In my study on the effect of the bread preservative on children's behaviour, we asked 27 children to follow a strict elimination diet (additive free, low in salicylates, amines and flavour enhancers) before starting double blind challenges. Only two of the children failed to improve on the diet within the first ten days. When I looked closely at their diet diaries, I noticed that both were eating large quantities of a particular Arnott's biscuit so I called the manufacturer. It turned out that the biscuits contained vegetable oil with unlabelled BHA under the 5% labelling loophole. As soon as the children stopped eating these biscuits, their behaviour improved as much as the others. – Sue Dengate (Arnotts started using oil free of nasty antioxidants throughout their entire range soon after this)