Vitamin D test instructions

[katromic]

Having heard about the potential benefits of Vitamin D3 supplementation, about 6 months ago I started taking 4000IU daily, but have never had a Vitamin D test.  My employer's wellness program is now offering free vitamin D testing to employees, and I want to make sure the test is accurate.  Should I discontinue taking vitamin D supplements in preparation for a vitamin D test?  If so, how long before the test?

[Renee Radenberg]

You should not go over in supplementation. 2000 IU is the tolerable upper intake level for adults; supplementation over that may cause a risk for toxicity (weak muscles, weak bones, excessive bleeding, and kidney stones). Vitamin D is available through our foods - Fortified milk, breakfast cereals, egg yolks, fatty fish, and fish oils. Sit at a window with the sun shining in for about 1/2 hour (few times a week) and that will help you get enough Vitamin D. Suggest lowering you supplementation.

[Renee Radenberg]

Sitting by a window, in the sun will not give you the amounts of vitamin D as if you were in the sun without the window, however, the combination of eating Vitamin D rich foods and sitting by a window (helps a little) will give you the Vitamin D your body needs. People who do not get outside or unable to go outdoors, a sunny window is the next best thing for them. It is better than not at all.

[arwright]

Hi Dr. *********,

Sorry to be contradictory, but according to my reading on the topic glass blocks the UVB rays needed to create vitamin D in your skin.

Sitting at an *open* window may be somewhat helpful, but sitting at a closed window, or anywhere where glass is between the sun and your skin, is not likely to help.  

I was disappointed to learn this -- having spent a lot of time lying in the sun from a picture window in my house -- but I realized that it's better to understand that such practices aren't going to help vitamin D status than to reside in a false sense of security on that point.