Doctors may be making those recommendations based on blood tests indicating specific patient deficiencies. As you note, though, research does at least suggest d

Doctors may be making those recommendations based on blood tests indicating specific patient deficiencies. As you note, though, research does at least suggest daily vitamin D supplementation in the thousands of IUs per day range may be considered safe. I'm not a doctor, but I believe if you've been directed by one to supplement vitamin D, blood tests probably should have preceded that recommendation.