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Old 04-05-2010, 05:44 PM   #41
Pie
Gone and done
 
Join Date: Sep 2001
Posts: 4,808
Quote:
Originally Posted by skysidhe View Post
Our lack of sunshine or the use of sunscreen makes us deficient in vitamin D?

The old saying that lots of sunshine and fresh air makes us healthy probably has to do with absorbing vitamin D.
It's the quantity of sunshine that's a problem. Most days/weeks, we don't get enough. Then we go waaaay overboard when we go on vacation and bake for hours on the beach, leading to pre-cancerous genetic damage to our skin.

10-15 minutes per day is enough to synthesize colecalciferol from its precursor molecule, 7-dehydrocholesterol. Alternatively, one can take oral colecalciferol supplementation.

It is interesting to note that neither D3 or D2 are biologically active in their own right; they are both metabolized in the liver and kidneys to the active form.
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