Common Food Additive Doubles Kids' Hyperactivity
Sodium benzoate seems to be much more than just a preservative...
by Richard Hollingham
Can food additives affect children’s behavior? A study published in the November 3 issue of the British medical journal The Lancet suggests they can.
A team from the University of Southampton in England measured levels of hyperactivity in 153 three-year-olds and 144 eight- and nine-year-olds. The children were put on a diet free of the additives used in the experiment. Then each day over a six-week period they were given one of two mixtures with artificial coloring and the preservative sodium benzoate, or a plain fruit juice placebo. All the drinks looked and tasted identical.
Researchers observed the children in the classroom and analyzed reports of their behavior from parents and teachers. The older kids were also given a computer-based attention test. The results from all these tests were scored to produce a measure of hyperactivity known as a global hyperactivity aggregate (GHA). The higher the GHA, the greater the hyperactivity.
On average, the children who drank the additive concoctions showed a near doubling of GHA scores compared to those on the placebo. This was true for the younger and older children. Investigators also reported differences in the way individual children responded to the additives, with some becoming much more hyperactive than others.
“The study shows that, on average, children have higher levels of hyperactivity when taking a drink with additives in it compared to their behavior when taking fruit juices alone,” says Jim Stevenson, head of the study.
Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial
We undertook a randomised, double-blinded, placebo-controlled, crossover trial to test whether intake of artificial food colour and additives (AFCA) affected childhood behaviour.Methods
153 3-year-old and 144 8/9-year-old children were included in the study. The challenge drink contained sodium benzoate and one of two AFCA mixes (A or B) or a placebo mix. The main outcome measure was a global hyperactivity aggregate (GHA), based on aggregated z-scores of observed behaviours and ratings by teachers and parents, plus, for 8/9-year-old children, a computerised test of attention. This clinical trial is registered with Current Controlled Trials (registration number ISRCTN74481308). Analysis was per protocol.Findings
16 3-year-old children and 14 8/9-year-old children did not complete the study, for reasons unrelated to childhood behaviour. Mix A had a significantly adverse effect compared with placebo in GHA for all 3-year-old children (effect size 0·20 [95% CI 0·01–0·39], p=0·044) but not mix B versus placebo. This result persisted when analysis was restricted to 3-year-old children who consumed more than 85% of juice and had no missing data (0·32 [0·05–0·60], p=0·02). 8/9-year-old children showed a significantly adverse effect when given mix A (0·12 [0·02–0·23], p=0·023) or mix B (0·17 [0·07–0·28], p=0·001) when analysis was restricted to those children consuming at least 85% of drinks with no missing data.Interpretation
Artificial colours or a sodium benzoate preservative (or both) in the diet result in increased hyperactivity in 3-year-old and 8/9-year-old children in the general population.