TcTrek,
I can't answer for Zen, but when my gynocologist was suggesting i get the vitD blood test, I said "So I get the usual 400mg in a daily multivitamin....if it turns out from the test that I'm deficient then I should maybe double or triple that for a while to like 800 or 1200mg?".....
and he answered- "No no, they are drastically rethinking the minimum daily requirement now to perhaps ten times what they thought people needed all these years, so you may see vitamins get readjusted to 4,000mg or more soon. But when I find my patient deficient i have her take 10,000 to 12,000mg per day for a few months, then go back to around 5-8,000 mg daily after that as a normal daily amount."

Needless to say, I was pretty amazed. But he is a smart and experienced women's doctor who's had thousands of patients over the decades, many of them older women with bone issues. I now make sure I ingest at least 4,000mg a day, but then again i don't have a D deficiency.
I also think it's important to try to balance your vitamins and minerals so that you are not taking a lot of one thing and hardly any of another thing that needs to work together with it. That's why I like to take fish liver oil that has both A&D naturally, calcium along with magnesium and the vitD, and vitC with riboflavinoids (sp?). I figure thats how lucky cavewomen would eat- stumbling upon wild fruits or fish and eating the whole complex shebang- peel, pulp, seeds, skin, organs, certain bones or marrow, liver, and all.

Hmmm.....maybe Mimi can grind me up some whole chickens!