I've read a book by Dr. Russell Blaylock on anti-oxidants and how important they are for you and a whole lot of other things that where surprising...it was an interesting book..
http://www.blaylockreport.com/
If you want to check out vitamins to see if they contain contaminants or if they actually dissolve in your system there's a web site called Consumers Lab that tests these things...the site has a fee, I think there's a fee for 30 days and a fee for a year....
http://www.consumerlab.com/