Way way back in my 20's, I got my college diploma in early childhood education, and worked many years as a live-in nanny and in daycare. Even back then there was clearly a link between diet and behaviour, and more than enough evidence that food dyes had a detrimental impact on young children. IMHO many children who have been diagnosed with ADD may well have an oversensitivity to additives and food dyes (in particular the reds). We've seen this in our own grandson, whose behaviour changed dramatically when his parents cut out everything with red dye (including cough syrups).

While on my course, I did two of my required essays and projects on autism, involving a lot of reading and research. I remember reading that limiting chemical intake and sensory overstimulation helped minimize the children's stress (and subsequent behavioral reaction to the stress).

I think one of the best experts in the field is Dr. Temple Grandin, an autistic woman whose insights into autism are amazing (http://en.wikipedia.org/wiki/Temple_Grandin) - I found the movie about her very inspiring.