In children with autism, there is already extensive disruption of biochemistry, so blindly adding supplements on a prospective basis can exacerbate the illness. Specific metals which are in deficiency should be replaced, but the use of complex mixtures of metals can often be self defeating. For example, Zinc mixed with Copper and Iron gives a competitive mixture for absorption in the gut. The actual absorption of any one of these will be at best erratic, and result in wastage due to non absorption. Many high street preparations contain this mixture.
Dietary management is very important for children in general, and autistic children in particular.
However, dietary faddism by the child, because of behavioural choice, or diets applied such as gluten free, casein free and others, can lead to malnutrition. It is not uncommon in my clinic to see children who have fallen away on growth charts, and even some with severe malnutrition. Phenol sulphyl transferase is an enzyme which is non specific in its activity. It appears to be affected by food colourants, which have a preferential binding to the enzyme, thus preventing breakdown of adrenaline and like stimulants. Other substances include food with a high amount of phenolic groups.