Just wanted go to give an update: our son (now four years old) is doing very well and has improved drastically in his stuttering since going gluten/grain/dairy/sugar/soy free. He had been stuttering (what I would classify as the moderate/severe range) for well over a year, and it has been four months since we changed his diet. I would say it took about 6-8 weeks to really see a difference, but then it was very noticable that he had improved, it was almost magical and unbelievable. We had a period of several weeks in there where he had NO stuttering at all. Then I'm not sure if we got some trace gluten contamination somehow or if he is still going through his speech “cycles”, but he is now recovering from a very mild set-back. Four months ago on a scale from 1-10 he was stuttering anywhere from a 6-10 depending on the day. Now, he goes from 0-1 most of the time, to 2-3 at the worst. Due to this, I am considering adding some other supplements such as omegas, vit D, magnesium at some point, but right now he only takes a multivitamin.
It has been such a relief as a parent and we can see he is much more relaxed and social. He has even improved behaviorly and seems to run and jump better than before (but of course that could also just be his age). I would definately recommend anyone with a child that stutters to at least give it a try.
This is the link from Dogtor J that got me going onto this subject: http://dogtorj.com/?page_id=434 I haven't contacted Dr. Symes yet, but I would like to personally thank him. The speech pathologist we went to told us that (even with our family history of celiac and food intolerances) food or diet probably had nothing to do with his stuttering.