Diet affects many of our cognitive and neurological functions. Things we eat target specific neurotransmitters and hormones thereby contributing to manufacturing of our physiological responses. Some thing casein free gluten free diets reverse autism spectrum disorders. Let us view this logically.
Casein, being dairy, has several known side effects, such as bloating, pain, gas, gastroesophageal reflux, and allergy and cold symptoms. That alone can make one miserable. Gluten can cause bloating, headaches, depression, fatigue, anxiety, abdominal pain, autoimmune disorders, brain fog, and more. Some of these symptoms overlap conditions that fall on the spectrum. Removing casein and gluten alleviates their contributions to other disorders that affect autists. It is not a cure for autism. It is a way of reducing symptoms by eliminating triggers that exacerbate other disorders experienced by those on the spectrum.
People argue that their children stopped being autistic when their diets changed. That is similar to saying someone’s skin color changed from dark brown to paper white by altering his/her diet. Or your eye color changed when you drank milk.
Diet is important, but it does not alter genetics.