Can Parasites Cause Thyroid Problems?
Inside: Can parasites cause thyroid problems? What are the symptoms of parasites? How to test for parasites. What’s the best treatment for parasites.
Hashimoto’s Thyroiditis is an autoimmune disease and is the most common cause of hypothyroidism in the world.
Its prevalence has increased in recent years. The exact cause of this disease is still unknown, but we know that it affects middle-aged women the most.
In Functional Medicine, we know that there are root causes to autoimmune conditions like Hashimoto’s and by improving those underlying causes we can improve this condition.
Hashimoto’s Thyroiditis is caused by the interplay between environmental root causes and your genetic factors. Now we can’t change our genes but if we change the environment which causes the trigger of this autoimmune condition we can reverse or control it in a better fashion.
In this post, we discuss a potential intestinal parasite called Blastocystis Hominis as the underlying root cause of the Hashimoto’s.
Can Parasites Causes Thyroid Problems
Blastocystis Hominis is the most common intestinal parasite infecting humans, and can often cause parasitic thyroid nodule. This parasite is more prevalent in developing countries as compared to developed countries.
But I see this parasite very often in my patients when I am doing testing for it. The prevalence of this parasite in developing countries can be around 60%, while in developed countries it varies from 1.6% to 16 % [1,2].
It has been thought that this parasite is not pathogenic in most of the healthy people and that its presence does not signify any infection.
But recently it has been shown that this parasite can cause immune dysfunction and can lead to activation of certain immune cells which can lead to inflammation which ultimately can trigger autoimmune conditions like Hashimoto’s.
So yes parasites like Blastocystis can cause thyroid problems. Parasitic thyroid nodule can be a problem for several people and should be tested. There are other intestinal parasites Entamoeba histolytica, Giardia lamblia, worms that can also trigger thyroid dysfunction but currently we don’t have solid research to support this connection.
How do Parasites Cause Thyroid Problem
Most people will think how an intestinal parasite causes dysfunction of the thyroid gland which is not even closely located to the GI tract.
The answer to that question is that Hashimoto’s disease is a condition where your body produces antibodies that cause the destruction of the thyroid gland. These antibodies are produced most of the time in reaction to something external like a particular food, stress, toxins, or infections like parasites.
There was a case report  that was published which showed that a patient with Blastocystis Hominis was also found to be positive antibodies for Hashimoto’s Disease. After he was treated for Blastocystis the patient’s antibodies and thyroid levels improved.
Later on, a prospective cohort study  was done which looked for a connection between Blastocystis infection and Hashimoto’s disease.
In this study patients were divided into three groups, The first one was patients with Hashimoto’s disease and didn’t have Blastocystis, the second group had Hashimoto’s and also had Blastocystis infection and the third group was healthy people.
What they noticed was that at baseline the thyroid antibodies were highest in people with Blastocystis infection also their thyroid levels were the lowest in the patients with Blastocystis infection group too.
The group with Blastocystis infection was given treatment and they saw significant improvement in thyroid test results like TSH and TPO antibody levels in these patients.
The reason for this improvement was because of IL17 response. Blastocystis causes immune dysfunction by increasing the levels of IL17 which is a kind of chemical mediator in your body that causes inflammation.
Previous studies have shown that the higher the number of IL17 in people, the lower the thyroid hormone levels are.
As Hashimoto’s is an inflammatory condition, anything that reduces the levels of IL17 should help with this condition.
And this is what they observed in this study. After treatment of Blastocystis the level of IL17 decreased and also they saw improvement in thyroid levels.
What are The Symptoms of Having a Parasite
The most common symptoms associated with parasites are as follows —
- Loss of appetite
- Skin rash or hives
- Histamine reactions
- Abdominal pain, bloating
- Diarrhea or constipation
- Upset stomach
- Weight loss
- Weakness or fatigue
- Anxiety or mood changes
How to Test for Parasites
Blastocystis Hominis and other parasites are intestinal parasites so they need to be tested through stool cultures and microscopic examination to check for its presence.
But with any parasitic examination, the test is user-dependent and sometimes can be negative even if the parasite causing thyroid dysfunction is present as it is hard to find or might be present in small numbers.
Some of the specialized labs are using the PCR technique along with the culture to increase the chances of finding this parasite.
So instead of getting a regular stool test done through a regular lab, you need to get a stool test done through a lab that specializes in parasite testing.
How to Treat Blastocystis Hominis
Now let’s say your test result did show that you have this parasite how can you get rid of it.
Below are the 4 treatments available for Parasites That Cause Thyroid Problems —
1. Metronidazole: This is a conventional antibiotic that has been used for a long time to help with Blastocystis infection. Most of the patients will respond to this drug. But there are some who will have persistent infection despite this medicine. 
2. Alinia: This is an antiparasitic medication that has been used for the treatment of various parasites. As there are more people resistant to metronidazole this is an alternative treatment for the blastocystis and works really well. 
3. Saccharomyces boulardii: S boulardii is a non-pathogenic yeast and is used in GI conditions very often. It modulates the intestinal immune response and also interferes with the pathogen colonization of the intestinal mucosa. It is quite safe. In one of the studies showed a high cure rate of 94% when given for Blastocystis patients. 
4. Oil of oregano: Oil of oregano has been used for a long time for various medical conditions and it has shown to have antimicrobial, antiviral, and antifungal properties.
There was also a study done to see if oil of oregano can eradicate Blastocystis hominis and other parasites. And this study did show positive results after treatment with oil of oregano symptom wise as well as the ability to eradicate parasites. 
Whats is My Approach when Parasites cause thyroid issues.
I feel Blastocystis is a parasite which in some people can certainly cause immune dysfunction and also can be the underlying reason for thyroid issues or gut related symptoms.
I also feel that just the treatment of blastocystis is not enough and it can relapse back, so it is important to improve the gut immunity and also work on eradication.
I start people on Oil of oregano and S. Boulardii treatment for 4- 6 weeks and see if they improve.
Along with this I always recommend an anti inflammatory diet for my patients.
And focus on foods that help heal the gut and also at the same time can help kill the parasites, and they are garlic, coconut oil, turmeric, ginger.
If this does not resolve the issues then going on Metronidazole is the next step.
Most of the people will get better with doing this 2 step process for eradicating the Blastocystis.
Summary of Parasite causing Thyroid Dysfunction —
So Blastocystis is a parasite which can be the underlying cause of Hashimoto’s disease. It is not pathogenic in every healthy patient, but people who have Hashimoto’s should have this evaluated. We saw that studies show that eradication of this parasite lead to an improvement in Hashimoto’s disease for the patient. There are various ways to help eradicate this parasite which includes natural ways, diet, and also pharmaceutical measures.
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