There's no evidence that special diets are an effective autism treatment.
Some people believe that diets that are free of a protein found in dairy products (casein) and a protein found in many grains (gluten) affect the brain development and behavior that causes autism in children. However, there's little evidence that diet triggers autism or that restricting gluten and casein improves autism symptoms. And for growing children, restrictive diets can lead to nutritional deficiencies. Research is ongoing on the effectiveness of casein- and gluten-free diets.
Autism is a complex brain disorder that has no known cure. For this reason, many frustrated parents turn to unproven alternative treatments — such as restrictive diets that eliminate gluten and casein — in an attempt to help their children.
If you're considering an alternative autism treatment, talk to your child's doctor. He or she can help you identify the treatments that are most likely to be effective for your child, as well as local resources that may provide additional support. If you decide to pursue a restrictive diet, work with a registered dietitian to create an appropriate meal plan for your child.