Effects of artificial food colorings in children with hyperactive symptoms. A critical review and results of a controlled study
The "Feingold diet," which eliminates artificial food colorings, has been claimed to be beneficial to hyperactive children. Previous studies have yielded equivocal results. We sought to maximize the likelihood of demonstrating behavioral effects of artificial food colorings by
(1) studying only children who were already on the Feingold diet and who were reported by their parents to respond markedly to artificial food colorings,
(2) attempting to exclude placebo responders, and
(3) administering high dosages of coloring.
The design was a double-blind crossover with randomized; 11 children maintained on the Feingold diet were challenged with food coloring and placebo (one each week). Evaluations by parents, teachers, and psychiatrists and psychological testing yielded no evidence of a food coloring effect.
FAB RESEARCH COMMENT:These researchers are to be commended for using a randomised, double-blind, crossover design for this study. It is also commendable that they studied only children previously reported by their parents to show adverse reactions to artificial food colourings (AFC) - as a failure to do this would not provide an adequate test of the hypothesis that some children react badly to such additives. Despite this, the results of this trial provided no evidence of adverse effects of AFC on these children's behaviour.
Obviously the study numbers here were very small, making it extremely difficult for any differences between the intervention and placebo conditions to reach conventional levels of 'statistical significance' unless these really were huge. However, given the lack of any observable effects - according to either parent and teacher ratings or psychological assessments - it seems safe to conclude that the improvements in their children's behaviour previously reported by these parents following adoption of the 'Feingold diet' are unlikely to have resulted from the exclusion of AFCs themselves.
As the Feingold diet involves major changes to many other aspects of the diet, it is quite possible that any of these might have an influence on children's behaviour. Equally, numerous other factors - including parental expectations, and/or children's responses to the attention being paid to their diet and/or behaviour, might help to explain any genuine behavioural changes previously observed by these parents. Further studies would be needed to distinguish between these possibilities.