We had our difficult child 3 on a low allergy diet for some months back in 2004. Years earlier we did something similar for difficult child 1, but with no benefit. Same eventually with difficult child 3, but it's not the fault of the diet.
We went through the Allergy Clinic at Royal Prince Alfred Hospital in Sydney. Also known as RPAH. A bit far for you, but their Allergy Clinic is world-famous and does good work. They were actually doing a research project on special diet in autism. They told us that the diet issues were only found in some kids with autism, but a statistically significant number nevertheless. They gave us a booklet which had long lists of foods to give him foods to avoid and even brand names (which wouldn't help you, because manufacturers change specs form country to country).
I've done a bit of digging and found a website, for a start.
http://www.healthyfoodguide.com.au/index.php?option=com_content&task=view&id=65&Itemid=50
There are other links on that site to other groups and other sites which may be a help.
I also found a link to ASPECT, the Aussie autism society, and some discussion on the topic. It's a forum like this one, but this thread has some other web addresses posted which could be worth a look for info for you.
But for more info, search using combinations of "allergy clinic" and the hospital name, either abbreviated or in full. The head dietician there is Ann Swain - she's also written a couple of recipe books which may or may not be available. If you Google her name you might find some articles or papers.
And yes, it's all in English!
Marg
