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

McCann D, Barrett A, Cooper A, Crumpler D, Dalen L, Grimshaw K, Kitchin E, Lok K, Porteous L, Prince E, Sonuga-Barke E, Warner J O, Stevenson J (2007) The Lancet 370(9598) 1560-7

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Abstract:

A randomised, double-blinded, placebo-controlled, crossover trial was undertaken 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 [0.2-0.23], 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.

FAB RESEARCH COMMENT:

Once again, a rigorously conducted randomised, double-blind, placebo-controlled trial has shown that certain common food additives have detrimental effects on children's behaviour - increasing hyperactivity in both 3-year olds and 8-9 year-old children.

These findings replicate and extend those from an earlier controlled trial by the same research group, involving pre-school children only:

Bateman et al (2004) The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children.

The additives tested were the same combination, as previously used - i.e. several artificial food colourings, and sodium benzoate (a preservative commonly used in soft drinks and other foods often consumed by children).

This group of additives has now been labelled by the media as 'The Southampton Six' (after the University where the leading researchers are based).

Importantly, like the previous Southampton trial - this study involved children from the general population - not just those with obvious pre-existing behaviour problems such as hyperactivity or ADHD.

Earlier controlled trials investigating this issue have already shown that artificial food colourings - particularly the 'azo dyes' derived from petroleum products (including tartrazine or 'Sunset Yellow') can worsen the behaviour of children with hyperactivity / ADHD or related behavious problems.