How Vitamin D Affects Thyroid Conditions

Vitamin D is well-known for its importance in managing calcium in the gut, bones, and blood and disease resistance. However, many studies now show vitamin D levels affect may be a contributing factor in many other health issues too.

Researchers now believe it plays a crucial role in how cells communicate. Clinical studies link abnormal vitamin D levels to colon, prostate, and breast cancer as well as heart disease, weight gain, and thyroid conditions.

Vitamin D Production

Vitamin D is unique compared to other vitamins, because it is nearly impossible to get what you need from food. Instead, your body produces it naturally in the skin when you’re exposed to natural or artificial UVB light.

Once your body produces vitamin D or you take it as a supplement, it’s sent to the liver. The liver transforms vitamin D into 25(OH)D and sends it various areas of the body and activates it. Once activated, it is ready to perform its duties.

Autoimmune Conditions

Autoimmunity occurs when the immune system treats a person’s healthy tissues and cells as a threat. When this happens, their body produces an immune response and attacks. This response can cause damage, inflammation, and chronic pain in many parts of the body.

Vitamin D deficiencies may reduce the body’s ability to fight infection and may link to or cause autoimmune diseases such as Hashimoto’s Thyroiditis and Grave’s Disease.

Clinical Studies

Several 2014 studies presented at the annual meeting of the Thyroid Association are of special interest. Researchers from Nanjing, China evaluated 34 patients with Hashimoto’s Thyroiditis and 32 with Grave’s Disease against 52 healthy patients. Researchers measured many thyroid-related factors including vitamin D3.

Vitamin D is actually a group of compounds classified vitamin D1, D2, and D3. Vitamin D3 is the naturally occurring form of the vitamin, and the most biologically active.

Researchers found patients with autoimmune thyroid disease had significantly lower vitamin D3 levels than the healthy controls. Patients with high thyroid peroxidase antibodies the body produces in thyroid autoimmune disease also had lower vitamin D levels. This suggests vitamin D insufficiency could link to or cause autoimmune thyroid disease.

Brazilian researchers studied 54 Hashimoto’s patients, compared to 54 healthy controls. They also found vitamin D deficiency in 63.2% of the patients. Those with low vitamin D levels also had higher thyroid-stimulating hormone levels and a larger thyroid.

Lack of Vitamin D

Normally, the skin produces sufficient vitamin D when exposed to adequate UV light. However, the risks of skin cancer or melanoma now mean many people use sunscreen and cover their bodies. We also spend more time indoors for work and entertainment.

Since more clinical tests show a link between vitamin D and thyroid function, many physicians now recommend vitamin D testing as part of thyroid evaluation and care. Nonetheless, functional practitioners and doctors following the medical model may treat you differently based on your results.

Medical Model vs Functional Model

The medical model recommends 400 International Units per day of vitamin D. They also define a sufficient serum 25(OH)D level as over 50 nmol/L as it “covers the needs of 97.5% of the population”. The test used to measure vitamin D levels in the 25-hydroxy vitamin D blood test.

The medical model usually recommends supplementation to increase low vitamin D levels. However, the functional approach to care recognizes multiple reasons may cause low vitamin D levels. Consequently, recommending supplements before looking at overall health and other possible issues can be ineffective and counterproductive.

Supplements don’t always correct low vitamin D levels, because they do not address underlying problems. The vitamin D receptor in some autoimmune patients cannot activate due to variations in their DNA sequence. Consequently, they need higher than normal blood levels of vitamin D to avoid vitamin D insufficiency.

Vitamin D is fat soluble, and some patients with thyroid issues like Hashimoto’s thyroiditis have low stomach acid and poor fat absorption. Autoimmune conditions such as Hashimoto’s thyroiditis and Grave’s disease also make the immune system work overtime, which depletes the body’s stores of vitamin D. Therefore, addressing gut and digestive issues and modulating the immune system are of primary importance before considering vitamin D supplementation.

A highly qualified functional practitioner will look at your gut and digestive health and if they’re satisfied, they may order a 25-hydroxy vitamin D blood test for your vitamin D levels.

Your practitioner may recommend supplementation to reach between 60 and 80 nmol/L. This is still well below the 125 nmol/L threshold where a patient might experience adverse effects. After several months, they’ll retest. If their serum level rose to an acceptable level, the doctor will adjust vitamin D intake so serum levels stay between 50 and 60 nmol/L.

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Vitamin D insufficiency is just one factor that can contribute to thyroid problems, so self-supplementation is not recommended as it can be ineffective if underlying problems remain. Discuss your thyroid issues with a functional practitioner to develop an effective treatment protocol.