Vitamin D Affects 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.