
just my experience but I think it depends on the dog.
With 3 previous dogs we had, 2 had no problems but the third reacted by going hyper.......ever tried flying an 8 st Rott like a kite :-D .
We did LOTS of trial & error stuff and she reacted to any EC additives and colourings in food. similar effect to some kids and yellow colouring in drinks etc.
Chris