What?! Parasites can play a role in hypothyroidism

What?! Parasites can play a role in hypothyroidism

Do you know what could be eating you? Yeah parasites!

I know. I know. So gross. When my doctor first mentioned that parasites might be playing a role in my hypothyroidism. I said HELL NO.

Seriously though turns out these human-feasting organisms could be living in your body. I didn’t enjoy doing the stool testing, but I’m so happy that I did it. Turned out I didn’t have parasites, but I wasn’t off the hook. I have an overgrowth of Candida, fungus invading my gut. If I hadn’t done this stool test I would have never known. I will be writing more about Candida soon but, in the meantime, parasites have been found in the stool of hypothyroid patients and destroying them makes all the difference.

Written by Eric M. Osansky, DC, CCN, IFMCP

Most people with hypothyroidism have the condition known as Hashimoto’s Thyroiditis. And there is a triad of autoimmunity that includes

1) a genetic predisposition,

2) an environmental trigger, and

3) an increase an intestinal permeability (a leaky gut).

With regards to the environmental trigger, one potential trigger of thyroid autoimmunity is parasites.

So how can parasites lead to hypothyroidism? Well, as I mentioned in the opening paragraph, most people with hypothyroidism have the autoimmune thyroid condition known as Hashimoto’s Thyroiditis. This condition involves the immune system attacking the thyroid gland, which in turn decreases the production of thyroid hormone, and over time this commonly leads to hypothyroidism. People with hypothyroidism/Hashimoto’s have different triggers, and parasites is one of those potential triggers.

What Are The Symptoms Of A Parasitic Infection?

First of all, not everyone with a parasitic infection experiences symptoms. On the other hand, gastrointestinal symptoms are common, and can include stomach pain, gas, bloating, and/or diarrhea. Some people will experience itching around the anus. And there can be other signs and symptoms as well, such as fatigue, weight loss, nausea, body aches, and anxiety.

How Do People Get Infected With Parasites?

Transmission of parasites usually occurs through a fecal-oral route. Most people who have a parasitic infection become infected by eating food or drinking water that has been contaminated. However, some parasites that live in the blood can get transmitted through the bite of a mosquito.

What Are The Most Common Types Of Parasitic Infections?

Below are some of the more common parasitic infections:

Blastocystis hominis. Although some consider Blastocystis hominis to be a commensal parasite, the more recent research shows that this is a pathogenic parasite. In addition, the research shows that Blastocystis hominis can cause an increase in inflammation (1), and even increase the permeability of the small intestines (2). A case report involving a 49-year old man with Hashimoto’s Thyroiditis shows that eradicating Blastocystis hominis resulted in a decrease of his thyroid antibodies (3). I personally have had a few patients with Hashimoto’s test positive for Blastocystis hominis and go into remission upon eradicating it.

Entamoeba histolytica. This is a pathogenic parasite that is associated with intestinal and extraintestinal infections (4). In other words, it not only can affect the intestines, but it can also affect extraintestinal sites such as the liver, brain, and lungs (4). Infection with this pathogen can lead to the disease called Amebiasis, which is more common in people who live in poor sanitary conditions. While many people who are infected do develop symptoms, this isn’t the case with everyone. Many times the symptoms are mild and can include loose feces, stomach pain, and stomach cramping, although there is also something called amebic dysentary, which is a more severe form of amebiasis.

Giardia lamblia. This parasite causes the illness known as giardiasis, and is usually found on surfaces or in soil, food, or water that has been contaminated with feces from infected humans or animals (5). As a result, it is usually transmitted by drinking contaminated food or water. Although some people infected with this parasite have no symptoms, some of the common symptoms include diarrhea, gas, stomach cramps, and nausea/vomiting.

Cryptosporidium. This parasite can lead to the condition known as “cryptosporidiosis”, and is usually characterized by watery diarrhea (6). Drinking contaminated water is the most common method of transmission. In addition to watery diarrhea, some other common symptoms include stomach cramps or pain, nausea, vomiting, weight loss, and dehydration. The condition frequently self-resolves in one to two weeks in those who have a healthy immune system.

Hookworm. These soil-transmitted helminths live in the small intestine, and the hookworm eggs are passed in the feces of an infected person. The larvae are able to penetrate the skin of humans, and the infection is usually acquired by walking barefoot on contaminated soil. Most people with a hookworm infection are asymptomatic, although some will experience gastrointestinal symptoms. One of the more serious side effects of a hookworm infection is anemia due to blood loss (7).

Pinworms. Pinworms can live in the colon and rectum of humans, and they commonly cause itching around the anus, which is caused by the female pinworm laying her eggs. Like many other parasitic infections, pinworms are spread by the fecal-oral route, and one of the reasons why they are easily spread is because they can survive for two to three weeks on clothing, bedding, or other objects (8).

Tapeworm. Dipylidium is tapeworm of cats and dogs, and humans usually become infected by accidentally swallowing a flea infected with tapeworm larvae (9). Diphyllobothriosis is a human disease caused by tapeworms of the genus Diphyllobothrium, and it’s commonly transmitted by eating raw or poorly cooked fish (10).

How Can An Infection With A Parasite Cause Hypothyroidism?

First of all, it’s important to understand that most parasitic infections won’t result in hypothyroidism. But certain parasites can trigger an autoimmune response, and thus if someone has a genetic predisposition for Hashimoto’s Thyroiditis, then having a parasitic infection can lead to the development of this condition. And many cases of Hashimoto’s Thyroiditis will result in subclinical hypothyroidism, which over time can progress to overt hypothyroidism. So a parasite usually doesn’t directly affect the thyroid gland, but instead affects the immune system, which in turn causes it to damage the thyroid gland, thus leading to hypothyroidism.

What Testing Is Available To Detect The Presence Of Parasites?

Stool testing is typically the method used by most healthcare professionals to determine if someone has a parasitic infection. Just keep in mind that false negatives are common, and because of this I always recommend for my patients to collect a stool sample on at least three different days for greater accuracy. Plus, there are different methods of testing for parasites in the stool. One method is Polymerase Chain Reaction (PCR) testing, which looks at the DNA of the parasite. The advantage this method has over others is that a live parasite doesn’t need to be detected in the stool. However, even this technique can result in a false negative. Other methods of testing for parasites in the stool include an Ova and Parasite (O&P) exam, which is a microscopic evaluation of a stool sample. Some companies use a Trichrome staining technique.

How Do You Treat A Parasitic Infection?

Metronidazole is an antibiotic commonly used to eradicate many different parasitic infections, including giardia, Entamoeba histolytica, and Blastocystis hominis. However, natural agents can also be effective in eradicating parasites. Some of the more common agents used to eradicate parasites include the herbs wormwood, black walnut, clove, and oregano oil. Saccharomyces boulardii can also be beneficial, and a study comparing saccharomyces boulardii and Metronidazole showed that both were equally effective at killing parasites (11).

I personally recommend a natural treatment approach for my patients with most cases of parasitic infections. I commonly recommend this herbal complex that contains wormwood, black walnut, and clove, and I usually will also recommend oregano oil. And based on the study I mentioned earlier it probably would be a good idea to take saccharomyces boulardii as well. When a patient of mine has a parasitic infection I will recommend for them to take the herbal complex for 10 days, and then after taking a 10 day break I recommend for them to take it for another 10 days. This process not only helps to eradicate the adult parasites, but the babies as well. Speak with your doctor about treatment methods should you be found to have parasites.

Are All Parasites Bad?

Although I’ve focused on parasites as being a possible autoimmune trigger, you might be surprised to learn that there can be some health benefits to getting infected with certain types of parasites. In fact, “helminth therapy” might offer protective benefits against certain autoimmune conditions such as Hashimoto’s Thyroiditis. But how can a parasite suppress autoimmunity? Well, regulatory T cells (Tregs) can play a role in suppressing the autoimmune response. And while certain nutrients and herbs can help to increase the number of Tregs, some studies show that helminth parasites can also lead to an increase in Tregs (12) (13).

So based on the research that shows the potential benefits of helminth therapy, how can one determine if someone is infected with a “good” parasite or a “bad” parasite? Well, if someone tests positive for a parasitic infection and has obvious gastrointestinal symptoms then this is a pretty good sign that this is a pathogenic parasite. And some parasites are known for their pathogenicity. In other words, some parasites are known to cause harm and therefore should be eradicated, regardless of whether the person presents with symptoms or not. Examples include cryptosporidium, giardia lamblia, and entamoeba histolytica. While there might still be some controversy over Blastocystis hominis, as some consider this to be a commensal parasite, if one of my patients with Hashimoto’s tests positive for Blastocystis then I will have them follow an anti-parasitic protocol.

About Eric M. Osansky, DC, CCN, IFMCP

Dr. Eric Osansky is a chiropractic physician, clinical nutritionist, and a certified functional medicine practitioner through the Institute For Functional Medicine. He is the founder of Natural Endocrine Solutions, and he has a practice in Charlotte, NC which focuses on thyroid and autoimmune thyroid conditions.

READ NEXT: Hashimoto’s & The Infection Connection


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4249314/ (1)

https://www.ncbi.nlm.nih.gov/pubmed/11755426/ (2)

https://www.ncbi.nlm.nih.gov/pubmed/26230132 (3)

https://www.cdc.gov/parasites/amebiasis/pathogen.html (4)

http://www.cdc.gov/parasites/giardia/index.html (5)

http://www.cdc.gov/parasites/crypto/general.html (6)

http://www.cdc.gov/parasites/hookworm/index.html (7)

http://www.cdc.gov/parasites/pinworm/gen_info/faqs.html (8)

http://www.cdc.gov/parasites/dipylidium/index.html (9)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2620636/ (10)

https://www.ncbi.nlm.nih.gov/pubmed/20922415 (11)

https://www.ncbi.nlm.nih.gov/pubmed/24712468 (12)

https://www.ncbi.nlm.nih.gov/pubmed/24532574 (13)

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About Dana Trentini

Dana Trentini founded Hypothyroid Mom October 2012 in memory of the unborn baby she lost to hypothyroidism. This is for informational purposes only and should not be considered a substitute for consulting your physician regarding medical advice pertaining to your health. Hypothyroid Mom includes affiliate links including the Amazon Services LLC Associates Program.


  1. I got diagnosed with Lyme’s disease five years ago, and then all the autoimmune symptoms started besides my regular day today pain fatigue and brain fog even after getting on antibiotics… Ticks are known to carry more than one disease “parasites” but most Drs say your just depressed or it’s just because XYZ , they don’t test for parasites in NY we’re I lived so loosing job house ect gave me all the room to feel ! “Ya I’m a little depressed “ I feel like I get hit by a truck every morning and I forget what side of the rd to drive on . Ahhh tell me something I don’t know. Love this pin !
    Sincerely 👍

  2. Abbey velikovsky says

    I have parasite and I have low thyroid problems
    Very low energy , and gas , as well stomach hurts
    I just find out I have hashimoto

  3. Abbey velikovsky says

    I think I have parasites . I got hashimoto
    What kind of medicine I take for parasites
    I take Armorg for thyroid

  4. I am thinking about the parasites -hypothyroidism connection linked to the anemia (iron deficiency) caused by hookworms, H. pylori or candida par example.

  5. Hi there, so after anti-parasite treatment, what would be the next step to improve gut health?

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