Vitamin D and Thyroid Function

Vitamin D is all over the news these days. The press is full of information about the benefits of vitamin D supplementation and the various diseases that may result because of its deficiency. Besides playing an important role in bone formation, vitamin D deficiency has been linked to a higher susceptibility of immune disorders, including chronic infections and autoimmune diseases. Recently, it has been discovered that a deficiency in this important vitamin may also play a role in thyroid diseases.

Thyroid

Thyroid is a small endocrine gland located below the skin and muscles at the front of the neck, just below the Adam's apple. The thyroid hormones play an important role in regulating the metabolism of the body. They determine the growth and maturation of tissues, the body's use of different hormones and vitamins, and set the metabolic rate of our bodies. Both overproduction as well as under production of thyroid hormones is bad for your body. Overproduction of thyroid hormones can cause hyperthyroidism while their under production can lead to hypothyroidism and goiter.

Vitamin D

Vitamin D is a fat soluble vitamin synthesized on exposure to sunlight. Besides sunlight, vitamin D2 (ergocalciferol) can be derived from plant sources while vitamin D3 (cholecalciferol) can be obtained from animal sources. It is critical for the digestion and utilization of calcium and phosphorus by our body and plays an important role in bone formation. It is also important in infectious and auto immune disease, like tuberculosis and type 1 diabetes.

Vitamin D and Thyroid

People suffering from hypothyroidism may have low levels of vitamin D because of poor absorption from the gut. This, in turn, can lead to bone problems associated with hypothyroidism. Low levels of vitamin D have been implicated in the development of autoimmune diseases like Graves' disease and Hashimoto's thyroiditis. Therefore, proper vitamin D supplementation is essential in patients suffering from thyroid diseases. All thyroid patients are encouraged to have a screening for vitamin D deficiency.

Vitamin D deficiency can lead to autoimmune diseases of the thyroid. A study published in the May 2011 issue of "Cellular and Molecular Immunology" compared the levels of vitamin D in patients of autoimmune thyroid diseases (AITDs) to those in non-AITDs healthy people. Significant vitamin D deficiency was found in patients with AITDs and Hashimoto's thyroiditis. Vitamin D deficiency could also be correlated to the presence of anti-thyroid antibodies and abnormal thyroid function tests. The results suggested the involvement of vitamin D in the pathogenesis of AITDs and the role of its supplementation in such patients.

References:

http://amjpathol.highwire.org/cgi/content/full/160/2/511

http://www.ncbi.nlm.nih.gov/pubmed/21278761

http://www.ncbi.nlm.nih.gov/pubmed/20427238