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What Causes Candida Overgrowth—and What Can You Do About It?

Written by Dr. Michael Ruscio, DC on November 22, 2024

Written by Dr. Michael Ruscio, DC on November 22, 2024 — Reviewed by Hilary Watts

• What is Candida?|
• What Causes Candida Overgrowth in the Gut?|
• Healing Candida Overgrowth in the Gut: A 4-Step Process|
• Tackle Candida Overgrowth Naturally|

In the clinic, we frequently run into patients who’ve struggled with symptoms like gas, bloating, diarrhea, skin rashes, joint pain, and brain fog. Many of them, at some point along the line, have been diagnosed with Candida overgrowth based on stool or urine testing. They’ve been told to follow a strict diet and take various herbal supplements to kill the Candida.

While I do use diet and supplements when treating Candida overgrowth, my big-picture goal is different. Rather than trying to eradicate Candida, I want to restore balance in the gastrointestinal (GI) tract so this yeast can peacefully coexist with our other gut inhabitants. 

Zooming out, we see that Candida isn’t always a bad guy. This fungi is actually a normal member of the GI tract, and it’s likely beneficial for us, as long as our other gut microbes keep it in check. But when our lifestyles and diets get out of balance, we tend to run into trouble, and this is when we can start to experience the signs and symptoms of too much Candida. 

So, let’s dive into what Candida is, the most common factors that take the gut off course, and more importantly, what we can do to right the ship. 

What is Candida?

Let me start off by clarifying that Candida overgrowth is not the same as invasive candidiasis. Invasive candidiasis is a severe infection people often get in the hospital and that can lead to life-threatening complications if not treated fully and quickly. 1.

When I talk about “Candida overgrowth,” I’m referring to elevated levels of this type of yeast in the gastrointestinal tract, specifically the small and large intestines. But Candida can also overgrow in areas like the esophagus, genitals (yeast infection), and mouth (oral thrush).

Now that I’ve got that housekeeping item out of the way, let’s dig into what Candida fungus is. 

As you’ve likely heard me say, the GI tract is home to a vast array of microbes. Bacteria make up the bulk of these inhabitants, but we also have around 200 types of fungus living in our digestive systems 2. Many types of Candida live there, but Candida albicans seems to be the most common yeast species in a healthy gut 3. 

You read that right: Candida yeast is supposed to be in the GI tract, and it’s also found on the skin 4 and in the vagina 5. I know this may come as a surprise based on the fear that’s common around Candida, but research suggests it’s a normal member of our gut flora and not necessarily something we need to fear.  

So, why is social media abuzz with Candida-killing protocols? The devil is in the details. While Candida is supposed to be in the GI tract, it also needs to be kept in check—this is one responsibility of our commensal (non-harmful) gut bacteria 6. 

You’re probably starting to see the writing on the wall—if the gut bacteria are out of balance (as in dysbiosis), Candida can take advantage of the situation and start to grow out of control. But it’s all about context: Rarely is Candida the root cause of gut imbalances 7. It’s best to think of it more as a symptom of microbial dysbiosis in general. 

Now let’s talk about how to know if you have Candida overgrowth. 

How Do You Know If You Have Candida Overgrowth?

Diagnosing a Candida fungal infection can be somewhat tricky because there aren’t any validated testing options for detecting too much Candida in the GI tract 8. Direct sampling, which is an invasive procedure, is probably the most accurate option, but it isn’t practical. 

Many healthcare providers end up using stool and urine testing or various food sensitivity tests. But I want to make it very clear that none of these provides any useful information about your gut’s Candida levels 8. 

Research does tell us that symptoms tend to correlate with microbial overgrowths, so here are the most common symptoms to look for 1 6:

• Bloating
• Gas
• Constipation
• Diarrhea
• Skin lesions (and diaper rash, even in adults)
• Itching/burning
• Vaginal yeast infection with vaginal discharge (vaginal yeast infection)
• Leaky gut
• Joint pain
• Irritability
• Depression
• Brain fog

I should clarify that gut imbalances tend to happen together, so it’s likely not just Candida that’s responsible for your symptoms. Rather, it’s a skewed ecosystem that we need to target. To understand how I restore gut homeostasis in the clinic, let’s take a look at what typically causes Candida overgrowth. 

What Causes Candida Overgrowth in the Gut?

Candida most likely plays a role in the overall health and well-being of the GI tract, but this symbiotic (mutually beneficial) relationship is based on balance. If things start to become one-sided, a whole host of negative consequences can arise.

But why does the gut ecosystem get out of balance in the first place? For most of us, we can distill it down to seven main contributing factors:

1. Acid-lowering medications—Normally, we need enough stomach acid to kill excess bacteria and fungi and prevent them from seeding (populating) the rest of the GI tract. Acid-lowering medications raise the pH of the stomach contents, which can encourage bacterial and fungal overgrowths downstream 9. 
2. Chronic stress—Chronic stress suppresses the immune system, which is like the police force of the GI tract. Part of the immune system’s job is to maintain microbial balance, but chronic stress taxes its resources, making it worse at preventing overgrowths 10 11 12.
3. Antibiotics—Antibiotics kill bacteria, but many gut bacteria are important for keeping fungus levels in check. When we lose beneficial bacteria during antibiotic treatment, Candida levels can start to rise 13.
4. Sedentary lifestyle—People who exercise regularly tend to have more gut bacterial diversity and a healthier gut microbiome than people who aren’t active. Gut diversity and beneficial bacteria make it easier to keep Candida levels where they should be 14.
5. Alcohol—Alcohol intake, especially high amounts, may increase inflammation in the gut, contributing to dysbiosis that may allow Candida to multiply unchecked 15 16. 
6. Diets high in fat, sugar, and processed foods—Consuming a Western-type diet that’s low in nutrients and high in fat, sugar, and ultra-processed foods may increase the risk of leaky gut, which may encourage microbial overgrowths and dysbiosis 10 17.
7. Smoking—Tobacco smoke may push the gut microbiome into a state of dysbiosis, which may allow for fungal overgrowth 18.

I want to reiterate that all of the above risk factors—not just Candida overgrowth—can contribute to dysbiosis in the gut. If you’ve been diagnosed with Candida overgrowth, it’s easy to fall into a cycle of fear and desperation where you’ll do anything to kill the Candida. You may try over-the-counter ointments, suppositories, creams, or prescription treatments. But just targeting Candida won’t likely lead to complete healing. 

The takeaway here is that instead of making Candida the fall guy, we need to address total gut health to restore balance in the gut microbial ecosystem. 

The great news is that we have many natural options for getting gut health back on track. If you’ve been struggling with the symptoms of Candida overgrowth, my book, Healthy Gut, Healthy You, walks you through a step-by-step gut-healing protocol to restore vibrant gut health. But you can start your journey to feeling better today by following some simple therapeutic strategies, so let’s discuss.

Healing Candida Overgrowth in the Gut: A 4-Step Process

Rather than zooming in on Candida itself, we need to intervene upstream in order to change the environment further down the GI tract. Since an unhealthy diet, sedentary lifestyle, and unmanaged stress have a huge impact on gut health, this is where I like to start. 

Step 1: Diet and Lifestyle

In my experience in the clinic, diet is unquestionably the most impactful intervention for improving gut health (and overall health). When it comes to Candida overgrowth, there seems to be quite a bit of confusion about what type of diet is best. Most of the clients I see with Candida symptoms have either read online about or been encouraged to follow an extremely low-carbohydrate meal plan, but this isn’t necessary in most cases. 

While I’m not firmly planted in any one dietary camp, I often recommend the Paleo diet, at least at first. The Paleo meal plan reduces or eliminates many problematic foods (like processed ingredients, added sugars, unhealthy fats, and common problem foods like dairy, gluten, and soy) that may promote inflammation, gut dysbiosis, and Candida overgrowth 19 20 21 22 23 24.

By removing these foods, the gut ecosystem can begin to come back into balance. Gradually, the diet  can expand to include a wider range of healthy foods.

Again, Paleo isn’t the only option. Any diet that eliminates processed foods and added sugar will likely get the gut on the path to better biome balance.  

While my clients work on their diet, I coach them on ways to incorporate daily movement. Exercise can increase gut microbial diversity, and more healthy gut bacteria means better control of Candida 25. Clients who are new to exercise can start off by walking as much and as often as possible. Once we get that foundation in place, they can begin to experiment with other types of cardiovascular training and resistance training. 

Exercise can also help us reduce stress 26 27 28, which, when unmanaged, can weaken the immune system and negatively affect gut health 11 12.

Because stress is such a normal part of daily life, I recommend my clients implement a daily stress management technique in addition to exercise. A short daily meditation, yoga practice, or spending time in nature can help to restore a balanced stress response and improve gut-related symptoms 23 29 30 31 32. 

Once we’ve got their diet and lifestyle dialed in, if a client still has Candida overgrowth symptoms, it’s time to trial probiotics.

Step 2: Probiotics

Probiotics have pleiotropic effects, meaning they act in a variety of ways to restore balance in the gut. They’re antibacterial, antifungal, anti-inflammatory, anti-leaky gut, and they promote a healthy gut immune response 1 2 33. These qualities make probiotics the perfect option for relieving Candida overgrowth symptoms.

It’s not just me saying this—scientific research supports the use of probiotics for fungal overgrowth, and they may be as effective as common antifungal medications (like fluconazole, miconazole, and nystatin) 34 35.

You may be wondering if Candida requires a specific strain of probiotic, and the answer is no. After reviewing the scientific data, it’s clear that it’s best to use a multi-strain approach 36 37 38.

In the clinic, we use a triple-therapy protocol, meaning we recommend 3 main categories of probiotics in combination. Essentially, that means taking a blend of Lactobacillus and Bifidobacterium strains, plus Saccharomyces boulardii (a beneficial yeast), plus soil-based probiotics (typically Bacillus species) for 2–3 months.

If I have clients who don’t find that diet, lifestyle, and probiotics are enough to get them across the finish line, I suggest they consider an elemental diet.

Step 3: Elemental Diet

If Candida overgrowth symptoms persist after steps 1 and 2, inflammation in the GI tract is probably why. An elemental diet can help to quell that inflammation and allow the intestines to heal.

An elemental diet is a hypoallergenic, anti-bacterial, anti-inflammatory meal replacement that can help improve the myriad GI and other conditions 39 40 41 42. The elemental diet works essentially by giving the small intestine a rest from digestion, which helps it repair and restore a healthy immune system response. 

While we don’t have research on using an elemental diet for fungal overgrowth,  evidence shows it can benefit other GI health conditions, like inflammatory bowel disease 40 43 and small intestinal bacterial overgrowth 39. Knowing that, it’s safe to assume that an elemental diet could be helpful for rebalancing Candida. 

One note of caution for people with oral Candida infections, (or thrush, when Candida grows out of control in your mouth, causing soreness, white patches on the tongue, red swelling in the corners of the mouth, and inflamed mucous membranes): The sugar in an elemental formula may be problematic for thrush, so I wouldn’t recommend using an elemental diet in this case. 

The final step to consider when treating Candida overgrowth involves antimicrobials.

Step 4: Antimicrobials

Antimicrobials include a variety of plant extracts or medications (like antibiotics and antifungals) that can knock out bad bacteria and other infectious microbes 44.

You may be thinking, why not just start with antimicrobials to get rid of Candida? In our experience in the clinic, starting out with antimicrobials may set you up for failure in the long run. 

If we bypass the foundations of improving the diet and lifestyle, and immediately target Candida with antimicrobials , the likelihood of long-term success is poor. Why? Because we’ve skipped over the root cause of the overgrowth, which is poor gut health. 

Adding antimicrobials before giving the gut a healthy foundation may kill Candida, but it also means the good microbes that can keep things stable are vulnerable. If they die along with the Candida, we’re worse off than when we started.

So, when it’s time for them, I tend to recommend herbal antimicrobials more than pharmaceutical ones. The herbal types are less likely to produce unpleasant side effects 45 or antimicrobial resistance 46 47 48, or negatively disrupt the gut microbiome 49.

Herbal options can treat gut infections and overgrowths, including Candida 48, SIBO (small intestinal bacterial overgrowth) 50 51, and H. pylori 52, plus the digestive distress that comes with them. 

If you’re interested in more detail, check out this video outlining my 4-step guide to get rid of Candida:

Tackle Candida Overgrowth Naturally

Candida is a natural resident of the gut microbiome. It normally lives in harmony with our other gut microbes, but an out-of-balance diet and lifestyle can cause it to overgrow. 

A Candida overgrowth is usually a sign of an unhealthy gut ecosystem.

Rather than immediately targeting Candida with antimicrobials, I find clients benefit the most from building a healthy gut foundation first.

If you go through this process and still feel unwell, we’d love to help you on your journey.  Check out my book Healthy Gut, Healthy You for my complete Great-in-8 gut healing protocol, or contact us at the Ruscio Institute for Functional Health to schedule an appointment.

The Ruscio Institute has developed a range of high-quality formulations to help our clients 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. The information on DrRuscio.com is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.