In all of the reading I have been doing about food allergies, autoimmune disease, digestion, and ASD (autism spectrum disorder), there seems to be a common denominator: inflammation. Inflammation of the gut and brain are present in ASD. Between 6 months and 2 years, ASD kids experience fast brain growth, which gives way to unusually large heads in that time period. A five-year-old with autism has the same size brain as an average 13-year old. This inflammation leads to decreased blood flow/oxygen to certain parts of the brain.
Here is an article from the NY times that explains these abnormalities. Here is an article about neurological inflammation and autism. Here is a VERY interesting article about hyperbaric oxygen therapy used to treat the inflammation and decreased blood flow to the brain. It is also used to treat other autoimmune diseases. Lance Armstrong owns a hyperbaric oxygen chamber and uses it to enhance athletic performance.