Benefits of Selenium for Thyroid Health

The importance of selenium for thyroid health is often overlooked. Yet, this essential mineral plays a crucial role in thyroid hormone metabolism and may reduce the risk of autoimmune thyroid disease. 

Learn why selenium deficiency can contribute to underactive thyroid function and discover the best dietary sources of this key nutrient. 

What is the thyroid?

The thyroid gland is an endocrine organ located beneath the Adam's apple in the neck region. Its main role is to synthesize thyroid hormones, which regulate almost every aspect of the body's metabolism. 

Thyroid hormone biosynthesis is tightly controlled by an interplay between the hypothalamus and pituitary glands. 

The hypothalamus signals the pituitary to release thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to produce and secrete its main hormones, thyroxine (T4) and triiodothyronine (T3).

These hormones influence the rate at which the body converts food into energy, impacting weight management, temperature regulation, and overall energy levels. 

Additionally, thyroid hormones play a vital role in growth and development, immune system balance, cardiovascular function, and digestive processes. 

Because thyroid hormones play such a fundamental role in numerous physiological processes, impaired thyroid function can lead to a wide range of serious health issues.   

Watch the video below to learn why selenium is critical for individuals with autoimmune thyroiditis.

What is Hashimoto's disease?

Hashimoto's disease, also known as Hashimoto’s thyroiditis, is an autoimmune condition where the immune system mistakenly attacks the thyroid gland. 

This disorder is characterized by the gradual destruction of thyroid tissue, leading to inadequate thyroid hormone metabolism and underactive thyroid function, often referred to as hypothyroidism.

According to research published in StatPearls, autoimmune-related hypothyroidism is one of the most common forms of underactive thyroid function and occurs more frequently in women aged 30 to 50.

It’s estimated that around 10 percent of women experience underactive thyroid function at some point in their lives, making it one of the most common endocrine diseases in Western countries.   

Symptoms of Hashimoto’s disease are often subtle at first and may include fatigue, unexplained weight gain, sensitivity to cold, dry skin, hair loss, and constipation. 

As the disease progresses, the thyroid's ability to produce hormones diminishes, resulting in further metabolic and hormonal imbalances linked to an increased risk of cardiovascular disease, menstrual irregularities, infertility, and mental health issues. 

Benefits of selenium for thyroid health

The thyroid gland contains the body’s highest concentration of selenium. This indicates its importance for maintaining optimal thyroid function and explains why a selenium deficiency can significantly contribute to various thyroid disorders. 

Here are four key benefits of selenium for supporting thyroid health.

1. Promotes thyroid hormone balance

Selenium is an essential part of the enzyme iodothyronine deiodinase, which converts T4 into the more active form, T3.

Without adequate selenium, this conversion process can be impaired, leading to insufficient levels of T3, which is critical for regulating metabolic processes, energy levels, and overall physiological function. 

Selenium also contributes to the activity of glutathione peroxidase, an antioxidant enzyme that protects thyroid cells from oxidative stress. This can help reduce inflammation and cellular damage linked to autoimmune attacks on thyroid tissue. 

A study published in Thyroid investigated the effect of selenium supplementation on individuals with Hashimoto’s disease and reported that those taking selenium supplements showed marked improvements in disease activity and progression.  

The authors concluded, “Our study suggests that selenium supplementation is safe and holds potential as a disease-modifying factor for Hashimoto-associated hypothyroidism.”

2. Facilitates iodine balance 

In addition to selenium, iodine is another vitally important nutrient for thyroid health as it serves as an essential building block for thyroid hormones. 

Selenium-dependent enzymes are critical in maintaining iodine balance and ensuring that iodine can be effectively incorporated into thyroid hormones. Specifically, these enzymes ensure that iodine is properly integrated into T4, which contains four iodine atoms, and T3, which contains three iodine atoms. 

The relationship between selenium and iodine metabolism is also essential for the conversion of thyroid hormones, with selenium helping to convert inactive T4 into the active T3 form. 

“Without adequate selenium, iodine deficiency can become more problematic as it impairs thyroid hormone production, exacerbating metabolic imbalances and thyroid-related disorders,” explains Dr. Berg.

3. Supports balanced immune function  

Selenium is known for supporting balanced immune function, which is particularly important for individuals with autoimmune thyroid conditions such as Hashimoto's disease. 

This has been confirmed by research published in Clinical and Translational Science, reporting that selenium supplementation directly reduced concentrations of thyroid antibodies responsible for autoimmune thyroiditis. 

It’s believed that selenium modulates the activity of various immune cells, which can help maintain balanced immune system function and reduce the risk of autoimmune attacks on thyroid tissue.

4. Helps detoxify heavy metals

Selenium is essential for detoxifying heavy metals, which have been found to negatively impact thyroid health. 

Heavy metals such as mercury can accumulate in the body and disrupt thyroid hormone synthesis by interfering with the enzymatic processes involved in T4 to T3 conversion.

Selenium promotes heavy metal detoxification by facilitating the production of selenoproteins, which convert inorganic mercury into a less toxic form. This renders mercury less harmful and enables its elimination from the body, reducing its potential to disrupt thyroid function.

Signs of selenium deficiency

In addition to playing a critical role in thyroid function, selenium is essential for overall metabolic processes, immune system health, and antioxidant defense. 

Unsurprisingly, selenium deficiency can lead to a wide range of health issues, including:

• Fatigue and weakness

• Weakened immune functions 

• Thyroid issues

• Hair loss

• Mood changes

• Cognitive decline

• Reproductive problems

• Pour wound healing

• Joint pain

• Chronic inflammation

• Poor detoxification 

• Skin changes

If you are concerned about your thyroid health or show signs of a selenium deficiency, it’s crucial to consult a medical professional for a thorough evaluation of your health status. 

A doctor can conduct blood tests to assess selenium levels and thyroid function, which helps identify any deficiencies or imbalances that may be affecting your health.

Best sources of selenium 

Maintaining optimal selenium levels relies on adequate dietary selenium intake, and it’s recommended that adults consume around 55 micrograms (mcg) per day.  

Brazil nuts are among the richest sources of selenium, with just one nut delivering more than double the recommended daily intake.

In addition to Brazil nuts, plenty of other foods such as seafood, meat, dairy products, and eggs help support optimal selenium balance and promote thyroid function. 

Here are selenium-rich foods and their selenium content per 3 ounces (85 grams):

• Brazil nuts: 810 mcg

• Yellowfin tuna: 92 mcg 

• Sardines: 45 mcg 

• Halibut: 47 mcg 

• Shrimp: 42 mcg 

• Beef: 33 mcg 

• Chicken: 24 mcg 

• Turkey: 30 mcg

• Eggs: 19 mcg

• Sunflower seeds: 60 mcg

• Yogurt: 11 mcg

Key takeaways

There are several benefits of selenium for thyroid function, and maintaining optimal selenium status is critical in promoting thyroid health and reducing the risk of Hashimoto's disease. 

Not only is selenium needed to produce thyroid hormones, but it also plays a critical role in iodine balance, immune system regulation, and the detoxification of heavy metals, all of which contribute to optimal thyroid function.

FAQ

1. Can selenium help thyroid function?

Yes, selenium plays a critical role in thyroid function by supporting the production of thyroid hormones, facilitating the conversion of thyroxine (T4) into the more active triiodothyronine (T3) form, and providing antioxidant protection to thyroid cells.

Selenium deficiency has been linked to poor thyroid function and can increase the risk of thyroid-related autoimmune conditions such as Hashimoto’s and Graves’ disease.

2. How much selenium can you take daily for thyroid support?

To support thyroid health, it’s recommended to consume around 55 micrograms (mcg) of selenium daily. However, it's important to avoid exceeding 400 mcg daily, as excessive intake can lead to acute selenium toxicity linked to gastrointestinal distress and neurological issues.

3. Who should not take selenium?

Selenium shouldn’t be taken by individuals with inadequate iodine status as it can worsen thyroid dysfunction and exacerbate the effects of iodine deficiency.

In addition, selenium should only be taken under medical supervision by individuals with certain autoimmune conditions, including lupus and rheumatoid arthritis, as well as those taking blood-thinning medications and immunosuppressant drugs.

4. What are the symptoms of selenium deficiency?

Common selenium deficiency symptoms include unexplained weight gain, fatigue, weakness, hair loss, recurring infections, mood changes, and fertility issues. 

Sources

1. https://www.ncbi.nlm.nih.gov/books/NBK459262/ 

2. https://pubmed.ncbi.nlm.nih.gov/38243784/ 

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301566/