Food additives again implicated in childhood hyperactivity

A large-scale study of three-year-old children offers new evidence that common food additives can cause hyperactive behavior.

John Warner and colleagues assessed nearly two thousand preschoolers for symptoms of ADHD (attention deficit hyperactivity disorder), and for signs of allergy. The researchers then divided 277 of the children into four groups: those with both allergies and hyperactivity, those with neither condition, those with only hyperactivity, and those with only allergies.

Warner et al. then placed all of the children on a diet free of artificial additives. During the next three weeks, the children were randomly assigned to receive a placebo or a daily drink containing colorings and preservatives, with each child participating in both an additive challenge and a placebo phase. The children's behavior was rated through parent questionnaires and clinical observation, with neither parents nor clinicians knowing which children were receiving the additive-laced drinks at each stage.

The researchers report, "The observed effect of food additives and colorings on hyperactivity in this community sample is substantial, at least for parent ratings." In fact, they note, the effect of the additive-free diet on parent ratings of hyperactivity was "similar to that for [the drug] clonidine in the treatment of children with ADHD" as measured by other studies. Clinicians did not report significant changes, but the researchers say that the parents observed the children over a longer period of time and saw their reactions in a variety of settings, giving them "a greater opportunity to observe the child's hyperactive behavior."

The amounts of additives given to the children were "on the low side of normal," Warner says, noting also that exposure to the additives caused increased behavior problems in allergy- free and ADHD-free children as well as the other groups. "We were surprised by the results," he says, "because the effect was not just in one group. We showed there was an effect on perfectly normal children. If that is confirmed by further research then there is a public health issue."

The findings are similar to those of Katherine and Kenneth Rowe (see related article, Crime Times, 1995, Vol. 1, No. 3, Page 5), who found that a significant number of hyperactive children reacted very negatively to tartrazine, one of the food colorings investigated by Wagner's group. The new research also supports earlier findings by Bonnie Kaplan et al. (see related article, Crime Times, 1995, Vol. 1, No. 3, Page 5), whose placebo-controlled cross-over study found that hyperactive children placed on diets free of additives, artificial colors and flavors, chocolate, MSG, preservatives, and caffeine had significantly fewer behavior problems, slept through the night more often, and had significantly less trouble falling asleep.

"The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children," B. Bateman, J. O. Warner, E. Hutchinson, T. Dean, P. Rowlandson, C. Gant, J. Grundy, C. Fitzgerald, and J. Stevenson, Archives of Disease in Childhood, Vol. 89, June 2004, 506-11. Address: John Warner, University Child Health, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK, jow@soton.ac.uk.

"Artificial colorings and preservatives in food and drink boost levels of hyperactivity in pre-school children," The Independent (UK), May 25, 2004.