida overgrowth for the past five years, but we now know that they’re not as helpful as we once thought they were. Candida is a normal fungi in the gut and healthy levels of candida can be different in each person. Many people may have benign candida in their gastrointestinal tracts 1. So, a person may test as having high levels of candida, but not have any symptoms, and thus wouldn’t need to be treated for candida.

For this reason, stool tests are highly unreliable for indicating a candida overgrowth in most people.

As you can see, when looking at candida as a contributing factor to chronic illness, few of the tests we have are perfect for that. However, we’ve been told for years that candida overgrowth is one of the most common contributors to all kinds of chronic health conditions and that this can be diagnosed with a stool test.

Over time, as candida overgrowth tests get better and treatment improves, we learn more. Now we know that jumping to treating for candida overgrowth in most people with chronic illness doesn’t improve their symptoms. Let’s take a closer look at what candida overgrowth is, and is not, based on newer information.

Understanding Candida Overgrowth

For years in the functional medicine space, going through a “candida cleanse” was one of the most popular treatment options for most people with almost any sort of chronic illness. However, despite multiple rounds of cleanses, many people weren’t getting better. Let’s take a quick look at what is and is not candida overgrowth. 

What IS Candida Overgrowth?

The term “candida overgrowth” is not a medical diagnosis in itself, but rather a description of when the level of candida in a person is too high in comparison to the rest of the microbiome. 

Candida is a type of yeast (a fungus) that is normally found in the human microbiome, but too much of it can cause an infection called candidiasis 4. This is what is diagnosed commonly as a yeast infection. The most common candida (yeast) infections are genital yeast infections and/or oral thrush 4. In the clinic, we also see common symptoms of skin rashes, sugar cravings, and diarrhea.

There’s a more severe form of candidiasis where there is a systemic candida overgrowth that leads to candida in the bloodstream. This level of infection is rare and usually affects people who are immunocompromised or critically ill. In fact, it typically affects only seven per 100,000 (0.007% of) people in the United States per year 9. Symptoms of this kind of systemic candidemia are fever, chills, low blood pressure, and confusion 4.

What is NOT Candida Overgrowth?

True, systemic candida overgrowth, where there’s candida in the bloodstream, is actually pretty rare 4. Some have used the term candida overgrowth to refer to there being too much yeast in the gastrointestinal tract, which in turn may cause all types of things such as autoimmune disorders, asthma, headaches, brain fog, joint pain, bloating, itchiness, nail fungus, and more. However, there’s no evidence that candida in the gut leads to these symptoms 1 2 3.

It’s possible for normal Candida albicans spores in the GI tract to become a more virulent form of candida, if the gut microbiota is severely out of balance or the immune system is suppressed 10. This more virulent candida may then reach the bloodstream through a leaky gut wall and spread to other mucous membranes to proliferate and cause infection 4. Candida infection is especially dangerous if it then goes to the bloodstream 5 11. However, please remember, this is very rare, and still isn’t the cause of the many health issues listed above.

More common is that people have a bit of an overgrowth of candida that’s causing some chronic issues of GI upset (such as diarrhea), sugar cravings, and skin rashes. This wouldn’t be diagnosed as a full-blown systemic candida overgrowth in the bloodstream that comes with fever and chills, but it can still decrease your quality of life and should be treated, so you can start to feel better.

Treating Candida Overgrowth

If your doctor suspects that a general (not systemic) candida overgrowth is causing some of your symptoms, it’s actually very treatable. The most common treatment option for candidiasis is an antifungal such as Diflucan. In functional medicine, we often use herbal antimicrobials (or sometimes a mix of herbal and prescription antimicrobials), probiotics, and a low-carb diet.

Antimicrobials

Antimicrobials kill off fungi, such as yeast. They may be given in the form of a prescription or by using herbal antimicrobials. In our clinic, we find that patients typically feel 50% better after one course of Diflucan (fluconazole) and those who respond well to Diflucan also respond well to a month of herbal antimicrobials, such as oregano 12 13 14 15 16 17.

When using a round of herbal antimicrobials for about a month, we often have our patients also go on a low-carbohydrate diet.

Low-Carbohydrate Diet

Research has generally shown that candida diets, such as cutting out all foods with yeast in them, don’t work to fix a candida overgrowth 18 19 20 21 22 23. However, we have found that a simple, low-carbohydrate diet can be very helpful.

Yeast feeds off of sugar (carbohydrates of all kinds, even things like sweet potatoes.) Lowering your carbohydrate intake gives the yeast less to feed off of, so the yeast may stop multiplying and may also die off 24.

While we often use a low-carb diet in patients who may have candida overgrowth, we also recognize that the research on using a low-carb or low-sugar diet when treating candidiasis is debatable. A few clinical and observational studies have drawn associations between low-sugar diets resulting in lower candida counts 19 20 22 24. At the same time, other studies found that people with symptoms suggestive of candida overgrowth had no changes in symptoms after eating a candida-specific low-sugar, low-yeast diet 18 21.

The issue with the studies on diet and candida overgrowth is that most of the candida overgrowth tests look for candida levels in the stool to decrease, which we know isn’t a firm indicator of candida overgrowth. Better studies need to be done in order to understand the true effects of diet on candida symptoms.

What we look for in the clinic is an improvement of symptoms with a low-carb diet and often the addition of herbal antimicrobials. In fact, one study shows this combination is effective 22.

A diet high in carbohydrates increases the risk of chronic illness, so lowering carbohydrate intake and regulating your blood sugar is also good for general health and wellness 23.

We use the diet in conjunction with antimicrobials and probiotics because if the yeast doesn’t die off, you might start having symptoms again once you reintroduce more carbohydrates.

Probiotics

Probiotics can help improve gut dysbiosis, including yeast overgrowth. As the gut microbiome improves, leaky gut also improves as well, possibly decreasing the likelihood of a more systemic candida infection.

In terms of using probiotics specifically for candida overgrowth, probiotics seemed to reduce oral candida numbers in children and adults, which may help protect against candida infection in the mouth 25 26.

In infants, probiotics were associated with a 57% lower risk of candida colonization in preemies, and were as effective as Nystatin (a standard antifungal medication) in reducing fungal infection and improving food intolerances 27 28.

Two Simple Ways to Decrease Candida

Living with chronic symptoms such as diarrhea or rashes can be exhausting, and we want you to start to feel better.

While testing for candida overgrowth is tempting, it’s best to do any candida overgrowth testing under the guidance of a clinician who will be using testing along with the information they gather from getting to know you and your symptoms.

At the same time, there are simple things you can do at home to improve your gut health and possibly resolve chronic symptoms you may have been experiencing.

These two simple lifestyle changes create a good foundation for health and wellness, and can help with many chronic underlying health problems.

1. Eat a low-carb or low sugar diet to help decrease the growth of candida in the gut.
2. Add a good probiotic supplement to your daily regimen to improve your gut health and symptoms of yeast overgrowth.

These two steps should get you on the right path to improved health.

If you want to learn more about gut health, you can check out my book, Healthy Gut, Healthy You, which provides a more detailed plan to better gut health.

If you’ve been trying similar interventions for a while but are still struggling, we are happy to help you at the clinic, and you can fill out a patient application here. We know how frustrating it is to not feel well and we hope we can help you start to live better.

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.