Essential Nutrients For Thyroid Function

30 Apr 2017

With the prevalence of thyroid related disorders skyrocketing, very few doctors actually look into the nutritional deficiencies, vitamins, and minerals needed to have normal thyroid function. In this article, we will separate out different vitamins and minerals needed for a healthy thyroid gland.


Vitamin D and Thyroid Function

Vitamin D is another vitamin that is important in a variety of different functions in the body. I a previous article you may have read that vitamin D is important for enhancing the function of regulatory T-cells which help keep the immune system balanced and prevent immune dysfunction. One study found an inverse correlation between Vitamin D levels and thyroid antibodies (12). This means that the higher the Vitamin D was, the lower the immunoreactivity there was towards thyroid tissue. Vitamin D is also required for the entry of thyroid hormone into the nucleus of the cell for cellular metabolism. Interestingly, there has been a correlation with individuals with Hashimoto’s and a gene defect in the Vitamin D receptors on cells (13). This means that the need for Vitamin D if you have Hashimoto’s is even greater than if you don’t. If you suspect any sign of immune dysfunction or any sign of thyroid dysfunction it is important to get your Vitamin D levels checked. We check for both forms of vitamin D: 25-OH Vit D, as well as 1,25-OH Vit D. While both are important to look at the form of vitamin D that is a better marker for overall nutritional status is the 25-OH Vitamin D form. We like to see that in the 60-80 ng/mL range, with people who have an autoimmune pushing at or slightly above 80.

Food Sources of Vitamin D

The best food source of Vitamin D is seafood (like Cod, Salmon, Herring, Sardines, Tuna). Other good sources include: Liver, Eggs, Dairy, Mushrooms, and of course you can’t forget natural sunshine!

Selenium and Thyroid Function

Selenium is perhaps one of the most important cofactors in thyroid hormone synthesis. In fact, ounce for ounce the thyroid contains more selenium by weight than any other organ in the body (1). Selenium is important for thyroid function in two different ways:

  • Selenium acts as an antioxidant by helping build a certain class of enzymes called Selenoenzymes. These include both glutathione peroxidase and thioredoxin reductase. What these enzymes do (particularly when it comes to the thyroid gland) is help act as an antioxidant to harmful free radicals. Even during normal thyroid function, the thyroid generates a lot of free radicals that need to be quenched by these enzymes.
  • Remember the deiodinase enzymes? These are the very important enzymes needed in order to carry out the conversion of inactive T4 to active T3 hormone. These thyroid hormone deiodinases are selenium dependent.

In two recent studies (2,3) researchers gave a group of patients T4 without selenium supplementation, and then a group of patients T4 with selenium supplementation. In both studies they found that T4 combinened with selenium was more beneficial in decreasing the autoimmune induced inflammation towards thyroid peroxidase (the enzyme that produces thyroid hormone).

Food Sources of Selenium

The best sources of selenium come from foods like: Brazil nuts, meat, and seafood. With the mass production of certain crops, there has been a depletion of selenium in the soil. Because of this, your odds of getting crops and animal products with higher content of selenium come from locally grown produce.

Iodine and Thyroid Function

Iodine seems to be one of the more controversial nutrients in thyroid health. The World health Organization estimates that over 30% of the world’s population is iodine deficient (4). Most of these deficient people come from underdeveloped nations. There seems to be two polar opposite camps when it comes to Iodine supplementation: some say you need lots of it, and others say no don’t take it because it will fuel thyroid autoimmunity. Based on 4 different interventional studies it seems to be clear that iodine supplementation does increase autoimmunity toward your thyroid gland (5,6,7,8). Another study(9), showed that people with autoimmune thyroid benefited from a lower iodine diet. The same study found that 78.3% of people in the low iodine group regained normal thyroid function, while only 45.5% did in the control group.

So why does iodine seem to increase autoimmunity?

This is thought to be believed by upregulating the TPO enzyme, which creates a lot of free radicals. Loading selenium before taking Iodine is thought to help decrease the immunoreactivity of iodine alone.

Food Sources of Iodine

The best natural sources of Iodine include: Seaweed, such as kelp, nori, kombu, wakame, as well as ocean fish. Other fortified sources include iodized salt. It is important to note that salt found in commercially prepared food should only be considered fortified unless proven otherwise.

Iron and Thyroid Function

Iron is one of the most important metals in our body. It is important to find a doctor that regularly check your iron to make sure that it doesn’t go to high or too low because it can affect virtually how everything functions. When it comes to the thyroid, thyroid peroxidase is considered a heme protein and requires iron for its synthesis. This means that iron deficiency reduces the activity of this enzyme. One study showed that women with hypothyroidism had greater incidences of iron deficiency compared to the control group (10). And given that another study showed that when animals were iron deficient it decreased T3 by 43% and total T4 by 67% (11), it makes getting screened for an iron deficiency that much more important when you have thyroid dysfunction.

Food Sources of Iron

The best sources of iron comes from animals. There are two different types of dietary iron sources: heme-bound and nonheme-bound. Heme-bound sources of iron are usually found in anything that has been living and has blood. These are animal products like: liver, animal meats, seafood. Nonheme-bound sources usually include the meats listed above, but then other foods

Nonheme-bound sources usually include the meats listed above, but then other foods like: lentils, beans, peas, spinach, beetroot, broccoli, or cooking in a cast iron skillet! It is important to know that nonheme bound iron absorption is poor at around 2-20%, whereas homebound absorption is much higher at 15-35%.

Vitamin A and Thyroid Function

Just like Vitamin D, Vitamin A is another fat-soluble vitamin that is very important when it comes to thyroid function. Within the brain, both vitamin A and thyroid hormone receptors work together to maintain proper function of thyroid hormone at the level of the pituitary gland. It appears that with vitamin A deficiency the pituitary gland becomes insensitive to changes in TSH. Certain animal studies have shown that one of the earliest signs of Vitamin A deficiency was hypothyroidism. They correlated a decrease in vitamin A with: an increase in mass of the thyroid gland as well as less serum T4.(14)

Food Sources of Vitamin A

Since vitamin A has an orangey-red hue, the best sources usually come from vegetables/tubers with that same color. Things like Carrots, Sweet Potatoes, and even some squashes. Other good sources include dark green leafy vegetables, liver, and cod liver oil.

Copper and Thyroid Function

Copper is another important metal to have that regulates a whole bunch of different enzymes. One study done in August of 2010 (12), revealed that copper was important for a vital brain area called the hypothalamus. When deficient it leaves the hypothalamus unable to regulate thyroid hormone effectively. That same study showed that copper deficient pregnant rats gave birth to infant rats that produce 48% less T3 than those born from healthy mothers.

Food Sources of Copper

Copper comes from a variety of sources, some of which include: Liver, sesame seeds, cashews, sunflower seeds, walnuts and apricots.

Zinc and Thyroid Function

Zinc is needed for both the production and use of thyroid hormone. One study showed that people with a deficiency of zinc had a reduced liver deiodinases by 67%(13). Another study showed that in a select group of patients who had low levels of Free T3, normal T4, and elevated reverse T3, with a coexisting zinc deficiency, when they took oral zinc for 12 months this normalized Free T3, decreased reverse T3 and normalized TSH levels. (14)

Food Sources of Zinc

Food sources of zinc include seafood (especially oysters), red meats, organ meats, whole grains, nuts, and legumes.

Other Nutrients Involved in Thyroid Function

In my research, I came across a video filmed by Dr. Peter Osborne, who is a fantastic resource and brought to my attention new deficiencies that I was not currently aware of. Certain other nutrients involved are:


A steady intake of protein is required for the building blocks of both neurotransmitters, as well as the backbone of thyroid hormone. One particular amino acid from protein that is very important in thyroid function is Tyrosine.


B-vitamins are used in over 250 different biochemical processes in the body. They are heavily used in the energy producing factories in our cells called the mitochondria. So when our metabolism increases due to thyroid hormone, the need for B-vitamins also increases.


Magnesium is thought to be the 2nd most common nutritional deficiency next to vitamin D. Dr. Osborne states that magnesium is needed to help produce TSH.

Vitamin C

Vitamin C is a potent antioxidant that helps with the production of thyroid hormone as well as helping to control oxidative damage in the thyroid gland.

Is Your Doctor Checking Your Nutrient Levels?

Traditional medicine normally focuses on medicating with thyroid hormone. Although thyroid hormone may be important in some cases, most people who are placed on thyroid hormone still have thyroid symptoms. If you are still having thyroid symptoms despite talking with your doctor, you may be nutrient deficient. If you are looking for doctors who take a holistic approach, or have questions please reach out to us by clicking the button below.


Dr. Scott Beyer

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