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 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 2 forms of bone diseases that weaken bones.
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Vitamin D deficiency can be caused by:
Factors that may increase your risk of vitamin D deficiency 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 have:
You will be asked about your symptoms and medical history. A physical exam will be done.
Your bodily fluids may be tested. This can be done with blood tests.
Your bones may be tested. This can be done with bone tests.
Talk with your doctor about the best plan for you. Treatment options include:
To prevent vitamin D deficiency, take these steps:
National Celiac Association
Office of Dietary Supplements—National Institutes of Health
Allain TJ, Dhesi J. Hypovitaminosis D in older adults. Gerontol. 2003;49: 273-278.
American Academy of Dermatology. Position statement on vitamin D. American Academy of Dermatology website. Available at: http://www.aad.org/Forms/Policies/Uploads/PS/PS-Vitamin%20D.pdf. Updated November 14, 2009. Accessed November 7, 2017.
Dietary supplement fact sheet: vitamin D. Office of Dietary Supplements website. Available at: http://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Updated February 11, 2016. Accessed November 7, 2017.
Pfeifer M, Begerow B, et al. Vitamin D and muscle function. Osteoporosis Int. 2002;13:187-194.
Plotnikoff GA, Quigley JM. Prevalence of severe hypovitaminosis D in patients with persistent, nonspecific musculoskeletal pain. Mayo Clin Proc. 2003; 78:1463.
Tangpricha V, Pearce EN, et al. Vitamin D insufficiency among free-living healthy young adults. Am J Med. 2002;112:659-662.
Vitamin D deficiency in adults. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T113821/Vitamin-D-deficiency-in-adults. Updated October 9, 2017. Accessed November 7, 2017.
Wagner CL, Greer FR, American Academy of Pediatrics Section on Breastfeeding, American Academy of Pediatrics Committee on Nutrition. Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics. 2008;122:1142-1152.
Last reviewed November 2018 by EBSCO Medical Review Board Dianne Scheinberg Rishikof MS, RD, LDN Last Updated: 12/20/2014