Food additives conclusively linked to hyperactivity

A study by researchers in the UK has shown evidence of increased levels of hyperactivity in young children consuming mixtures of some artificial food colours and preservatives, particularly sodium benzoate.

The possibility of food colours and preservatives affecting children's behaviour has long been an unresolved question for parents. This research by a team from the University of Southampton's Schools of Psychology and Medicine found that significant changes in behaviour can be detected in three-year-old and eight-year-old children.

The research, funded by a £0.75m grant from the Food Standards Agency and published in The Lancet online this month, involved studying levels of hyperactivity in 153 three-year-olds and 144 eight-year-olds living in the city of Southampton.

The children were selected from the general population to represent the full range of behaviour, from normal through to hyperactive, and not for any previous behavioural problems or known sensitivities to particular foods.

The children's families were asked to put them on a diet free from the additives used in the study. Over a six-week period the children were then given a drink each day which either contained one of two mixtures of food colours and benzoate preservative, or just fruit juice — with all the drinks looking and tasting identical.

Hyperactivity is a behaviour indicated by increased movement, impulsivity and inattention. The results of the Southampton study show that when the children were given the drinks containing the test mixtures, in some cases their behaviour was significantly more hyperactive.

The results replicate and extend previous FSA-funded research by the team in Southampton.

A combination of reports on the children's behaviour was obtained from teachers and parents, together with recordings made by an observer of the children's behaviour in the classroom and, for the older children, a computer-based test of attention. None of the participants — teachers, parents, the observer or the children — knew which drink each child was taking at any one time.

"We now have clear evidence that mixtures of certain food colours and benzoate preservative can adversely influence the behaviour of children," said research leader and professor of psychology, Jim Stevenson.

"There is some previous evidence that some children with behavioural disorders could benefit from the removal of certain food colours from their diet. We have now shown that for a large group of children in the general population, consumption of certain mixtures of artificial food colours and benzoate preservative can influence their hyperactive behaviour.

"However parents should not think that simply taking these additives out of food will prevent all hyperactive disorders. We know that many other influences are at work but this at least is one a child can avoid."