Gluten

Research shows that gluten – a mixture of proteins found in grains such as wheat, barley, and rye – can increase systemic inflammation when ingested. Gluten seems to particularly negatively affect the functioning of a part of the brain called cerebellum. People with autism often have decreased functioning of their cerebellum. Consuming gluten can just make it much worse.
Although the research on gluten-free diets does not give clear results, many parents of children with autism report seeing improvements in symptoms when they eliminate gluten from their child’s meals.