K.V.
My niece has had allergic reactions to Red Dye #40, where she completely avoided it for a while. The doctor did mention to my sister that sometimes children can react to that through their behavior, as well. Very interesting... Oh, and amazing to know the things that contain Red Dye #40....Crescent Rolls to name one of the oddest!! She recently began introducing it again in her diet (in small, controlled amounts) and does notice in the behavior a connection between them.
So, her experience and what she was told certainly supports what you wrote. I had never heard that until she told me.