Vitamin D and Thyroid Health: Sunshine vs. Supplementation

Many of the people I consult with who have thyroid and autoimmune thyroid conditions are deficient in vitamin D.  25-hydroxy vitamin D is one of the standard serum tests I recommend, and I would estimate that about 80% of my patients come back deficient in this vitamin.  Some of these people live in areas where there is a lot of sunshine, and when someone gets a good amount of sun exposure they are frequently puzzled as to why their vitamin D levels are so low.  So the goal of this blog post is to discuss whether getting sun exposure is sufficient, or if supplementation with vitamin D3 (cholecalciferol) is necessary regardless of how much sun one gets.

But before I discuss this, I’d like to briefly talk about the reference range of vitamin D.  Most labs have a reference range between 30 and 100 ng/ml, although this will vary slightly with different labs.  Some labs have the upper limit as 80 ng/ml, but I’m going to focus on the lower end of the reference range.  30 ng/ml is usually sufficient for bone health, which is what most medical doctors are concerned about when looking at these levels.  However, for optimal immune system health the levels should be above 50 ng/ml.

Vitamin D and Autoimmune Thyroid Conditions

Numerous studies have demonstrated the importance of vitamin D with regards to  autoimmune thyroid conditions (1) (2).  Vitamin D modulates the immune system and plays an important role in the maintenance of immune system homeostasis (3).  I’m not suggesting that having sufficient vitamin D levels alone can restore the health of the immune system in people with Graves’ Disease and Hashimoto’s Thyroiditis.  However, I do believe that it is necessary to correct this deficiency for anyone who is looking to restore their health back to normal when following a natural treatment protocol.  After all, Graves’ Disease and Hashimoto’s Thyroiditis aren’t thyroid conditions, but instead are autoimmune conditions which affect the thyroid gland.

Of course the other vitamins and minerals play an important role in immune system health.  As a result, if someone has a deficiency in vitamin A, vitamin C, vitamin E, selenium, zinc, etc., then this will affect the health of the immune system.  So while I can argue that vitamin D is more important than these other vitamins and minerals with regards to immune system health, the truth is that all of these vitamins and minerals are important for optimal immune system health.  But of course the focus of this post is on vitamin D, and many other natural healthcare professionals agree with my perspective, as many will test all of their patients, regardless of whether they have an autoimmune thyroid condition or not.

Getting Vitamin D Through The Sun

Even though vitamin D is present in some of the foods we eat, vitamin D is supposed to be primarily synthesized from exposure to the sun.  I think that everyone should try to get regular sun exposure to help raise and then maintain their vitamin D levels.  With that being said, it can be difficult to get all of the vitamin D you need from the sun.

For example, some areas are better than others with regards to getting sun exposure.  Obviously states such as Florida and Arizona have more sunny days on an annual basis when compared to states such as North Dakota and Idaho.  Just being exposed to the sun isn’t enough, as if most of your body is covered up with clothing and/or you are wearing sunscreen then you are likely to be deficient in vitamin D, regardless of how much sun exposure you get on a regular basis.  Also, having darker skin or living in a higher latitude can also contribute to a vitamin D deficiency.

When Is Supplementation with Vitamin D3 Necessary?

There are numerous factors which can prevent someone from getting adequate sun exposure.  And even if they get a good amount of sun exposure, certain factors may still lead to a vitamin D deficiency.  As a result, when should someone supplement with vitamin D3?  Well, the first thing someone should do is get their vitamin D levels tested.  If their levels are above 50 ng/ml and they have accomplished this by getting regular exposure to the sun, then supplementation probably isn’t necessary.

On the other hand, if they get tested and have a moderate to severe deficiency, then what I recommend is to supplement with vitamin D3 to correct this deficiency, as it will be challenging to correct a deficiency by getting sun exposure.  Once they get their levels above 50 ng/ml (which should be confirmed with a follow-up test), then it might be feasible to maintain these levels through sun exposure alone.   However, in this scenario I usually will recommend for the person to remain on vitamin D3 until they have restored their health back to normal.

Once someone has restored their health back to normal I’m usually fine with them stopping vitamin D supplementation and then trying to maintain healthy levels through sun exposure.  I would then recommend for them to test these levels three to six months later to see if the levels are still fine.  If they still are above 50 ng/ml, then they probably don’t need to supplement with vitamin D3, although I would still have them obtain a 25-hydroxy vitamin D test at least once or twice per year.

On the other hand, if they can’t maintain healthy vitamin D levels through regular sun exposure, then they probably will need to supplement with at least 2,000 IU of vitamin D3 per day, and during the fall and winter months they might benefit from higher doses (up to 5,000 IU per day).  Another thing to keep in mind is that vitamin D needs other nutrients and cofactors in order to get absorbed (4).  A few of these nutrients include vitamin K, magnesium, vitamin A, and zinc.  So it’s important for people to eat well, and probably a very good idea to take a multivitamin with minerals to make sure they have these cofactors.

In summary, having a vitamin D deficiency is very common, and anyone who is deficient will most likely need to supplement with vitamin D3 in order to get the levels above 50 ng/ml.  Once someone has achieved this then they can try to maintain these levels through regular sun exposure, although I usually will have my patients continue supplementing with vitamin D3 until they have restored their health back to normal.  And you want to make sure that you’re not deficient in any of the cofactors which are necessary for the absorption of vitamin D3.