Originally Posted by tandoorichicken
I think the number is actually 8000 IU (missed a zero). The old recommendations used to be below 5000. I've read that 15 minutes of sun exposure (maybe 20-30 at high latitudes) generates 10,000 IU and dumps it directly into the blood stream. Funny that...
It's still important to get D through diet though, as it facilitates calcium and magnesium absorption in the gut. D in the blood might be good for other things (mood, cellular health, metabolism), but it does nothing for mineral absorption.
I'm looking at my vitamin bottles right now and it says that the US RDA is 400 IU's for vitamin D, the note my doc wrote was for 800 IU's daily. So I'm not sure now.