i'm not a real smart guy, so what works best for me when i'm trying to solve a problem, is to eliminate all the stuff that might get in the way - can't really give you an example other than when i'm working on figuring out what foods are giving me fits, i get rid of EVERYTHING that i'm currently doing that isn't an absolute necessity - you know, like water or ..........
i have gone hungry a lot and i know that would be difficult for your son, so ya, things like the iron pills should probably go - and these are not permanent changes, just for a few days or weeks just to see if something jumps out - he'll live without a lot of the things you are giving him -
it's just easier for me to get rid of potential problems before i start trying to add things to the equation -
definitely agree with bloom & gary !