“According to a 2009 report published in the Archives of Internal Medicine, 77% of Americans have a deficiency in vitamin D levels, affecting their overall health,” explains New York City-based registered nurse Rebecca Park.
“Vitamin D deficiency results from lack of exposure to sunlight (for example: if you live in the northern hemisphere, [cover up with clothing, or simply avoid the sun and wear sunscreen]), impaired vitamin D absorption [due to a medical condition], medications that impair vitamin D absorption, and low dietary intake,” added Dr. Shainhouse. “Individuals at highest risk are those who are institutionalized, the elderly, or those with more darkly pigmented skin.”
Park added that people over the age of 50 have less ability to synthesize vitamin D from sunlight and are at a greater risk of osteoporosis and arthritis, fractures, muscle weakness, and cancers.
“Testing for Vitamin D deficiency involves a simple blood test,” said Dr. Shainhouse. “The lab should measure the level of bioavailable vitamin D, which is D3 (the type that the skin makes). There is a range of normal, low normal, moderate and severe deficiency.”
Your doctor can test you annually.