Vitamin D is an important nutrient for many of the body's functions. Primarily, vitamin D helps in the absorption of calcium from the intestines and to maintain appropriate levels of calcium and phosphorus in the blood stream. These two minerals are the building blocks for the body's skeleton, so vitamin D is important for bone mineralization, growth and healing. There are several causes of vitamin D deficiency. One of the most important causes is a problem with PTH, or parathyroid hormone, a part of the endocrine system.
Vitamin D and Calcium
Vitamin D is synthesized in the skin due to sun exposure and is also ingested in the foods you eat, particularly dairy products and fortified foods, like breakfast cereals and juices. According to the book "Endocrinology: An Integrated Approach," vitamin D precursors must go to the kidney to become activated. Once active, vitamin D stimulates the absorption of calcium from the gut. The parathyroid glands increase calcium indirectly by its actions on vitamin D.
Parathyroid Hormone and Vitamin D
The main hormone that affects vitamin D levels in the body is the parathyroid hormone. The parathyroid glands, a set of four glands embedded within the thyroid tissue, are the main regulators of calcium and phosphorus in the body. According to Colorado State University, when the parathyroid gland senses a decrease in the level of calcium, it increases its secretion of parathyroid hormone. The parathyroid hormone acts on the kidneys to stimulate the activation of vitamin D, which then works to increase the level of calcium in the bloodstream.
Parathyroid Dysfunction and Vitamin D Deficiency
If the parathyroid glands are unable to secrete parathyroid hormones in response to low calcium levels, the activation of vitamin D in the kidneys decreases, which can then lead to vitamin D deficiency. The most common cause of decreased parathyroid function is the removal of the parathyroid glands during surgery to remove a hyperactive thyroid gland. Certain autoimmune conditions, in which the body attacks its own tissues thinking they are foreign, can also result in decreased parathyroid function.
Symptoms of Vitamin D Deficiency
The symptoms of vitamin D deficiency include rickets in children and osteomalacia in adults. According to the National Institutes of Health's Office of Dietary Supplements, rickets results in poor mineralization of bone, leading to weak and deformed bones that can fracture easily. Osteomalacia results in weak bones, bone pain and muscle pain and weakness.
Member Comments