Vitamin K and Thyroid Health

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Vitamin K and Thyroid Health

Our thyroid gland is an important body organ that takes part in maintaining multiple body functions.

Multiple vitamins and nutrients are necessary for a healthy thyroid to function properly. One of these nutrients is Vitamin K. While relationship between Vitamin K and our thyroid gland requires more research, what we do know so far tells us about the several ways that Vitamin K and the thyroid gland work to maintain each other’s health and function.

Read on to find out more about the importance of Vitamin K for our thyroid health.

The health benefits of Vitamin K

Vitamin K got its name after its discovery was first reported in a German scientific journal where it was decided that this new vitamin would be called “Koagulationsvitamin.”[i]

Vitamin K belongs to the group of fat-soluble vitamins.

There are two main forms of Vitamin K known to men – Vitamin K1 and Vitamin K2. Other types of Vitamin K are found in nature as well, but these two are considered to be the most common ones found in the human body and diet.

Vitamin K1 is extracted from plant-based sources such as leafy green vegetables, such as kale, spinach, parsley, chard, romaine lettuce, etc. On the other hand, Vitamin K2 is extracted from animal-based sources, including fish, liver, egg yolks, cheese, and many more.

Vitamin K1 and K2 both have multiple important functions in our bodies. Most of us know them primarily for their involvement in the blood coagulation process. [ii]

Of the two, Vitamin K1 is more involved in the process of blood coagulation, while Vitamin K2 is more involved in maintaining our bone health. [iii]

Vitamin K is also involved in preventing cardiovascular disease from developing. Thanks to Vitamin K, no excess calcium is deposited inside the arteries, which if it did occur, could lead to multiple cardiovascular issues including high blood pressure, cardiac hypertrophy, aortic stenosis, etc.[iv]

Vitamin K also makes sure that our brain functions properly as well.[v] Science suggests that Vitamin K has the ability to slow down the cognitive decline that happens with the aging process, but also reduce the risk of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease.[vi]

The dangers of Vitamin K deficiency in the body

The biggest potential risk of severe Vitamin K deficiency in the body is excessive bleeding, caused by even the smallest injury imaginable.

If there is a Vitamin K deficiency present, then our cardiovascular health is at risk as well – the risk of calcium being deposited inside the arteries is higher, which could ultimately cause cardiovascular issues to occur.

Vitamin K deficiency can also lead to osteoporosis and calcification.[vii] Other health risks are expected to occur as well due to a Vitamin K deficiency.

The most obvious reason for a Vitamin K deficiency is, of course, a poor diet that fails to introduce the required daily amounts of Vitamin K. Gallbladder issues and certain medications, such as antibiotics, could affect the absorption of the fat-soluble vitamins as well.[viii]

The link between Vitamin K and thyroid health

Now let’s discuss how Vitamin K and thyroid health are related.

There are a couple of ways worth mentioning that link Vitamin K and the thyroid gland.

As we discussed, Vitamin K improves the absorption of calcium in the digestive tract.[ix] But why is that any relevant regarding our thyroid health?

Patients with hypothyroidism have been shown to struggle with calcium deficiency at the same time. It has also been revealed that as soon as the calcium deficiency has been properly treated, the symptoms of hypothyroidism could efficiently improve. However, this connection requires more research. Hypothyroidism patients are advised to watch over their use of calcium supplementation. [x]

Vitamin K has been researched to improve calcium absorption and thus could help with calcium deficiency and in turn hypothyroidism symptoms.

In addition, Vitamin K2 has been suggested to reduce the levels of what is known as thyroid-suppressive parathyroid hormone (PTH).

The PTH, as the term suggests, suppresses the production and secretion of the thyroid hormones in the bloodstream. This is the normal function of the PTH, but in some cases, the PTH can overact, suppressing the production and secretion of the thyroid hormones more than what is needed, which could result in a case of hypothyroidism.

Lastly, Vitamin K also helps activate Vitamin A and Vitamin D, both of which are important for maintaining our thyroid health.

On the other hand, the thyroid gland can impact Vitamin K as well. According to scientific research published in the International Journal of Immunopathology and Pharmacology, thyroid hormones, in addition to the other hormones of the hypothalamic-pituitary-thyroid axis (thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH)), affect the Vitamin K dependent plasma factors of coagulation.[xi]

Without these coagulation factors, blood coagulation would not be possible.

Low thyroid hormone levels bring you closer to the inability for your blood to coagulate normally, which exposes you to various health dangers that we have discussed earlier.

Accordingly, there has been a proper scientific study that confirms the findings of the risk of Vitamin K deficiency and blood coagulation issues that every hypothyroidism patient faces during his/her lifetime. [xii]

Another scientific research published in 2011, showed that the blood coagulation efficiently had improved after healthy individuals have received levothyroxine, due to the improvement in their blood coagulation factors levels and inhibited fibrinolysis. [xiii]

This only confirms that the thyroid gland has a certain impact on the blood coagulation factors.

On the other hand, those who have been struggling with hyperthyroidism can potentially worsen their symptoms with over-supplementation of Vitamin K. Due to the excess thyroid hormones that are already being produced within these patients, they are exposed to the risk of increased coagulation factors as well.

That can only lead to the potential risk of thrombosis, which as you probably know, is potentially life-threatening.

Supplementing with Vitamin K for thyroid health

Vitamin K is an important fat-soluble vitamin that our bodies are able to produce on their own. However, it is still recommended to test for Vitamin K levels and use proper supplementation if necessary as well as introducing Vitamin K rich sources into our diets.

As for patients struggling with thyroid issues, the use of Vitamin K supplementation is a bit controversial. Some scientific studies do suggest it could be helpful. But this is still an issue that needs to be discussed with your doctor.

As for patients struggling with hyperthyroidism, due to the potential risk of thrombosis, they are advised against using any Vitamin K supplementation. However, once again, your doctor is the only one that can determine whether or not Vitamin K supplementation should be used in your unique case. Thyroid supplements do not often include Vitamin K, as seen in Thyroid Advisor’s complete guide to thyroid support supplements.


Vitamin K is just one more essential vitamin that helps preserve our good health, including the health of our thyroid gland. Vitamin K helps our thyroid gland to stay healthy and our thyroid gland makes it possible for the blood coagulation process to go smoothly.

If you are considering using Vitamin K supplementation, consult your doctor as there are risks involved for certain thyroid disorders. Because of this, thyroid support supplements, such as those featured on this site, do not include Vitamin K in their ingredients.


[i] Newman P., & Shearer, M. J. (n.d.). Vitamin K Metabolism. Fat-Soluble Vitamins, 30, 455-488. doi:
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[ii] Gröber, U., Reichrath, J., Holick, M., & Kisters, K. (2014). Vitamin K: An old vitamin from a new perspective. Dermato-Endocrinology, 6(1). doi:10.4161/19381972.2014.968490

[iii] Vermeer, C. V. (2012). Vitamin K: The effect on health beyond coagulation – an overview. Food & Nutrition Research, 56(1), 5329. doi:10.3402/fnr.v56i0.5329
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[iv] Demer, L. L., & Tintut, Y. (2008). Vascular Calcification. Circulation, 117(22), 2938-2948. doi:10.1161/circulationaha.107.743161
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[v] Ferland, G. (2013). Vitamin K and Brain Function. Seminars in Thrombosis and Hemostasis, 39(08), 849-855. doi:10.1055/s-0033-1357481
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[vi] Presse, N., Belleville, S., Gaudreau, P., Greenwood, C. E., Kergoat, M., Morais, J. A., Ferland, G. (2013). Vitamin K status and cognitive function in healthy older adults. Neurobiology of Aging, 34(12), 2777-2783. doi:10.1016/j.neurobiolaging.2013.05.031
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[vii] Pearson, D. A. (2007). Bone Health and Osteoporosis: The Role of Vitamin K and Potential Antagonism by Anticoagulants. Nutrition in Clinical Practice, 22(5), 517-544. doi:10.1177/0115426507022005517
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[viii] Laukkarinen, J., Sand, J., Saaristo, R., Salmi, J., Turjanmaa, V., Vehkalahti, P., & Nordback, I. (2003, March). Is bile flow reduced in patients with hypothyroidism? Retrieved from

[ix] Iwamoto, J., Yeh, J., Takeda, T., & Sato, Y. (2005). Effects of Vitamin K2 Administration on Calcium Balance and Bone Mass in Young Rats Fed Normal or Low Calcium Diet. Hormone Research in Paediatrics,63(5), 211-219. doi:10.1159/000085681
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[x] Oregon State University. Vitamin K
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[xi] Negrev, N., Radev, R., Velikova, M., & Anogeianaki, A. (2008). Effects of the Hormones of the Thyroid Axis on the Vitamin K-Dependent Plasma Factors of Blood Coagulation (II, VII, IX, and X). International Journal of Immunopathology and Pharmacology,21(1), 221-226. doi:10.1177/039463200802100125
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[xii] Squizzato, A., Romualdi, E., Büller, H., & Gerdes, V. (2007). Clinical review: Thyroid dysfunction and effects on coagulation and fibrinolysis: A systematic review. The Journal of Clinical Endocrinology and Metabolism,92(7).
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[xiii] Zaane, B. V., Squizzato, A., Debeij, J., Dekkers, O. M., Meijers, J. C., Zanten, A. P., Brandjes, D. P. (2011). Alterations in coagulation and fibrinolysis after levothyroxine exposure in healthy volunteers: A controlled randomized crossover study. Journal of Thrombosis and Haemostasis,9(9), 1816-1824. doi:10.1111/j.1538-7836.2011.04430.x
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