While there is a strong relationship between hypoparathyroidism and vitamin D levels, it is not necessarily one of vitamin D deficiency. Hypoparathyroidism causes low levels of calcium, and vitamin D plays a critical role in calcium metabolism. Consequently, the standard treatment for hypoparathyroidism includes vitamin D supplementation. The idea is to maximize calcium absorption rather than treat vitamin D deficiency. If you're considering supplementing for thyroid problems, it is essential that you discuss the issue with your doctor.
About Hypoparathyroidism
Hypoparathyroidism is a relatively rare disorder that affects the parathyroid glands. The most common cause is accidental damage or removal of the parathyroid during surgery, although the disorder is also associated with hereditary factors, autoimmune diseases and magnesium deficiency. A damaged parathyroid results in abnormally low calcium levels in the body which, if left untreated, can lead to kidney failure, heart arrhythmia, and death. The goal of treatment is to restore normal calcium levels and includes lifelong supplementation both of calcium and vitamin D.
Parathyroid Glands
Your parathyroid glands are responsible for regulating blood levels of calcium. Proper calcium levels are so critical to life support that the parathyroid does a minute-by-minute check of the levels. When they fall too low, the parathyroid secretes parathyroid hormone, or PTH. PTH travels to your bones and releases small amounts of calcium until levels are back to normal. This is where vitamin D fits into the picture. Vitamin D is needed to metabolize calcium; otherwise it remains inert and is excreted in urine.
Vitamin D Synthesis
Vitamin D goes through three steps of synthesis before it reaches the biologically active form needed to metabolize calcium. The process begins when cholesterol in your skin reacts with sunlight and the metabolite travels to the liver for conversion into the circulating form. The circulating version travels to the kidney where it's transformed into hormonal vitamin D, which is the biologically active form. This final version is critical to calcium metabolism and signals the intestines to absorb calcium while helping to regulate serum levels. A comprehensive accounting is reported in the September 2006 issue of "Progress of Biophysics and Molecular Biology."
Vitamin D Deficiency
People who suffer from hypoparathyroidism are generally well-served by taking lifelong supplementation both of the circulating and hormonal versions of vitamin D in addition to calcium supplementation. The therapy ensures adequate amounts of each nutrient to sustain health. However, few studies have examined vitamin D deficiency in relation to hypoparathyroidism. To shed light on the question, researchers reporting in the November 2001 issue of "Age and Aging" tested vitamin D levels in 150 elderly patients with hip fractures. They found that 68 percent were vitamin D deficient, and that half of these also suffered from hypoparathyroidism.
References
- MayoClinic.com: Hypoparathyroidism
- Colorado State University: Hypertext Medical Books: Endocrine System
- "Progress of Biophysics and Molecular Biology"; Vitamin D Physiology; P. Lips; September 2006
- "Age and Aging"; Hypovitaminosis D and 'Functional Hypoparathyroidism' the NoNoF (Nottingham Neck of Femur) Study; Opinder Sahota, et al.; November 2001
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