Additives and hyperactivity - jury still out
children may be having an adverse effect on behavioural patterns
may be right - although clinical studies failed to support their
concerns, say researchers about to embark of a secondary
investigation.
Scientists from the University of Southampton in the UK recruited 277 three-year-old children from the Isle of Wight, whose parents kept them on a diet carefully chosen to be free of the additives. In certain weeks, the children were then given a daily drink that either contained the additives and a benzoate preservative or an identical looking and tasting fruit drink. Neither the parents nor the children knew which type of drink was being given although the study design meant that they knew when they were being tested.
Reporting their findings in the June 2004 issue of the Archives of Disease in Childhood journal, the scientists said that while most parents did indeed report more disruptive and inattentive behaviours on those weeks the children received the drinks with additives (even though the parents did not know which drink was being taken), some also reported poorer behaviour by their children even when they had only been given the pure fruit drink.
Furthermore, clinical tests failed to detect any signs of hyperactivity among those children who had been given the additives, even when their parents had reported the change in behaviour.
The findings suggest that benefits may arise from removing these additives from children's diet, but the researchers stressed that a number of questions remained to be answered, not least why parents reported a noticeable effect from the drinks but clinical tests failed to show any behavioural differences.
One possibility, put forward by the scientists, is that the tests were not sufficiently reliable with children of this young age, although it could also be the case that those families completing the study may not have been representative of all families or that the effects produced by the pure fruit drink (a placebo effect) were large.
The scientists said that it was important to conduct further work to determine whether behavioural changes can be found in older children and to try to confirm the effects reported by parents by other means, for example by observing the children's behaviour at school. Reducing the level of placebo effects would also give a more accurate reflection of the effect of additives.
The UK Food Standards Agency, which funded the original study, has now awarded the research team a further contract to investigate these questions as part of the Food and Behaviour in Children (FABIC) study. This new research will also allow the investigation of children's biological reactions to food additives and how these might influence behaviour.
Professor Jim Stevenson of the University of Southampton's School of Psychology said that the further research posed a real challenge. "If we can demonstrate whether or not these food additives have a detrimental effect on children's behaviour, then this will be a significant step forward," he said.
Professor John Warner of the University's School of Medicine added that the work was the culmination of long history of research on this question. "This further study funded by the Food Standards Agency should be able to tell us more conclusively whether these food additives are affecting children's behaviour."
