Earth Citizen, on 20 April 2012 - 11:45 PM, said:
High doses equals harmful eh?
That would certainly explain why the evidence is so divided on them. So the healthiness of vitamin consumption is an n-curve?
That's actually true for anything that you put in your body. The usual description of the healthiness curve is an "inverted U". The only question, and it's a pretty big one, is what exactly is the dose that corresponds to maximum health, as well as the degree to which the curve is sloped.
Another problem with multis involves the form of the vitamin or mineral. Folic acid, for example, has a polyglutamate chain as we get it from nature, but the synthetic forms leave that off. Cheaper multis tend to have poorer forms, while high-end multis like Vimmortal, Ortho Core or AOR Multi Basics have better forms.
I'm not so sure that the evidence on multis is all that divided. There have been some large observational studies showing positive results with long term use of multis. Offhand, I can't think of any obvious "multis are bad" studies.