hihi Parent J and Shelly,
im only into gluten free casein free (GFCF) diet about 9 months or so... with my boy of 5 years.. it has been tough and i cant be sure of any significant results (YET).. tough bcoz its expensive... haha and takes some time for my boy to get used to.. like no more horlicks for him (gluten also found in rye, barley,..) which he really loves.
you must be sure to read all the labels on packaging. there's alot of things that i missed out when i just started.. eg. soya sauce, pasta sauce, instant mashed potatoes, sweets, etc. must really becareful bcoz the least expected things might contain it like even some potato chips (Pringles!!) has wheat flour in the seasonings.
must also watch out for packaged products, for eg you may think rice cereals dont is gluten free but they often contain malt flavourings which is made from barley and contains gluten. so always check, double check, triple check just in case!
when you go out and eat, many hawker centre food are out. bcoz many food use sauces like soy sauce, dark soya sauce, etc. must ask if u want to buy but now i always cook and pre pack for him bcoz its easier.
for casein, its found in alot of food. milks... biscuits,.. icecream... even lollipops.. i treat him to some homemade sorbet since he cant eat the typical icecream you can find outside.
when i first started out i did alot of research bcoz i was never on this diet.. and no one i knew was on this diet either..
here's a website i found to be quite useful for food substitutes: https://www.tacanow.org/family-resources/gfcfsf-ingredients-and-substitutions/
i know it sounds tough but its only the beginning. my son is also allergic to dairy so i had to make sure he only drinks nut milk.. like rice milk. i wanted to give up many times bcoz its soso hard and also cheated many times. but i have heard of some success cases and wanted to try this out to see if itll help him. hes finally getting used to it after 3 months. if u start earlier i think itll be less difficult for ur kid to get used to the food.
all the best to your kids! :)