The jury's still out on the evidence, but a number of parents and doctors are convinced that diet makes a difference.
Gluten-Free Diet and Autism
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The role of diet in the treatment of autism–specifically a gluten-free, casein-free diet–is getting a lot of attention in the autism community. A growing number of parents, doctors and researchers claim that children have shown mild to dramatic improvements in speech and/or behavior after being put on a gluten-free, casein-free (GFCF) diet. However, there are no definitive studies, and this treatment has not gained widespread acceptance in the U.S. medical community.

Why Gluten- and Casein-Free
The predominant feature of a gluten-free diet (also helpful in managing celiac disease) is the elimination all wheat products and other gluten-containing foods. Gluten is the protein part of wheat, barley, and rye and is also found in food starches, semolina, couscous, malt, some vinegars, soy sauce, flavorings, artificial colors and hydrolyzed vegetable proteins.

Casein is a protein found in milk and products containing milk. Foods such as cheese, butter, yogurt, ice cream, whey and even some brands of margarine are eliminated in a casein-free diet. Casein is also often added to non-milk products such as soy cheese and hot dogs in the form of caseinate.

Changing Behavior Through Diet
The theory is that some children with autism may not be able to properly digest gluten and casein. When these proteins aren't properly digested, they form substances that act like opiates in the body. According to the theory, these substances alter the child's behavior, perceptions, and responses to the environment. Researchers in the U.S. and Europe have found substances with opiate activity in the urine of a significant number of children with autism.

If you're interested in a GFCF regimen, consult with a doctor and a dietitian before making any dietary changes. Some advocates of dietary intervention suggest removing one food from the diet at a time to determine which food may be causing a problem. It can take a while for the body to rid itself of all casein and gluten, so a three- to six-month trial is recommended to see if this diet can make a difference. Also, you must carefully read ingredient lists on food packages to look for "hidden" casein and gluten in ingredients such as curds, caseinate, lactose, bran, spices and certain types of vinegar.