Two hundred seventy-seven children (aged 3 years) living on the Isle of Wight, UK, consumed a diet for four weeks that eliminated artificial colorings and benzoate preservatives. During the second week of the diet, the children were randomly assigned to receive, in double-blind fashion, daily challenges with a drink containing either 1) artificial colorings (20 mg/day total; 5 mg/day each of sunset yellow, tartrazine, carmoisine, and ponceau 4R) and sodium benzoate (45 mg/day) or 2) placebo. During the fourth week, the children were challenged daily with the alternate drink.
During the first week (the elimination phase), a significant reduction in hyperactive behavior was observed. In the challenge phase, significantly greater increases in hyperactive behavior were seen with the food additives than with the placebo. These differences were identified by parents’ ratings but not by objective testing in the clinic. The magnitude of the benefit obtained by avoiding food additives was similar to that for clonidine in the treatment of children with ADHD, but was less than that seen with methylphenidate (Ritalin). The effect of the food additives on hyperactive behavior was not influenced by the presence or absence of hyperactivity at baseline, nor by the presence or absence of atopy, as determined by skin prick tests.
Comment: There have been many studies assessing the effects of food additives. While many of these studies demonstrated an adverse effect of food additives, others found little or no effect. Some of the negative studies suffered from design flaws. For example, one study compared the effect of a chocolate cookie containing artificial food dyes to that of a "placebo" chocolate cookie. Some children in that study may have experienced an adverse reaction to the chocolate "placebo", which would have masked any effect of the food dyes. In other studies, children underwent challenges with food dyes after they had been on an additive-free diet for at least three months. Tolerance to allergens tends to increase the longer a person avoids them, so the children in those studies may have lost their sensitivity to the additives by the time they were challenged with them. Moreover, most of the previous studies investigated only artificial colors, not sodium benzoate, which appears to be an important symptom-evoking substance.
The present study demonstrates that commonly used food additives contribute to hyperactive behavior in children, and that the effect of these additives is not influenced by prior levels of hyperactivity or by atopy. An earlier study (Lancet 1985;1:540-545) also showed that food dyes and benzoate preservatives are frequent triggers of hyperactive behavior; in that study, however, common foods such as dairy products, chocolate, grapes, wheat, oranges, and eggs also played a significant role.
Considering that more than 1 in 20 children in some areas of the country is on Ritalin or other drugs for hyperactivity, closer attention should be given to the dietary factors that are causing problems for these children.
Bateman B, et al. 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. Arch Dis Child 2004;89:506-511.
