Candida and Autoimmune Thyroid Disease: Is There a Link?

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Candida (yeast) is a part of your normal flora, residing harmoniously with other organisms in your gut, reproductive tract, mouth, and skin. In people with healthy immune systems, the presence of Candida is harmless.

However, when a change in the balance of your flora occurs (for example, from taking an antibiotic), or your immune system becomes weakened (for example, from experiencing chronic stress), Candida may overgrow and cause an infection, called Candidiasis.

Candida infections vary widely in their severity, from mild infections of your mouth (thrush), fingernail, intestines, or vagina to rare but potentially life-threatening infections like meningitis or pyelonephritis.

Due to the important role your immune system plays in controlling Candida growth, it's sensible to wonder whether a link exists with autoimmune thyroid disease.

Exploring the Candida and Thyroid Link

The scientific data supporting a link between Candida and autoimmune thyroid disease is overall scant. That said, if a link does exist, here are some potential theories:

Molecular Mimicry

Molecular mimicry implies there is a structural similarity between a foreign antigen (an antigen is a substance that activates your immune system) and a host's self-antigen.

If molecular mimicry exists between Candida and the thyroid gland, a person's immune system may misguidedly launch an attack against their own thyroid—meaning the immune system mistakes the thyroid gland for a large yeast infection.

Superantigens

Another theory that has been used to explain some infectious/autoimmune disease connections involves the concept of "superantigens."

A superantigen is a protein that triggers the mass activation of immune system cells. If overgrown Candida releases superantigens, the immune system may begin attacking the thyroid gland or other tissues within the body.

Distracted Immune System

Some experts believe that a "distracted immune system" may be the culprit linking Candidiasis with autoimmune thyroid disease, meaning that a person's immune system is so focused on attacking the thyroid gland that it neglects to keep Candida levels balanced, leading to uncontrollable growth.

Under this theory, a person's autoimmune thyroid disease makes them more vulnerable to Candida infections. This is in contrast to the first two theories which suggest that Candida triggers or worsens a person's autoimmune thyroid disease.

No Link

Of course, some experts believe that there is likely no link between Candida overgrowth and autoimmune thyroid disease.

Both Candida infections and autoimmune thyroid disease are fairly common diagnoses—so, it could just be coincidental that a person suffers from both.

Moreover, there are so many factors (besides an immune system problem)—uncontrolled diabetes, obesity, poor hygiene, etc.—that contribute to Candida overgrowth. Figuring out which factor is the main culprit behind a yeast infection can be tricky. In addition, there may be more than one factor involved.

Why You Keep Getting Yeast Infections

What This Potential Link Means for You

If you do suffer from frequent Candida infections, there are no guidelines suggesting you undergo a thyroid evaluation.

That said, it could be that symptoms you are attributing to a Candida infection (for example, fatigue, skin rashes, or digestive issues like bloating or constipation) may actually be thyroid-related. This is why a visit to your doctor for a proper diagnosis is essential.

Treating Candida Infections

There is no evidence suggesting treating Candida overgrowth will ease your thyroid symptoms. Regardless, be sure to see your doctor if you have a yeast infection.

Candida infections are treated with a medication called an antifungal, that can be given topically, orally, or intravenously.

Preventing Candida Infections

Whether or not there is a link between your yeast infections and your thyroid, it's a good idea to try and prevent yeast infections from occurring in the first place.

Some basic strategies you can adopt include:

  • Wearing loose-fitting, cotton clothes, especially underwear
  • Avoiding certain medications like antibiotics or corticosteroids (if possible)
  • Practicing good hygiene

In addition, some experts recommend the "Candida diet " based on the premise that sugar may promote the growth of yeast. With this diet, individuals eliminate sugar, white flour, alcohol, and some dairy products.

While there is no robust scientific data to support this diet yet, it may be worth a try under the guidance of your doctor.

A Word From Verywell

Even though scientists have not yet found a concrete link between Candida and autoimmune thyroid disease, try to remain focused on caring for yourself. This means taking your thyroid and/or antifungal medication as directed, seeing your doctor for regular check-ups, and managing your stress healthily.

Sources:

Benvenga S, Guarneri F. Molecular mimicry of autoimmune thyroid disease. Rev Endocr Metab Disord. 2016 Dec;17(4):485-98. dx.doi.org/10.1007/s11154-016-9363-2.

Lim JH et al. Bimodal Influence of Vitamin D in Host Response to Systemic Candida Infection-Vitamin D Dose Matters. J Infect Dis. 2015 Aug;212(4):635-44. dx.doi.org/10.1093/infdis/jiv033

Nobile CJ, Johnson AD. Candida albicans Biofilms and Human Disease. Annu Rev Microbiol. 2015;69:71-92. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930275/

Vojdani A. A Potential Link between Environmental Triggers and Autoimmunity. Autoimmune Dis. 2014;2014:437231. https://www.ncbi.nlm.nih.gov/pubmed/24688790

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