Shanna Freeman of HowStuffWorks explains that the autism diet, otherwise known as the "gluten-free, casein-free" diet, is a strict elimination diet that removes all food sources of gluten and casein. It is thought that avoiding these proteins helps people with autism because the substances may create behavioral changes as a result of allergies or leaky gut syndrome. Many doctors remain unsure of the validity of these claims.
On the autism diet, patients must avoid sources of casein, caseinate, sodium caseinate, lactose and whey, explains Freeman. This applies to food items such as milk, yogurt, butter, ice cream and cheese. Some salad dressings, soups, vitamins, cookies and hot dogs must also be avoided, notes Freeman. Gluten is the second problematic protein that must be eliminated, which applies to oats, barley, soy sauce, pasta, bread, crackers and many other food items. Manufacturers also use gluten as an ingredient in items such as toothpaste, lotions and cosmetics. It is extremely prevalent and is sometimes difficult to identify in ingredient lists because it can be masked under confusing names. Since the gluten-free diet became popular for people who have leaky gut syndrome and celiac disease, it is much easier for parents of autistic children to find foods at the grocery store that do not contain gluten.