Thyroid health: Common problems linked to this ultra-important vitamin

You might already know that vitamin D works with calcium to keep your bones healthy.

But what about your thyroid?

Even if you eat a diet that contains plenty of vitamin D or take a vitamin D supplement, you might still have low levels of vitamin D.

Problems with your thyroid can lead to stubborn weight gain, thinning hair, constipation, brain fog, and even infertility. And there’s a strong link between low levels of vitamin D and thyroid disorders.

Scientists have known about the relationship between vitamin D and the thyroid for decades.


You can improve vitamin D absorption by eating fermented veggies every day to heal a leaky gut. The Veggie Culture Starter makes it easy and convenient to ferment vegetables at home.

For example, we know that:

  • Receptors for vitamin D and thyroid hormone look a lot alike.1
  • Receptors for vitamin D are found within the thyroid gland.2

These discoveries led scientists to explore how vitamin D fits into the overall picture of thyroid health. They found that low levels of vitamin D are linked to Graves’ disease, Hashimoto’s thyroiditis, and thyroid cancer.3

While this doesn’t mean that thyroid disease is caused by vitamin D deficiency—it does imply that vitamin D plays an important role in the overall health of your thyroid.4

Vitamin D Linked to Autoimmune Thyroid Troubles

Immune cells are loaded with receptors that are waiting to bind with vitamin D.

But what are they doing there?

Scientists found that vitamin D silences some inflammatory signals. It also makes the immune system more flexible, meaning it’s less likely to fall out of balance and into autoimmunity.

A recently published study looked at the impact of vitamin D deficiency in folks who are otherwise healthy. Researchers found that low levels of vitamin D are associated with a higher risk of thyroid antibodies—which are found in those with autoimmune thyroid disorders, like Graves’ disease and Hashimoto’s thyroiditis.5

While previous research had underscored the relationship between vitamin D deficiency and those with autoimmune thyroid disorders, this was the first study to look closely at the impact of vitamin D deficiency in healthy men and women.

Even when autoimmunity isn’t present, inflammation within the body can reduce levels of circulating thyroid hormones.6 Vitamin D stops inflammation and the expression of pro-inflammatory messages.7

2 ‘Hidden’ Reasons You Have Low Vitamin D

Even if you eat a diet that contains plenty of vitamin D or take a vitamin D supplement, you might still have low levels of vitamin D.

There are two major reasons for this:

  1. Leaky Gut – Vitamin D is a fat-soluble vitamin that is absorbed in the small intestine and in the presence of fat.8 A leaky and inflamed gut can interfere with absorption of vitamin D.
  1. Genetics – Vitamin D’s wide reach comes from its ability to bind to vitamin D receptors, which are found within immune cells—impacting the production of pro-inflammatory messages and regulating the balance of the immune system. Genetic polymorphisms, or slight differences in genes, can impact the proteins and enzymes that help the body use vitamin D. These slight genetic differences have been linked to Hashimoto’s and thyroid cancer.9,10

Support Your Thyroid and Get the Most Out of Vitamin D Supplements

If you need to supplement in order to boost levels of vitamin D, make sure you consume your supplements with foods that are rich in healthy fats, such as avocado or milk kefir. Also, keep track of calcium. Vitamin D is necessary for the absorption of calcium, but too much vitamin D or calcium from supplements can push blood levels of calcium beyond normal range.

Signs of excessive vitamin D and calcium toxicity include:

  • Constipation
  • Irregular heartbeat
  • Kidney stones
  • Nausea
  • Nervousness
  • Thirst
  • Weakness

You can naturally boost levels of vitamin D by incorporating cod liver oil and fatty fish—such as salmon and herring—into your everyday diet.

Getting rid of leaky gut can make a big difference in how your body absorbs vitamin D. To heal an inflamed gut, we recommend eating plenty of fermented vegetables. For full digestive support, take one packet of Digestive Care Multi with every meal.

What To Remember Most About This Article:

Most of us are familiar with how vitamin D partners with calcium to keep bones healthy, but what about vitamin D’s relationship with the thyroid? Researchers have discovered a strong link between low levels of vitamin D and thyroid disorders, known to cause symptoms like brain fog, constipation, hair thinning, weight gain, and infertility, in some cases.

You may be low on vitamin D and not even know it.

Even if you eat a vitamin D-rich diet and take a supplement, there are two often overlooked reasons for a common vitamin D deficiency:

  1. Leaky Gut – Since vitamin D is fat-soluble, it’s absorbed in the small intestine with the help of fat. A leaky gut can inhibit proper absorption.
  2. Genetics: Genetic variations can impact how enzymes and proteins in the body use vitamin D. These slight genetic differences are associated with thyroid cancer and Hashimoto’s thyroiditis.

There’s still hope if you’re struggling with vitamin D deficiency. You can take a supplement with healthy fats to improve uptake, like avocado or milk kefir. You can also address the root of the problem by healing a leaky gut that is inhibiting vitamin D absorption: Support daily gut health and strengthen the gut lining by eating fermented vegetables and taking a Digestive Care Multi packet at each meal.


  1. McDonnell, D. P., Pike, J. W., & O’Malley, B. W. (1988). The vitamin D receptor: a primitive steroid receptor related to thyroid hormone receptor. Journal of steroid biochemistry, 30(1), 41-46.
  2. Lamberg-Allardt, C., Valtonen, E., Polojärvi, M., & Stewen, P. (1991). Characterization of a 1, 25-dihydroxy-vitamin D 3 receptor in FRTL-5 cells. Evidence for an inhibitory effect of 1, 25-dihydroxy-vitamin D 3 on thyrotropin-induced iodide uptake. Molecular and cellular endocrinology, 81(1), 25-31.
  3. Muscogiuri, G., Tirabassi, G., Bizzaro, G., Orio, F., Paschou, S. A., Vryonidou, A., … & Colao, A. (2015). Vitamin D and thyroid disease: to D or not to D&quest. European journal of clinical nutrition, 69(3), 291-296.
  4. D’Aurizio, F., Villalta, D., Metus, P., Doretto, P., & Tozzoli, R. (2015). Is vitamin D a player or not in the pathophysiology of autoimmune thyroid diseases?Autoimmunity reviews, 14(5), 363-369.
  5. Sayki Arslan, M., Topaloglu, O., Ucan, B., Karakose, M., Karbek, B., Tutal, E., … & Delibasi, T. (2015). Isolated Vitamin D Deficiency Is Not Associated with Nonthyroidal Illness Syndrome, but with Thyroid Autoimmunity. The Scientific World Journal, 2015.
  6. POLL, T. V. D., ROMIJN, J. A., WIERSINGA, W. M., & SAUERWEIN, H. P. (1990). Tumor Necrosis Factor: A Putative Mediator of the Sick Euthyroid Syndrome in Man*. The Journal of Clinical Endocrinology & Metabolism, 71(6), 1567-1572.
  7. Kuo, Y. T., Kuo, C. H., Lam, K. P., Chu, Y. T., Wang, W. L., Huang, C. H., & Hung, C. H. (2010). Effects of Vitamin D3 on Expression of Tumor Necrosis Factor‐α and Chemokines by Monocytes. Journal of food science, 75(6), H200-H204.
  8. Dawson-Hughes, B., Harris, S. S., Lichtenstein, A. H., Dolnikowski, G., Palermo, N. J., & Rasmussen, H. (2015). Dietary Fat Increases Vitamin D-3 Absorption. Journal of the Academy of Nutrition and Dietetics, 115(2), 225-230.
  9. Tamer, G., Arik, S., Tamer, I., & Coksert, D. (2011). Relative vitamin D insufficiency in Hashimoto’s thyroiditis. Thyroid, 21(8), 891-896.
  10. Penna-Martinez, M., Ramos-Lopez, E., Stern, J., Hinsch, N., Hansmann, M. L., Selkinski, I., … & Badenhoop, K. (2009). Vitamin D receptor polymorphisms in differentiated thyroid carcinoma. Thyroid, 19(6), 623-628.
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