Vitamin D is a fat-soluble vitamin. Fat-soluble vitamins are stored in the body's liver and fatty tissues. Vitamin D acts as both a vitamin and a hormone. Two of the main sources of vitamin D are food and sunlight. The ultraviolet rays of the sun react with cholesterol present on the skin and create previtamin D3. This compound goes through a series of reactions involving the kidneys and the liver. The final product is vitamin D.
Vitamin D deficiency describes low levels of vitamin D in the blood. This condition can lead to a condition known as rickets in children. In adults, it can lead to osteomalacia. These are two forms of bone diseases that weaken bones. It is important to contact your doctor if you think you have vitamin D deficiency.
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Vitamin D deficiency can be caused by:
Risk factors include:
Wearing sunscreen may be a risk factor for vitamin D deficiency. But, organizations like the American Academy of Dermatology (AAD) recommend that you use sunscreen to protect your skin from UV exposure, a known risk factor for skin cancer.
If your vitamin D deficiency is mild to moderate, you may not have any symptoms. If you have a severe deficiency, you may experience:
Your doctor will ask about your symptoms and medical history. Tests may include the following:
Talk with your doctor about the best plan for you. Treatment options include:
To prevent vitamin D deficiency, take these steps:
Celiac Sprue Association
Office of Dietary Supplements
Canadian Pediatric Society
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Last reviewed December 2013 by Peter Lucas, MD
Last Updated: 1/13/2014