Grain Addiction: opioid-excess theory

I found this scientific article while I was trying to prove a point to another doctor.  He and I were discussing some common themes seen in kids with Autism Spectrum Disorders (ASD).  One theme that I had seen and heard over and over were that they were very picky eaters and would only eat wheat-products (bread, pasta, cereal, etc..) and dairy.  I heard from various sources that the proteins in these foods got converted to an opioid-like substances that partially explained not only the behavior seen in these patients, but also their addiction to these very foods.  I decided to look through the scientific literature to see if there was any real evidence to back it up and found this excellent article:

Biochemical aspects in autism spectrum disorders: updating the opioid-excess theory and presenting new opportunities for biomedical intervention. Paul Shattock & Paul Whiteley. Expert Opin. Ther. Targets (2002) 6(2): (link)

When I read the introduction to the article, I knew this is what I was looking for:

Ben is three years old and until two weeks ago had never uttered a single word. Ben has autism. Following discussions with other parents, his mother decided to experiment by removing all gluten from Ben’s diet. Three days later, Ben started shouting; ‘I want bread. Give me bread.’ Was this pure coincidence? It could be, but similar coincidences have been reported tens of thousands of times worldwide.

The rest of the article discusses the diagnosis of ASD, current theories of cause, current treatments, and various “experimental” therapies that are being used and the concepts behind them.  I was most intrigued by the similarity of long-term morphine use and patients with ASD:

• reduced desire for social contact
• insistence on sameness
• decreased pain sensitivity
• delay in developmental milestones