Uncalled for. GP is pointing out that the fact the human body can produce Vitamin D means it is not a vitamin. vi·ta·min /ˈvīdəmən/ noun any of a group of orga

Uncalled for. GP is pointing out that the fact the human body can produce Vitamin D means it is not a vitamin. vi·ta·min /ˈvīdəmən/ noun any of a group of organic compounds which are essential for normal growth and nutrition and are required in small quantities in the diet because they cannot be synthesized by the body.