> The vast majority of Americans do not have a vitamin deficiency, this has born out over and over again.. Primarily due to fortified items.
Just pointing to fortified flour and handwaving away the entire issue is no real argument. It just shows that you are happy to be ignorant. Most people are. It takes a degree of effort to be aware of these things.
You probably have no clue at all how you relate to the government recommendations. You just have blind faith that others will take care of things for you.
Now I do have some awareness of these issues. That's why I raised the question that I did. I have much less faith in the magic unicorns ensuring that everyone gets all of the vitamins the government says they should be getting.
The issues here are likely subtle enough that a study of this kind is pretty meaningless either way.
People aren't dropping like flies from Niacin deficiency. That doesn't mean there couldn't be other issues.