Remove basic toxins
Having your child eat gluten-free/casein-free/soy-free (GFCFSF) is the first step in changing and improving your child’s diet. Going organic is another important steps toward better eating, improved digestion, and good health and it's the easiest way to avoid toxins.
The most common, and easy to avoid (because they have to be listed on food labels!), food toxins are Monosodium glutamate (MSG), Nitrates/nitrites, aspartame (artificial sweeteners), HFCS (High Fructose Corn Syrup) and fluoride.
Arsenic is a little harder because it's not labeled, and it's found in most poultry, rice and apple juice so make sure to do your research to find brands without arsenic, because arsenic is toxic.