Gluten Free Diet & Autism

Once again I was browsing the web tonight looking at the news on autism and I stumbled upon an article that talked about Gluten Free and Casein Diets. The article says the current research says that this does not improve autism. Here's the article: LINK Well, I am sitting here scratching my head as if they don’t know what causes it how the heck do they know if it improves it or not. Another point was that these diets could cause nutritional deficiencies in kids. Now I don’t do any special diets with Dakota as I have thought about it. I suppose that is where the DAN doctor topic comes in. Maybe not… Anyways for anyone that does follow this diet with their child does it just seem to help with behaviors or is there more that I am missing. I know I have heard people say this diet has been very good. I just would like to hear what others thoughts are on this. If they have experience with this… what has improved?