Vitamin D Deficiency And The Thyroid

Vitamin D Deficiency And The Thyroid

Vitamin D Deficiency And The Thyroid

The connection between a Vitamin D deficiency and thyroid disease is gaining interest in the medical world. More and more research is becoming evident showing links between the two.

First, let’s discuss the role of Vitamin D in the body and why it is critical for our health.

The Role of Vitamin D

Vitamin D is more of a hormone than simply put “a vitamin.” It’s a fat soluble vitamin meaning that it gets stored in our bodies. As most of us know, it helps our body absorb calcium and phosphorus which keeps our bones healthy and in tact.

Evidence shows that Vitamin D also helps reduce cancer cells, support the immune system and reduce inflammation (1). What is interesting though, is that many organs and tissues have Vitamin D receptors. This illustrates to us that Vitamin D has important roles throughout the whole body.

How To Get Vitamin D

You may have heard Vitamin D to be the “sunshine Vitamin.” Direct, yet safe exposure to sunlight everyday is one of the best ways for the human body to absorb Vitamin D. Very few foods actually contain Vitamin D and a number of commercial foods will fortify products with Vitamin D. Here are ways you can increase your Vitamin D consumption (best sources first):

  • Sunlight
  • Fatty fish (salmon, cod liver oil, tuna, sardines)
  • Beef liver
  • Egg yolks
  • Fortified cereals
  • Fortified dairy and plant milks
  • Plants and fungi

Vitamin D2 vs. Vitamin D3

Simply put, Vitamin D3 is the active form whereas Vitamin D2 is the inactive form. The body will need to convert Vitamin D2 to Vitamin D3 in the liver and kidneys. This is another reason why liver health is so important. Most people with thyroid diseases have overburdened livers where T4 cannot effectively convert to the active form T3. Sluggish livers also indicate a re-circulation of toxins which can increase overall inflammation and activate an immune response (which is even worse for those with autoimmune conditions, like Hashimoto’s or Grave’s disease).

When the body absorbs Vitamin D via sunlight, it gets stored in the fat cells. When the body needs it, it starts its conversion process in the liver from the inactive form to the active form where it will be ready to use.

Vitamin D and the Thyroid

Studies have shown a direct link between Vitamin D deficiency and those with hypothyroidism and/or Hashimoto’s. The results show that those with hypothyroidism had a Vitamin D deficiency (and decreased calcium levels) and after carefully monitored supplementation, Vitamin D levels were restored as well as were optimal TSH levels.

Vitamin D has specific Vitamin D Receptors (VDR) that it binds to in order to be used properly by the body. Thyroid hormone and Vitamin D bind to similar receptors called steroid receptors. A different gene (polymorphism) in Vitamin D receptors has been shown to predispose people to autoimmune thyroid disease; both in Grave’s disease and Hashimoto’s thyroiditis.

Vitamin D receptor gene polymorphisms and Vitamin D deficiency(1) has a direct connection to thyroid disease and various autoimmune disease which encourages further research to see if a Vitamin D deficiency can be a cause that leads towards autoimmunity and/or contribute to the development of.

Vitamin D and Hashimoto’s

Vitamin D supplementation for those with Hashimoto’s is a common supplement endocrinologists will give patients due to its evidence on decreasing TPO antibodies (2). Although Vitamin D supplementation can be very helpful, it is still important to address the immune reaction, support the gut and follow a full thyroid healing protocol to prevent Hashimoto’s flare ups and progression.

Vitamin D shows a positive effect on both immune system control (improving the severity of Hashimoto’s by decreasing TPO antibodies) as well as improving thyroid health (by decreasing TSH levels in hypothyroid patients).

Thyroid Disease and Vitamin D Deficiency

If you are getting ample exposure to sunlight and/or are taking Vitamin D3 supplementation and are still deficient, there are 2 potential causes for this:

  1. Poor absorption through the small intestine.
  2. Poor activation.

When it comes to digestion and mealtime habits, you may find this article helpful.

Moving Forward

If you aren’t sure what’s going on with your thyroid or how to address it, please book a free phone consultation with our practitioner. You can schedule your call here, today!



  1. Mackawy, A. M., Al-Ayed, B. M., & Al-Rashidi, B. M. (2013). Vitamin d deficiency and its association with thyroid disease. International journal of health sciences, 7(3), 267–275.
  2. Chaudhary S, Dutta D, Kumar M, Saha S, Mondal SA, Kumar A, Mukhopadhyay S. Vitamin D supplementation reduces thyroid peroxidase antibody levels in patients with autoimmune thyroid disease: An open-labeled randomized controlled trial. Indian J Endocrinol Metab. 2016 May-Jun;20(3):391-8. doi: 10.4103/2230-8210.179997. PMID: 27186560; PMCID: PMC4855971.


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