Food additives found to fuel hyperactivity
Drink with preservative, artificial colouring had 'significantly adverse' effect, study says
Ordinary food colouring and a common preservative found in everything from fruit drinks to jam have been conclusively linked to hyperactivity in children for the first time, according to British researchers.
Their findings, published today in The Lancet medical journal, could have profound implications for the regulation of additives and the diets of children who exhibit frenetic behaviour, researchers said.
Within hours of announcing the results of the study, the Guardian newspaper reported that the British government had taken the significant step of recommending that parents avoid giving products containing multiple additives to children who show signs of hyperactivity.
The study involved 153 preschool children and 144 aged 8 or 9 who were given ordinary fruit juice or one of two drinks identical in look and taste that contained varying levels of artificial food colouring and a set amount of the common preservative sodium benzoate.
One batch with the additives contained the average daily intake of food colouring for both age groups. The other had elevated levels equivalent to two 56-gram bags of sweets for the three-year-olds and four bags for the older children.
None of the children had extreme hyperactivity or attention-deficit disorders, and they did not consume other foods containing sodium benzoate during the six-week study.
Investigators reported that the drink containing benzoate spiked with the higher level of food colouring had a "significantly adverse" effect on the three-year-olds, while both mixes increased hyperactivity in the eight- and nine-year-olds.
Across the board, the children who consumed the elevated mix moved about 10 per cent closer to an internationally accepted definition of hyperactivity.
"We now have clear evidence that mixtures of certain food colours and benzoate preservative can adversely influence the behaviour of children," said researcher Jim Stevenson, a professor of psychology at the University of Southampton.
Citing previous research that suggested that some children with behavioural disorders could benefit from removing certain food preservatives and colours from their diet, Dr. Stevenson said simply removing the additives from food would not prevent hyperactivity in children. "We know that many other influences are at work, but this at least is one a child can avoid," he said.
Links between diet and hyperactivity have been vigorously debated for more than three decades, with researchers on both sides dismissing the others' findings as inconclusive.
Experts on hyperactivity and food additives attribute the failure to arrive at any firm conclusions in part to the difficulty of isolating for study the numerous additives and preservatives commonly found in food.
Fluctuations in hyperactive behaviour among children under the microscope have also muddied past research.
So the news yesterday that researchers claimed to lay to rest any doubt that food additives contribute to hyperactivity was greeted with skepticism by the International Food Additives Council, an Atlanta-based trade association.
"It's been my impression that, when it comes to anecdotal studies, there are people who tend to think food additives have something to do with hyperactivity. But when you put these studies into more carefully controlled situations, they don't pan out," said Andrew Ebert, a consultant for the trade association, who noted that he could not comment directly on the study because he had not seen it. Dr. Ebert said the organization would review the findings in the coming days.
The theory that hyperactive children could benefit from a diet devoid of artificial colours and flavours was pioneered in the 1970s by Ben Feingold. His Feingold Cookbook for Hyperactive Children, published in 1979, proposed eliminating such things as soft drinks, cake and luncheon meat from the diets of youngsters.
While much of Dr. Feingold's work remains controversial, pediatricians who specialize in treating overactive children say it is generally accepted that some foods worsen hyperactivity in some children. They note, however, that no evidence suggests certain foods cause hyperactivity, and that behavioural reactions to food are often subtle.
Bill Mahoney, associate professor of pediatrics at McMaster University, said after reviewing the British study yesterday that its findings reinforced those notions. "This isn't taking very placid children and turning them into kids who are running all over the place," Dr. Mahoney said. "The effects, in general, are very small."
Philip Shaw, a clinical fellow at the National Institute of Mental Health in Bethesda, Md., said the study was probably the most comprehensive of its kind, but questioned whether it would have the sort of far-reaching implications that its researchers imagined.
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Sodium benzoate
What is sodium benzoate?
E211, also known as sodium benzoate, is a derivative of benzoic acid. It is added in large amounts to carbonated drinks to prevent bacterial growth.
What other health concerns are related to sodium benzoate?
Health Canada found 20 per cent of soft drinks and other beverages it analyzed in a spot check last year included benzene, a known carcinogen. Where are additives like sodium benzoate and food colouring found?
Sodium benzoate is widely used in carbonated beverages, and artificial food colouring is used in candies, ice creams, drinks and many other kinds of snacks.
What happens if children eat them occasionally anyway?
The study showed that some children appear to be more susceptible to hyperactivity than others. Kids with behavioural problems may benefit from eliminating these additives from their diets, while others are able to handle occasional exposure.
Source: The Globe and Mail and the Guardian