• Dr. Tamara Kung, ND

Get to Know Your Thyroid Hormones - Optimize Your Hypothyroid Treatment

We're getting a little geeky in this article!

Here, you'll learn what goes into producing healthy levels of your thyroid hormone. We're seeing more cases of hypothyroidism (suboptimal levels of thyroid hormones) leading to symptoms of fatigue, weight gain, brittle nails and hair loss.

So why do we want you to understand how thyroid hormones are made? Isn’t that information only necessary for doctors?

Not at all! It's important for you to get in on this too, and here's why.

Understanding what it takes to have healthy levels of thyroid hormones has two great benefits:

  1. Better understanding of the rational for treatments means you're more likely to adhere to treatment for your thyroid condition = better results! It's hard for us to remember to do things when we don't see a connection for why we are doing them.

  2. You become more involved, and can be an active collaborator in your healthcare. Working as a team is much more interesting when we feel included, and dare we suggest even elicits enthusiasm in optimizing your health!

So here it goes, let's talk thyroid! Don’t worry, it’s a digestible rundown with pictures included.

The thyroid is an endocrine (hormone secreting) gland situated at the base of your neck. Its function is to produce thyroid hormones which help every cell in your body with energy metabolism.

The first building block for thyroid hormones are thyroglobulin. These are made in the cells of the thyroid. Thyroglobulin has an amino acid tyrosine attached to it (tyrosine rich foods include pumpkin seeds, avocados, almonds, bananas, fish and eggs).

Iodine from our diet (sea vegetables, fennel, artichoke, less than 1/2 tsp of table salt), is taken in by thyroid cells. Once inside, iodine gets attached to the tyrosine. Thyroglobulin peroxidase (TPO) is the enzyme responsible for attaching the two together.

The resulting combination creates our thyroid hormones monoiodotyrosine (MIT) and diiodotyrosine (DIT). These get released from the thyroid and are used throughout the body

  • 1 MIT + 1 DIT = triiodothyroxine (T3)

  • 2 DITs = thyroxine (T4)

Fig 1. Thyroid hormone production. Image from reference 2.

T3 and T4 carry instructions to different parts of your body to influence metabolism. T3 is the more active form of the hormone, but our body produces more T4.

This is because our body doesn't need to be constantly activated, so T4 serves as a reservoir for thyroid hormone activity.

When thyroid action is needed T4 enters the cells and is converted into T3 by deiodinase enzymes.

Selenium, zinc, and copper are minerals needed by deiodinase enzymes to function, just two brazil nuts are rich in all these (you can see exactly how much they contain here)! This is why eating whole foods rich in vitamins AND minerals are so beneficial.

Supplementation to get higher doses of these minerals may also be helpful for some, and you should have this conversation with your healthcare provider if you are wondering if this will be helpful for you.

Now, with this information, you can apply it to your daily life to help you answer some questions.

Are cruciferous vegetables harmful to the thyroid?

The reason people with hypothyroidism are recommended to limit their intake of these hearty vegetables is because they contain goitrogens.

Goitrogens act by binding itself to iodine, making it unavailable for tyrosine binding.

Therefore, if someone is iodine deficient or has trouble absorbing and using it, consuming cruciferous veggies certainly does not help.

Does cooking cruciferous vegetables reduce the goitrogenic effect?

There is conflicting evidence on whether cooking, and soaking these veggies inactivates goitrogens, so it is recommended to moderate your intake if you choose to eat some (just don't have platefuls. Enjoy the variety of other veggies and fruits that are non-goitrogenic such as squash, green beans, asparagus, eggplant, carrots, celery, citrus fruits, pomegranate, blueberries, kiwis, and apples)

Will eating cruciferous vegetables cause hypothyroid?

Cruciferous vegetables will not induce hypothyroidism in someone who doesn’t have a thyroid issue. These veggies are mighty players in a healthy diet, and you can find a list of them in our previous article on the 5 health benefits of cruciferous veggies!

Should soy consumption be limited?

Soy contains a compound called isoflavones. These also interfere with thyroid hormone production because they disrupt the TPO enzyme's function (the one that attaches iodine to tyrosine).

Again, if you don’t have impaired thyroid function, avoiding soy is not necessary.

Can too much iodine be harmful to the thyroid?

Studies have found after acute intakes of excess iodine thyroid hormones slightly decreased. This can be explained by high levels of iodine inhibiting the TPO enzyme. Another explanation is that high levels of iodine reduce the amount of iodine transporters that bring iodine into cells. The effects seem to wear off once normal iodine levels return.

This is seen only in those with impaired thyroid function.

We hope this helps you understand your thyroid hormones more thoroughly. There is a lot of products and information out there, so understanding what is necessary for hormone production can help you be a better navigator.

Remember that the thyroid does not exist in isolation. It's in constant two-way communication with the rest of your body. Your thyroid not only influences your body, but what happens in and around your body also impacts the thyroid (ie. stress, immune system, diet, and environmental exposures).

Empowering you to be engaged in your health is crucial to healing. When you are proactively working with your healthcare provider, you can collaborate together more effectively. This can help reduce barriers, and enhance understanding of your expectations paving way for best results!

Disclaimer: this article is not a replacement for medical assessment and advice from your healthcare provider. Please see your local naturopath and or regular healthcare provider for individualized assessment and treatment and help you answer any questions you may have.


Bianoco, A.C., Kim, B.W. (2006). Deiodinases: implications of the local control of thyroid hormone action. The Journal of Clinical Investigation 116(10), 2571-2579. Retrieved from

Formation, storage, and release of thyroid hormones. Boundless Anatomy and Physiology Textbook. Retrieved from

Dieffenbach, S. Hypothyroidism. American Nutrition Association, 38(2). Retrieved from

Iodine. National Institute of Health: Office of Dietary Supplements. Retrieved from

Leung, .M., Baverman, L.E. Consequences of excess iodine. Nature Reviews Endocrinology, 10(3), 136-142. Retrieved from

Paul, T., Meyers, B., Witorsch, R.J., Pino, S., Chipkin, S., Ingbar, S.H., Braverman, L.E. Metabolism, 37(2), 121-124.

Sargis, R.M. How your thyroid works. Endocrine Web. Retrieved from

van Spronsen, F.J., van Rijn, M., Bekhof, J., Koch, R., Smit, P.G. (2001). Phenylketouria: tyrosine supplementation in phenylalanine-restricted diets. The American Journal of Clinical Nutrition, 73(2), 153-157. Retreived from

#thyroid #hypothyroidism #goitrogens #cruciferous #veggies #energy #metabolism


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Disclaimer: Any information on this website is for informational purposes only and are not intended to be used in place of professional medical advice.

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