M.B.
Hi T.,
Both my boys (and I) are on the gluten free/casein free diet. This website has lots of great info:
http://www.gfcfdiet.com/
We're on the diet because we were diagnosed with celiac disease and a dairy allergy. The diet has also improved my son's behavior. My older son had some Asperger's symptoms (poor eye contact, unable to read social cues, etc.). Aspergers is on the Autism spectrum - these kids are generally very bright, just don't have good social skills. My younger son had alot of ADHD behaviors and while he's still high energy, he has calmed down alot.
You might want to ask your doctors to test your son for celiac as the gluten is known to have neurological impacts and can influence behavior (this is more recent research and not all doctors are aware). You can do the testing yourself through enterolab: www.enterolab.com
The reason why testing might be important is due to the cost and difficulty of sticking to the diet that another poster mentioned.
There is also an excellent doctor in the DFW area that is a member of the DAN organization: Dr. M. Ann Block www.blockcenter.com I had considered taking my boys to her (and I did attend a seminar she held at her office) if I hadn't gotten such positive results from the dietary change and adding some of the supplements she recommends (e.g., B vitamins, magnesium, etc.)
You are a great mom to be considering the influence of diet on your child's behavior!