The Importance of Vitamin D

October 17th, 2010

By Cathie Dunal MD, MPH: The list of Vitamin D’s impact has expanded to both physical and psychological health:

    . Lower rates of colon, lung, breast, and prostate cancer and melanoma
    . Less risk for stroke and heart attacks
    . Less risk for allergies and autoimmune disease
    . Prevents osteoporosis, through its role in assisting calcium absorption
    . Better immunity—fewer colds and flu
    . Lower risk of Alzheimer’s
    . Improved mood
    . Lower rates of multiple sclerosis.  (However, this may be a false association because the lower rates are also associated with lower latitudes and more sun—it could be due to another component of sunshine.)

How much Vitamin D should you take?……….

I disagree with the idea that Vitamin D is a “one size fits all” requirement.  Vitamin D acts like a hormone in the body, and hormone requirements need to be customized.  (Doctors don’t prescribe the same dose of thyroid medicine to everyone, right?)

The bottom line—check your Vitamin D level. (Ask for a “25-OH Vitamin D level.”)  Then you need to take whatever dose your body needs to get to the target level.  (For most adults out of their 20’s, that is far more than a 400 IU “minimal daily requirement”—it’s usually at least 1000 or 2000 UI of Vitamin D3 a day.) The older you are, the more you need, because your skin becomes less efficient at converting your body’s pro-vitamin D into Vitamin D. (For very low levels, doctors prescribe an ultra-high weekly dose for about 3 months, to get you to the target level quickly.  You get better absorption with Vitamin D3, not D2.  Most large chain-store pharmacies have only D2, so get yours at a compounding pharmacy or a smaller pharmacy. (We often use Keefer’s in Mount Prospect—they send it out to you.)

Just what is the target level for Vitamin D?   We know that there are lower rates of colon cancer with levels of 75 to 100.  Lab results say that the “normal” range is 33 and above—but until recently, they used a lower limit of 20!  The old “normals” were based on population averages, and a population that is in the north, like that of the United States, is likely to be low, on average!  I disagree with the labs and recommended a level of 50 to 60—but in the light of this last research paper, I would aim for 75, especially if you have a family history of cancers.

At this point you may be asking why can’t you just get out in the sun?  First, there isn’t enough sun in the winter, October through April, if you are north of Atlanta (or south of Buenos Aires).  Second, the sun’s rays are more damaging now, with climate change, so you would increase your chances of skin cancer if you went out for longer periods without sunscreen.

(A note of caution—don’t give high doses of Vitamin D to children, whose bones are still growing.  If your child has a low level, I’m told that it’s safe to dose at most 2,000 IU a day.)

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