I don’t think that’s really the blocker here. Vitamin D supplementation is very low risk and the risks are well known. I’ve seen at least one study that I can recall saying exactly that—the correlation is there and vitamin D is safe and basically risk free so we should be supplementing it in at least the at-risk population immediately.
Not particularly. They tend to have faulty liver more often though preventing them from producing enough cholesterol, and need more to handle the general cell damage, so less remains in the skin to synthesize vitamin D...
