A key nutrient for autoimmune thyroid disease
Updated: Jan 23
· Autoimmune thyroid disease affects up to 40% of females and 20% of males
· Selenium is a key nutrient to improve thyroid autoimmunity
· Selenium has been shown to reduce oxidation (harmful molecules) by increasing important anti-inflammatory enzymes in the thyroid
You are not alone
Perhaps you have been diagnosed with a thyroid disease. You are not alone.
Up to 40% of females and 20% of males have autoimmunity against their thyroid gland. The bad news is that you’re probably dealing with symptoms like fatigue, dry skin, constipation, weight gain, and brittle nails. The good news is that there are some actions you can take to reduce the autoimmune process.
What we are going to cover in this article is a key nutrient that has been shown to improve thyroid-specific autoimmunity. I will close with some simple recommendations according to the latest research.
What is thyroid autoimmunity?
As you may already know, autoimmunity encompasses many different types of diseases. Some common names you may recognize include multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease (or IBD). Autoimmunity is a process by which your body produces immune cells and antibodies that attacks and destroys your own tissue. It’s a case of mistaken identity gone wrong.
One of the most common autoimmune disease includes autoimmune thyroid diseases such as Hashimoto’s and Graves’ thyroiditis. As you can probably tell, these are diseases where your body produces immune cells (T and B cells) as well as antibodies against different parts of your thyroid gland. In the case of Hashimoto’s, your immune system attacks the enzyme that produces thyroid hormone, which eventually leads to low thyroid levels. On the other hand, Graves’ is characterized by antibodies produced against the thyroid receptor. This leads to a state of high thyroid.
Selenium is a promising nutrient for thyroid autoimmunity
Selenium is a nutrient found naturally in our food sources (we will talk about this later). The thyroid gland contains the highest concentration of selenium in the human body. And for good reasons too.
Selenium has been shown to increase enzymes that break down harmful molecules that can damage the thyroid gland. Specifically, selenium increases the production of a class of enzymes called glutathione peroxidase. This enzyme acts like a “Pac Man” in the thyroid gland as it breaks down harmful molecules (hydrogen peroxide) into less harmful molecules (water). Not only do these harmful molecules damage thyroid tissue but also render it more susceptible for the immune system to see it as “foreign” and thus, mount an autoimmune response to your own thyroid. Therefore, it’s important to keep these harmful reactive molecules in check.
To recap, selenium has been viewed as a “pro-thyroid” nutrient given its ability to quench these reactive harmful molecules.
Show me the research
If you are like me, you want to know what additional research is out there that can help us answer this question, “Is selenium a useful tool in those with thyroid autoimmune disease?” It’s not enough to simply stop at theories and cell culture studies so let’s take a look.
An observational study (looking at this group of people over time) of 600,000 people in China showed that regions with lower selenium in their blood had higher rates of autoimmune thyroid disease. However, we cannot say whether this is a “chicken or egg” kind of phenomenon; Did the low selenium lead to autoimmune thyroid disease or did the autoimmunity lead to low selenium?
Several trials with selenium supplementation have been performed in both Hashimoto’s and Graves’. In a large study, patients given 100 micrograms of selenium had improved quality of life, slower disease progression, and lower rates of complications (an eye condition called Graves’ orbitopathy).
Furthermore, selenium supplementation has been shown to reduce antibodies produced against your thyroid.
Selenium has also been shown to be safe in pregnancy. In one study, 150 pregnant patients with autoimmune thyroid disease were given 200 micrograms of selenium per day. Their antibodies fell significantly during pregnancy and remained lowered even after they gave birth. The authors noted that “during the study period, no adverse effects due to excess selenium intake were observed in the treated group.”
It’s important to know that selenium supplementation may be helpful even if you are on thyroid replacement therapy. One paper noted that a reduction of antibodies and inflammation when selenium is given in conjunction with thyroid hormone.
Testing for selenium status
Currently, the best way to test for your selenium status is by getting blood selenium levels. This can be obtained by a simple LabCorp test ordered by your clinician. However, I may forego this test and first use dietary interventions and then track symptoms and antibody levels.
How to get selenium
Those with autoimmune thyroid disease should do their best to ensure adequate selenium intake and levels. By looking at the research, it looks like 100 micrograms per day of selenium is optimal. But how do you get enough selenium?
Brazil nuts have historically been recommended as a main source of selenium. However, the selenium content in brazil nuts varies widely. In addition, there is concern that brazil nuts may have high levels of a compound called barium that can be toxic.
Therefore, I recommend organ meats (e.g. liver) and seafoods as the best sources of selenium. If you are opposed to these sources, then I recommend muscle meats.
Grains have a high amount of selenium, but the content varies a lot depending on where the grain is sourced from. I also am concerned that getting selenium from grains is problematic given its gluten content. This is because many with autoimmune conditions also have Celiac disease that is made worse with gluten consumption.
If you are unable to get enough selenium from your diet, then supplementing may be necessary. Many of the research has supplemented patients using a form called “selenomethionine”. A dose of 100 micrograms is probably sufficient to maintain optimal levels. Many multivitamins contain some selenium (usually 50 micrograms) so check the back of your multivitamin label to make sure you are not getting too much.
How much is too much
With all of this positive information regarding selenium, it may be tempting to load up on more and more selenium. However, it’s important to know that you can get too much.
Think of this nutrient as “Goldilocks”- we want an optimal amount but not too much. It looks like doses above 200 micrograms per day may be too much. Side effects include diarrhea, liver issues, and nail changes. However, toxicity typically doesn’t occur until you reach extremely high doses of 5,000 micrograms/day (more than 25x what is typically used in studies). It is something to watch out for though.
The Bottom Line
In this article, we discussed how selenium is a key nutrient to help with thyroid autoimmune disease such as Graves’ and Hashimoto’s. Numerous studies have shown that not only are low levels of selenium linked to thyroid disease, but supplementation with selenium can improve disease progression and symptoms. I ended with giving some practical recommendations of how to measure selenium levels and how much to get in your diet/supplementation.
I hope you found this information useful and helpful in your journey back to a healthier and happier life.
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· Saranac L, Zivanovic S, Bjelakovic B, Stamenkovic H, Novak M, Kamenov B. Why is the thyroid so prone to autoimmune disease?. Horm Res Paediatr. 2011;75(3):157-165. doi:10.1159/000324442
· “Testing Nutritonal Status” by Chris Masterjohn, PhD