It is possible that you may have overloaded her on vitamins and she is reacting to the change in diet. These type of thing usually needs to be slowly introduced.
Also kids with ADHD have a much higher percent of "accidents". And that percentage goes way up when off meds. Usually sticking to a very strict schedule is a way to help (this also helps with all phases of ADHD).
I should also add that in the years I have been the CL on the ADHD forum I have not found any info on adding a particular food to helping with ADHD. Though, I have seen some small results with Omega -3's. However, there is a lot to be said for eliminating certain foods from your diet. This can make a big difference. Check out this links for simple solutions.
http://www.medhelp.org/add-adhd/slideshows/9-Worst-Foods-for-ADD---Plus-1-That-Can-Help/20
http://www.medhelp.org/add-adhd/slideshows/8-ADHD-Culprits-Lurking-in-Your-Home/21
Finally, if you really want to try and use diet as the only way to deal with ADHD (not recommended by any professional material I have ever seen). Then what you want to try is an elimination diet. This kind of a diet will point out if food could be the cause. It is a difficult diet to administer, but this link will at least give you more information on it.
http://www.medscape.com/viewarticle/736871
And, of course if diet is not the cause, then please post over on the ADHD forum and I have lots of other resources that can help. And, by the way, her other symptoms are pretty normal for a child with ADHD - so you might want to look into what ADHD is and how it effects kids and how you can help them. Best wishes!