Artificial food colourings and preservatives have a “significant” impact on hyperactivity levels in very young children, say researchers, and removal of these substances could be in the long-term interest of public health. The authors base their findings on over 1,800 three-year-old children, who were screened for hyperactivity and allergies.

Almost 300 children, divided into four groups, completed the four-week study. During the first week, the children ate only foods free of artificial additives, including colourings, such as tartrazine, sunset yellow, and carmoisine, and the preservative sodium benzoate. During the second and fourth weeks they were randomly assigned to a daily dose of fruit juice, with or without colourings and preservatives.

The children’s behaviour was assessed before the study began and regularly throughout the study period by formal clinical assessment and parental diaries. The parents were unaware which type of juice had been given to their child.

Parental ratings showed that the children became significantly less hyperactive during the period when the additives were removed from the diet, and much more hyperactive when they were put back in. The authors suggest that for those children with high hyperactivity scores, this translates as a reduction in prevalence from 15% to 6%. While these changes were not reflected in the formal clinic assessments, the authors suggest that parental ratings might be more sensitive, as parents see their children’s behaviour over a longer period of time, in more varied settings, and in less optimal conditions.

British Medical Journal, May 21, 2004