Even though for a number of years many parents with children who are affected by Attention Deficit Hyperactivity Disorder (ADHD) have been excluding foods which contain such ingredients from their child's diet as a precaution, the practice has until now had little scientific basis.
But now researchers from the University of Southampton in a study sponsored by the British Food Agency, have systematically established for the first time the connection between the two.
The study which was led by psychology Professor Dr. Jim Stevenson, provides clear evidence that mixtures of certain food colours and benzoate preservative can adversely influence the behaviour of children.
For the study the researchers distributed drinks for a six week period, containing preservatives and colours similar to those mixed in common commercial drinks to a group of 153 three year old children and 144 eight and nine year-olds who had been selected at random.
The children were given two types of drinks with food additives commonly found in sweets, beverages, and other foods, and then a placebo drink (one with no additives).
One mix had artificial colorings, including sunset yellow (also called E110), carmoisine (E122), tartrazine (E102), ponceau 4R (E124), and the preservative sodium benzoate.
Another 'cocktail' included the current average daily consumption of food additives by the two age ranges of children and included quinoline yellow (E104), allura red (E129), sunset yellow, carmoisine and sodium benzoate.
Teachers and parents were then asked to evaluate the children's hyperactivity and inattention with the help of a computer test without knowing which drink the child had been given.
The researchers found that the children who received the drinks containing the additives and preservatives were noticeably more hyperactive and had shorter attention spans.
The older children's behaviour was more affected by both of the mixtures with additives, compared with the placebo, while the younger children had more hyperactivity with the first mixture compared with placebo.
Stevenson says the study does not pinpoint which additives are the main culprits because all the children were given a mix of additives and rather than a particular one.
The British Food Agency advises parents to monitor their children's behaviour and should a conspicuous change occur after consuming food with additives, parents should regulate their child's diet and exclude artificial preservatives and colours.
Parents are advised to read food labels when buying products for their children and the campaign group, the Food Commission has called on food manufacturers to "clean up their act" and voluntarily remove additives from their products.
According to the National Institutes of Health as many as 2 million children in the U.S. have ADHD.
The study is published on line in the current edition of The Lancet.