I’m from Eastern Europe but my doctor recommended me vitamin D via fish oil as child in early nineties. So I don’t think vitamin D supplement recommendations ar

I’m from Eastern Europe but my doctor recommended me vitamin D via fish oil as child in early nineties. So I don’t think vitamin D supplement recommendations are a novelty. I think they go back decades at least in former eastern block countries. Therefor I think there must be studies showing benefit from at least 70s or 80s of not before that otherwise doctors would not be recommending it in early nineties.