Keeping an Eye on Vitamin D Deficiency

There is mounting evidence that Vitamin D deficiency is problematic. Apparently, the only way to know for sure if you are deficient is by taking a test. A recent Outside Magazine article on Vitamin D deficiency cites a study from the Archives of Internal Medi­cine last year that says that approximately 77 percent of the U.S. population has “insufficient” levels of vitamin D. 

Why should you care? Most recently, CBS news reported that new research suggests vitamin D can raise the risk of dementia (Alzheimer’s) up to fourfold.  The Mayo Clinic site   says research indicates that vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases, not to mention rickets. Outside Magazine also cites studies that say Vitamin D enhances athletic performance.

While we Americans used to get most of our Vitamin D from the sun, The American Academy of Dermatology’s current stance is that no amount of unfiltered sun exposure is safe, given high rates of skin cancer. Moreover, many of us don’t get a great deal of sun time anyway because of where we live and/or how we work!  While there are several foods that provide vitamin D, like salmon and fortified milk, it may be hard to meet current minimum daily requirements without supplementation.

But wait! There is controversy about how much is enough or too much! On the other hand, there seems to be some agreement about how much Vitamin D should circulate in your body.  Several articles recommend that both adults and children measure above 50 ng/ml (125 nmol/L) year-round in their test results.    So, you can start there, with a doctor administered blood test, or a home test. Two sites recommend an easy-to-use, relatively painless do it yourself test available on line from ZRT Laboratory ($75;  called 25-hydroxyvitamin D test, also called a 25(OH)D. If you take a test and find you are below the recommended Vitamin D level then you can talk with your doctor about supplementing as needed. You can read more about ZRT test details from an organization called the Vitamin D Council, but be aware, they are citizens, (some  are doctors) not scientists.  

In the meantime, Adequate Intake (AI) levels established by the U.S. Institute of Medicine of the National Academy of Sciences are published as follows:

  • Males, females,  and pregnant/lactating women under the age of 50 years old: 5 micrograms (200 IU or “International Units”) daily
  • Individuals from 50-70 years-old: 10 micrograms daily (400 IU)
  • Over 70, 15 micrograms daily (600 IU)

But don’t overdo it!  More than 2,000 IU daily may lead to toxicity.  Sounds like we will all learn more in the next few years…and that it’s worth paying some attention to Vitamin D.

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Date: Tuesday, 13. July 2010 17:29
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  1. 1

    Vitamin D Council has two expert vitamin D scientists on our Board of Directors:

    Bruce W. Hollis PhD and William B. Grant PhD

  2. 2

    Thanks for the clarification! Your commitment to spreading the word is most appreciated.

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