I hope the reader can access this article. Basically, it says that Vitamin D is overblown, massively, 100 fold over 10 years and for no good reason.
It sounds like you have to be very careful at or above 4000 Iu a day, and probably scant evidence it does any good. It increases risk of kidney stones, kidney disease, and does not really reduce risk of fractures and might increase risk of falls.
It is sad news for all the Vit D people, but his is a good study, a metanalysis of at least 100 quality studies.
We need to rethink this…