Edit: nevermind, it was posted 2 times already [1, 2].
Some interesting stuff here.
Is the article that talks about the miscalculation
There are loads of nutrients that technically compete for absorption, but generally it isn’t a concern unless you are taking a huge dose of one. Even then, it’s not like little dog is completely blocked. I’d have to look at the studies the above comment is referencing to determine how much of a concern it actually would be.
Even if taking both together was 30% less effective than taking them apart, in the context that getting people to take a single pill daily with regard to timing is hard enough, it’s still a overall win. That said, I would agree such a situation should be reflected on the label.
Let’s say it is 30%, there’s no way potential buyers, when they see ‘1000 IUs Vitamin D’ for example, will realize it actually means ‘700 IUs’.
So I don’t see how your comment makes sense.
No need to discuss absorption. Furthermore, the idea "taking D and K at the exact same time reduces the absorption of D" is unsubstantiated in medical research
Magnesium is very important cofactor for metabolism of Vitamin D (and many other things, it’s a cofactor involved with hundreds of enzymes and such), which people are also generally low on.
I think there may be another big cofactor or two, but they escape my offhand recollection.
(That is, if the original calculations are wrong, but the result usually works out, it might not be caught.)
"We call public health authorities to consider designating as the RDA ... around 8000 IU for adults"