It depends on your labs, for one, and on the type of A, D, or K for another. If you take a "dry A" that is mostly beta carotene post DS, you won't get a heck of a lot of actual vitamin A.....Oh crumb, and of course the reason for this (something about the anatomical changes) has fallen out of my head at this hour of the morning.
Vites that are rendered water soluble will get out of your system faster than their oil based "regular" versions, even though they are originally fat soluble. You can probably explain this part better than I can
, cuz you learned A&P for real.
It's really bizarre, I know, and your medically trained brain wants to just short circuit and blow up thinking about it, but it truly works this way. SOME people need relatively minimal supplementation, and other people can't budge a deficiency even with amounts of a supplement that would kill a normal person. My various B vites have been pretty stable for a while just with what I have in my multi (I take 4 Kirkland Daily Multis daily), as has my copper, but my zinc flies around like crazy even with an extra 200 mg (or is zinc in mcg?) daily. Damned stuff bottoms out this time of the semester no matter how much I take, it seems.....Maybe a stress correlation.
My A stays stable in midrange on 50K IU daily. If I miss even a few doses, I can promise you that my test results would be in the teens or single digits. (It goes back up pretty fast, though.) My D, on the other hand, can't be brought about 25 or so even on 200K IU dry D3 daily. I think my next trick will be to add rx D2 at high doses for a month or two and see what happens.
I can tell you from experience that it's a hell of a lot harder to bring up low levels than it is to cut back on large doses in the presence of high levels. Hence my advice is to start with more supplementation than you think you'll need and then adjust based on your own results.
One last thought: Put on your scientist hat and look at the studies, not just at articles like the ones you've linked. Where is the evidence to support those claims? (I don't know the answer because I didn't read the articles; this is a general statement.) Look at the studies that are cited, IF some are cited. Look at the research methods, results, etc. You know how to interpret a study, I'm sure. Do the cited studies REALLY support the claims in the article? If so, how solidly?
AND......Of these supposed horrible things that can happen with megadosing, how truly dangerous are they and how treatable are any symptoms/conditions that could arise? How long do you have to megadose to get them? Remember as well that if a study is done on humans, they are not DSers, therefore you cannot simply generalize the results to us as we are a special population.
If the above links are similar to others I've read over time, their citations will be to
in vitro studies anyhow, for the most part.
ETA: Oh FMR. I clicked on the Dummies link. What patent BULLSHIT. And not a single reference/citation in sight. C'mon Will, you know better than to believe that shit
. At least use the NIH site!