Parents have long observed that some kids go bonkers after eating foods with a lot of artificial ingredients or neon-bright colors. Medical researchers--not to mention the food industry -- have been skeptical; there was no proof of this effect, at least nothing like a double-blind, controlled study.

As so often happens, however, the parents turned out to be a step ahead of the pros. A carefully designed study published in the British journal the Lancet shows that a variety of common food dyes and the preservative sodium benzoate -- an ingredient in many soft drinks, fruit juices and salad dressings -- do cause some kids to become measurably more hyperactive and distractible.