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.
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:
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:
Celiac Sprue Association
Office of Dietary Supplements—National Institutes of Health
Canadian Pediatric Society
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 December 22, 2014.
Dietary supplement fact sheet: vitamin D. Office of Dietary Supplements website. Available at: http://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Updated November 10, 2014. Accessed December 22, 2014.
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 website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated October 26, 2014. Accessed December 22, 2014.
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 December 2014 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.