Hi there,
It might be worth having a look at Sue Dengate's website - if you google 'fed up with food additives' you should be able to find it. My DD2 often presents me with challenging behaviours to deal with, and i can usually blame it on the food she has eaten. Even foods which we think are healthy and nutritious, like fruit and vegies, can affect behaviour. Her behaviour may not be related to this, but it's interesting reading anyway. Worth a try if it helps in any way . Good luck