The Guardian newspaper had a big splash on yesterday’s front page “New fears over additives in children’s food“. It claimed that colorings and preservatives effected children’s behaviour, possibly causing hyperactivity. Is there any science behind this latest “food is dangerous” story or is it just the latest in a long line of spacing filling, bad reporting of bad science?
ADHD and Diet
The first proponent that additives are dangerous and cause ADHD was Dr Feingold in the in the 1970’s. Backed by research he claimed that diet and adhd were linked and that if you cut out all colorings, hyperactivity went away. Later research found that the Feingold diet only helped 2% of children. However diet does seem play some part as it effects weight (see ADHD and Obesity) and diet can effect sleep patterns (see ADHD and Sleep Disorders). The current wisdom is that food additives are not dangerous but a bad diet full of fast food, sweets, fat and sugar, is dangerous and can amplify existing behavioral problems.
New Research on Additives and ADHD
The new research is a follow up to research from 2000 but only published in 2004. Researchers from the Isle of Wight in the UK looked at 277 three year old children who had been assessed for hyperactivity and atopy. The children’s diet was then changed so that for one week the children went without additives, then in random order, a week with added colorings, a week with added preservatives (sodium benzoate) and a week with a placebo. The children were assessed both by a research in a clinical setting and by their parents at home. Neither the researcher or the parents knew which order the children were receiving the additives, colorings or placebo.
When the results were analysed there were no detectable difference in the children’s behaviour when assessed by the researcher in the clinical setting. However the parent’s assessment found a significant reduction in hyperactivity in the week without additives and preservative plus an increase in hyperactivity in the week with the added preservatives.
The fact that this difference in behaviour was only notice by the parent’s is a warning sign that something might be problematic with the research. It might be that the criteria or the method of assessment being used was somehow biased or that it wasn’t sensitive enough to pick up behavioral changes in the clinical setting. It may be that parents are better judges of their own children’s behaviour or it could be that there was not difference and this is just a statistical anomaly. Without further research there was no way of telling.
Chemicals in Food
The UK’s Food Standards Agency Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) looked at this research. They conclued:
Published data suggest exclusion of specific dietary components can affect some measures of behaviour in some children. The researchers suggest that this study provides evidence that food additives had statistically significant effects on some measures of behaviour, irrespective of whether the children were atopic, hyperactive or neither. We acknowledge that the study is consistent with published reports of behavioural changes occurring in some children following consumption of particular food additives. We also note that the authors suggest that this may apply to children who are not considered to be hyperactive. However, we consider that it is not possible to reach firm conclusions about the clinical significance of the observed effects.
New research was funded to clarify the findings further and it was this new study that the Guardian was reporting on.
Are Food Additives Dangerous?
As with all good food scare stories in the media, the actual results of the study have not been published so facts cannot be checked. After the last study it took 4 years for the results to be published so don’t hold your breath. However the COT assessed the results on the 20th March and according to a member of the committee, quoted in the Guardian, the new results were the same the previous study.
Until the research is published and can be properly peer-reviewed it is impossible to say how safe or dangerous these food additives are. Until we do know, minimising children’s exposure to these additives though a healthy, balanced diet involving lots of fresh vegetables and fruit is the best advice available.
The Additives in Question
- Tartrazine (E102)
- Ponceau 4R (E124)
- Sunset Yellow (E110)
- Carmoisine (E122)
- Quinoline yellow (E104)
- Allura Red AC (E129)
- Sodium Benzoate (E211)
Original Research: 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
COT agenda and papers: 20 March 2007