Food additivesArtificial food colourings and preservatives have a "significant" impact on hyperactivity levels in very young children, according to new research from the UK.
Removal of these substances from food and beverages could be in the long-term interest of public health and, in particular, could provide health benefits for children, according to the research team.
While noting the study, the Food Safety Authority of Ireland (FSAI) stressed that there was "no conclusive evidence" that approved additives could cause hyperactivity in children. There remained, however, a degree of "parental responsibility" to ensure children did not consume too much of the processed foods that contained these additives.
The study looked at the effect of commonly used food colourings and preservatives on the hyperactivity levels of three-year-olds. Carried out by the Department of Child Health at the University of Southampton, the results were published in the current issue of Archives of Disease in Childhood.
The authors screened more than 1,800 children, looking to exclude pre-existing hyperactivity and known allergies. Almost 400 children were selected and about 300 actually completed the four-week double blind, placebo-controlled trial.
During the first week, the children ate foods free of additives including benzoate preservative, and tartrazine, sunset yellow and carmoisine colourings. After this, groups were randomly selected and given a dose of fruit juice with or without colourings and preservatives.
The children were assessed in two ways, both by formal clinical assessment for hyperactivity and also through parental diaries. The parents didn't know which type of juice their child was given, but were asked to report on behaviour.
Parental ratings later showed that the children were significantly less hyperactive when the additives were missing from the diet and much more hyperactive when they were included. Conversely, there were "no significant differences detected based on objective testing in the clinic", the authors report.
The researchers commented on failure of the clinical tests to detect changes in hyperactivity, proposing they were not sensitive enough to pick up the behaviour changes seen by parents.
"Parental ratings might be more sensitive to changes in behaviour in that parents experience their child's behaviour over a longer period of time, in more varied settings and under less optimal conditions," the authors say.
The parental scores indicated that hyperactive behaviour doubled while the children were receiving additives. The authors calculate that absence of additives in the diet reduced the prevalence of hyperactivity from 15 per cent to 6 per cent in the subjects tested.
"These findings therefore suggest that significant changes in children's hyperactivity behaviour could be produced by the removal of artificial colourings and sodium benzoate from their diet," they conclude.
They also argue that public health gains would follow if these additives were removed from the diet. "The potential long-term public health benefit that might arise is indicated by the follow-up studies which have shown that the young hyperactive child is at risk of continuing behavioural difficulties, including the transition to conduct disorder and educational difficulties," they say.
"We believe that this suggests that benefit would accrue for all children if artificial food colours and benzoate preservatives were removed from their diet."
They urged further research, calling for similar studies on a broader age range including older children and young adults.
The question of hyperactivity and food additives remained an area of "scientific uncertainty", the acting chief executive of the FSAI, Alan Reilly, stated yesterday. No comprehensive study had yet shown this link, he said.
"With respect to the additives, there is no conclusive evidence the additives are going to cause hyperactivity in children," he said. All additives went through batteries of tests, but dosage was an issue. "In low doses you are not going to have any effect," Mr Reilly said. "If a child is drinking a litre or two of fizzy drink, you can get into an area where they are over-consuming."
There was also the effect caused by the high sugar content of many of these foods, he added. It was down to "parental responsibility" to ensure a child ate a balanced diet.
