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In this Article

• What are symptoms, signs, and health risks of vitamin D deficiency?
• What are causes of vitamin D deficiency?
• How is vitamin D deficiency diagnosed?
• What is the treatment for vitamin D deficiency?
• Vitamin D FAQs
• Patient Comments: Vitamin D Deficiency - Symptoms
• Patient Comments: Vitamin D Deficiency - Tests
• Patient Comments: Vitamin D Deficiency - Treatment
• Find a local Doctor in your town
• Vitamin D Deficiency Index

The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test. A level of 20 nanograms/milliliter to 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency.

Treatment for vitamin D deficiency involves getting more vitamin D -- through diet and supplements. Although there is no consensus on vitamin D levels required for optimal health -- and it likely differs depending on age and health conditions -- a concentration of less than 20 nanograms per milliliter is generally considered inadequate, requiring treatment.

Guidelines from the Institute of Medicine increased the recommended dietary allowance (RDA) of vitamin D to 600 international units (IU) for everyone aged 1-70, and raised it to 800 IU for adults older than 70 to optimize bone health. The safe upper limit was also raised to 4,000 IUs.

If you don't spend much time in the sun or always are careful to cover your skin (sunscreen inhibits vitamin D production), you should speak to your doctor about taking a vitamin D supplement, particularly if you have risk factors for vitamin D deficiency.

WebMD Medical Reference

SOURCES:

Institute of Medicine: "Dietary Reference Intakes for Calcium and vitamin D."

Office of Dietary Supplements, National Institutes of Health; "Dietary Supplement Sheet: Vitamin D."

Melamed M. Archives of Internal Medicine, August 2008.

News release, Peninsula Medical School News.

WebMD Health News: "Low Vitamin D Linked to Severe Asthma."

Garland C.F. Annals of Epidemiology, July 2009.

MedlinePlus: "25-hydroxy Vitamin D Test."

Harvard School of Public Health: "Vitamin D: How Much Is Enough?"

Reviewed by Kathleen M. Zelman, MPH, RD, LD on May 04, 2012

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