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
in children. In adults, it can lead to
. 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: Inadequate intake of vitamin D in the diet
Lack of sunlight due to:
Having a darker skin colorWearing clothes that cover most of the skinLiving in northern latitudes during the winterNot being exposed to direct sunlight—Sunlight through windows, clothes, or sunscreen-covered skin is not enough for the body to synthesize vitamin D.
Conditions and procedures that affect the body’s ability to absorb vitamin D from the digestive tract (such as
inflammatory bowel disease
, bariatric surgery)
Conditions or medications that affect the process of converting vitamin D to a form that the body can use, such as:
Anti-seizure medicationsSevere liver diseaseChronic kidney diseaseVitamin-D dependant rickets (an inherited condition)Hypoparathyroidism
Risk factors include: Limited sun exposureDarker skin colorKidney diseaseRestricted activity, such as due to hospitalizationInjury due to a severe burnMalabsorption disorder, such as celiac diseaseObesityCertain types of diets, such as macrobiotic dietLiver conditionsBabies who are breastfed or do not consume enough formula that is fortified with vitamin D
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: Bone and muscle painMuscle weaknessHip painFracturesDifficulty walking, walking up stairs, and getting out of a chairFalls
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: Vitamin D supplementation—High doses of vitamin D are given for 6-12 weeks. This is followed by a lower dose of the vitamin. The doses are continued until blood levels return to normal.Calcium supplementation—Calcium plus vitamin D supplements may be given to increase D levels. This can also improve bone strength in older women with low vitamin D.Light therapy—Exposure to sunlight or UV radiation can increase D levels. Vitamin D3 is produced in the skin when it is exposed to these light sources.
To prevent vitamin D deficiency, take these steps: Eat a healthy diet. Foods are not naturally high in vitamin D. Many foods are enriched with vitamin D, such as milk, juices, and cereal.Take a vitamin D supplement if recommended by your doctor. Your baby may need a supplement if he is breastfed or does not consume enough formula that is fortified with vitamin D. Children may also need to take a supplement if they are not getting enough vitamin D in their diets.Follow your doctor’s guidelines on getting enough sun exposure.If you or a family member has any of the above risk factors, talk to the doctor about other ways to avoid becoming deficient in vitamin D.
Allain TJ, Dhesi J. Hypovitaminosis D in older adults.
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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:
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.
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Tangpricha V, Pearce EN, et al. Vitamin D insufficiency among free-living healthy young adults.
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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.
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.
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