Some common food colourings and preservatives appear to increase the risk of hyperactive behaviour among children, British researchers report.
The link between food additives and hyperactivity has long been suspected, but this is the first study to show a direct connection.
The findings have already caused the British government's Food Standards Agency, which funded the study, to issue a warning to parents about food additives.
"Attention-deficit hyperactivity disorder (ADHD) is an increasingly common problem, and theories abound to account for that," said Dr David Katz, director of the Prevention Research Centre at Yale University School of Medicine. "Among them is the notion that food additives induce hyperactivity."
More factors involved
Despite this apparent connection, Katz cautioned that the increasing number of children with ADHD cannot be blamed on food additives alone.
"No one factor is solely responsible for rising rates of ADHD," Katz said. "Along with the hazards of a highly processed food supply, children are getting less and less physical activity as a means of dissipating their native rambunctiousness."
In the study, Jim Stevenson, a professor of psychology at the University of Southampton, and his colleagues gave drinks containing additives to 297 children. The children were in two groups: 3-year-olds and 8- and 9-year-olds. The drinks contained artificial food colouring and additives such as sodium benzoate, a preservative.
These concoctions were similar to the drinks that are commercially available. The amount of additives were also similar to what is found in one or two servings of candy a day, according to the report.
As a control, some children were given drinks without additives, according to the report in the September 6 issue of The Lancet.
More hyperactive behaviour
Over the six weeks of the trial, Stevenson's team found that children in both age groups who drank the drinks containing additives displayed significantly more hyperactive behaviour. These children also had shorter attention spans. However, which specific additives caused specific behavioural problems is not known, the researchers said.
One of the additives, sodium benzoate, has been linked to cell damage in a previous study, and to an increased for cancer. Sodium benzoate is found in Coca-Cola, Pepsi Max and Diet Pepsi, and in many fruit drinks.
Other additives assessed in the study include a number of colourings - sunset yellow (E110), found in fruity drinks; carmoisine (E122), a red colouring often added to jams; ponceau 4R (E124), a red food colouring; tartrazine (E102), found in lollipops and carbonated drinks; quinoline yellow (E104), a food colouring; and allura red AC (E129), and orange-red food dye.
"Although the use of artificial colouring in food manufacture might seem to be superfluous, the same cannot be said for sodium benzoate, which has an important preservative function. The implications of these results for the regulation of food additive use could be substantial," the researchers conclude.
Based on these findings, the British government's Food Standards Agency cautioned parents to be on the lookout for hyperactive behaviour linked to food additives.
"Parents of children showing signs of hyperactivity are being advised that cutting out certain artificial food colours from their diets might have some beneficial effects on their behaviour," the agency said on its Web site.
"However, we need to remember that there are many factors associated with hyperactive behaviour in children. These are thought to include genetic factors, being born prematurely, or environment and upbringing," Dr, Andrew Wadge, chief scientist at the Food Standards Agency, said in a statement.
Insights about the causes of ADHD should help parents implement preventive strategies which are urgently needed, Katz noted. "A healthful, unadulterated diet and regular physical activity seem like a good place to start," he added. – (HealthDayNews)
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