Thyroid Hormonal Balance
Vitamin D receptors (VDR) are present in the cells of the pituitary, the pea-sized gland located at the base of the brain that controls your thyroid. The pituitary produces a hormone called thyroid stimulating hormone (TSH) that signals your thyroid gland to make thyroid hormone (T3 and T4). Thyroid hormone constantly circulates throughout your body, regulating metabolism. Either inadequate or excessive thyroid hormone can wreak havoc to your health, culminating in hypo- or hyperthyroidism. Understanding the regulating effects of VDR in our cells, I surmise that the amount of activated vitamin D3 in the pituitary’s VDR may be connected to the balance of thyroid hormone.
Autoimmune Thyroid Diseases
Adequate levels of vitamin D3 may protect the immune system from attacking itself. Low vitamin D3 levels have been linked to autoimmune thyroid diseases including Hashimoto’s and Graves’ thyroiditis.
Discovered one hundred years ago by a Japanese physician, Hashimoto’s disease is caused by abnormal blood cells and white blood cells constantly attacking and damaging the thyroid. About 95 per cent of Hashimoto’s disease patients are women. A study published in a 2011 issue of the journal Thyroid revealed that 92 per cent of Hashimoto’s thyroiditis cases had insufficient circulating vitamin D3 levels.
Ten times more likely to develop in women than men, Graves’ disease is caused by antibodies that overstimulate thyroid hormone production, causing hyperthyroidism. Researchers, who investigated Japanese female and male patients with Graves’ disease over a one-year period, found a high prevalence of woefully low circulating vitamin D3 in the female patients compared to the male subjects.
Incidences of thyroid cancer have doubled over the past four decades. The likelihood of women developing thyroid cancer is three times greater than for men. Activated vitamin D3 regulates cell differentiation, cell proliferation, and cell death. If these vital functions go awry, cancer may develop. Epidemiological studies indicate a link between vitamin D3 and thyroid cancer. Vitamin D researcher W.B. Grant, Ph.D. published a paper in a 2012 issue of the journal Anticancer Research that indicated an association between solar ultraviolet B, vitamin D3, and cancers including thyroid.
A relatively rare form of thyroid cancer—medullary thyroid cancer—originates in the thyroid C cells where a hormone called calcitonin is secreted. Calcitonin’s functions include stimulation of vitamin D3 production in the kidneys. The measurement of calcitonin is a diagnostic screening tool for medullary thyroid cancer. VDR are present in the thyroid C cells. Understanding the powerful effect of activated VDR on cell regulation, I hypothesize that activated VDR in the C cells may possibly prevent the development of medullary thyroid cancer.
In conclusion, recent medical literature suggests a connection between vitamin D3 and thyroid health. However, additional research is required to determine if thyroid dysfunction may cause vitamin D3 deficiency, or low vitamin D3 status may contribute to thyroid disorders.
Copyright ©2012 by Susan Rex Ryan, all rights reserved.
This post was published previously on Hormones Matter in September 2012.