> Vitamins are "vital" substances that the body cannot make itself and need to be added from the outside through diet or supplementation. So if your "being the kind of person who takes vitamins" means that you eat an extremely balanced diet that covers all your macros, then you are good, but most people do not eat enough of the right foods.

But we know your first claim is not true, because the body can make Vitamin D by itself. Just because it was called "vitamin" isn't enough to mean anything.

And the second claim is just what the article is disproving!