The issue I've found with these discussions is it appears there's mixed evidence on if vitamin D *supplementation* actually has a positive impact, regardless of vitamin D deficiency. In other words, is the deficiency causal or correlative.
I have no opinion on the matter, and am inclined to think there is at least some positive benefit. But YMMV
I have no opinion on the matter, and am inclined to think there is at least some positive benefit. But YMMV