Your thyroid gland plays a major role in your body's metabolism. Thyroid hormones attach to thyroid-specific receptor sites on cells throughout your body. Like any other body part, the thyroid requires specific nutrients to run smoothly. Although vitamin D is not needed to make thyroid hormones, research has recently begun to see a link between low levels of vitamin D and thyroid function. Evidence is not concrete, and more data is needed; talk to your doctor about your thyroid and vitamin D levels.
Thyroid Gland
According to the University of Maryland Medical Center (UMMC), the thyroid gland is located on the front of the neck, just below the voicebox. It is a wing-shaped gland, with one lobe on each side of the neck. The thyroid uses iodine to create its active hormones, T4 and T3, which are produced by follicular cells. These hormones work throughout the body, stimulating every tissue to make proteins and increase the amount of oxygen used by cells. Parafollicular cells in the thyroid produce a hormone called calcitonin, which works with the parathyroid hormone to regulate calcium levels in the body. Thyroid hormone secretions are controlled by the brain via the thyroid stimulating hormone, or TSH.
Vitamin D
Vitamin D can be obtained through certain foods, like eggs and fish, as well as through exposure to UV light. According to the Mayo Clinic, it is a fat-soluble vitamin that is needed for maintaining blood levels of calcium and phosphorus. It actually helps the body to absorb calcium; thereby playing a large role in bone and muscle health. Vitamin D may also play a role in immunity and potentially protect against disorders like cancer and autoimmune diseases.
Thyroid Disorders
Recently, science has begun to investigate the potential link between vitamin D deficiency and impaired thyroid function. If thyroid hormone levels are imbalanced, or if the thyroid lacks nutrients to operate correctly, disorders can result. One common disorder is hypothyroidism. This disorder is characterized by low levels of active thyroid hormones, which can lead to weight gain, fatigue, poor sleep and sometimes depression. In contrast, hyperthyroidism is an excess of active thyroid hormones, which leads to weight loss and anxiety. Research is now indicating that low vitamin D may, in part, lead to hyperthyroidism.
Research
According to a report in the October 2009 "Endocrinology," vitamin D deficiency may influence thyroid function. The study states previous evidence had shown that vitamin D enhances regulatory T cells of the immune system. The study found that mice with vitamin D deficiency had lower T4 hormone levels and unexpectedly developed hyperthyroidism. Although this data shows a link between vitamin D and thyroid function, more evidence is needed before vitamin D can be considered an adjunct therapy for hyperthyroidism.
Thyroid Cancer
In addition to potential hyperthyroidism, lack of vitamin D may leave the thyroid more susceptible to developing cancer. In a study published in the "Archives of Medical Research" in April 2010, researchers compared vitamin D levels in patients with cancer vs. a control group of healthy patients. The results showed that the patients with thyroid follicular cell cancer had significantly lower levels of vitamin D. Although a link exists between vitamin D deficiency and potential thyroid cancer, vitamin D deficiency does not necessarily cause cancer of the thyroid gland. Talk to your doctor about your thyroid health before taking vitamin D.
References
- University of Maryland Medical Center: Thyroid Gland
- The Mayo Clinic: Vitamin D
- "Endocrinology"; Vitamin D Deficiency Modulates Graves' Hyperthyroidism Induced in BALB/c Mice by Thyrotropin Receptor Immunization; A. Misharin et al; October 2009
- "Archives of Medical Research"; Decreased 1-25 dihydroxyvitamin D3 concentration in peripheral blood serum of patients with thyroid cancer; T. Stepien et al; April 2010
