Calcium is the most abundant mineral in the human body. Calcium promotes normal muscle contraction and blood vessel contraction and expansion. It is essential for transmitting electrical impulses throughout the nervous system and secretion of enzymes and hormones. According to the National Institute of Health Office of Dietary Supplements, 99 percent of calcium in the body is stored in the bones and teeth. Calcium levels are regulated by the parathyroid gland and vitamin D.
Parathyroid
The parathyroid glands are four small glands located behind the thyroid. Normal parathyroid glands are a mustard-yellow color and shaped like a grain of rice. They may occasionally be as large as a pea and still be normal, according to the Parathyroid.com website. The parathyroid glands regulate calcium levels in the body. When blood calcium levels get low, the glands release parathyroid hormone, or PTH, which transfers some calcium from the bones to the blood.
Vitamin D
Vitamin D is present in some foods and is also obtained through exposure to ultraviolent rays from sunlight and dietary supplements. Vitamin D controls calcium absorption in the stomach and maintains calcium and phosphate concentrations to promote normal bone formation.
Hyperparathyroidism
Hyperparathyroidism occurs when one of the parathyroid gland produces too much of the PTH hormone and leaves too much calcium in the blood. This condition is known as hypercalcemia. The most common cause of hyperparathyroidism is a tumor on one of the parathyroid glands. Parathyroid tumors are always benign, but their effects can cause damage to the body due to the high blood calcium. Other causes are parathyroid hyperplasia, or an excess of normal parathyroid cells, parathyroid cancer--which is rare, or Type I and II multiple endocrine neoplasia syndrome, which is also rare.
Hypercalcemia
Hyperparathyroidism itself has no symptoms and is usually only detected when a routine blood test reveals high calcium levels. Therefore, symptoms that do occur are hypercalcemic. These symptoms include joint pain, bone loss, abdominal pain or discomfort, muscle weakness, loss of appetite, excessive thirst or urination, constipation, nausea and vomiting, kidney stones and fatigue.
Diet/Supplementation
You get calcium mostly from dairy products, and some of the food you eat, as well as dietary supplements. However, eating too many calcium-rich foods or overdosing on calcium supplements rarely leads to hypercalcemia.
Stabilizing Calcium Levels
A parathyroidectomy, which involves removal of the diseased parathyroid, is the primary treatment option for hyperparathyroidism. However, drugs may be prescribed to lower calcium levels and build up bone density while a patient waits for his surgery.
References
- National Institutes of Health: Office of Dietary Supplements: Dietary Supplement Fact Sheet: Calcium
- Parathyroid.com: Parathyroid Gland Overview: Parathyroid Disease, Parathyroid Function: How Parathyroid Glands Work
- National Institutes of Health: Office of Dietary Supplements: Dietary Supplement Fact Sheet: Vitamin D
- University of Maryland Medical Center: Hyperthyroidism
