Can gluten and casein free diets help reverse behavior in autistic children?

In the last decade, there have been suggestions that perhaps diet may play a role in the cause of autism. Throughout the years, hundreds of different diets have been developed to either prevent or treat autism; - in every single case, these diets have had no impact on the disease. Now another diet has been added to the list- gluten and casein free diets.

Many women with autistic children have been buying these expensive diets in the hope of reversing symptoms of autism. There are many anecdotal reports on benefits of gluten free diets- most are made by people who have a financial interest in the business of selling such diets.

So is there any real evidence that gluten and casein free diets help improve outcomes in autistic children?   A few studies have shown that gluten and casein free diets have no impact on autism - the only impact is in the pocket as these diets are exorbitantly expensive.

While the few studies show no benefit of gluten free diets in autistic children, no one has bothered to show if long-term use of these diets is safe in these children!