CABI Blog

So, food colourants cause hyperactivity in children. Or do they? Today’s news about the food colourants study undertaken at the University of Southampton in the UK highlights just how carefully studies need to be designed and how even more care needs to be taken in interpreting the results.

When I settled down to write this news story for www.nutritionandfoodsciences.org this morning, little did I realise that by lunchtime I would be tangled up in a web of confusion. ‘Parents seem to be given enough conflicting advice about what is good or bad for their children without headlines like these’, I thought. It wasn’t until I got to the end of the press release from the University of Southampton and the ‘medicalnewstoday’ story that the real advice materialised. What the authors and the FSA were actually saying was that parents and doctors that encounter signs of hyperactivity or attention deficit in children might simply consider trying to remove foods containing artificial colourings from their diets. Literally like taking candy from a baby. Nobody, as yet, is suggesting that we immediately find alternative colours or eat grey food.

The reasons why this story appears to have been reported upside down are as complex as the causes of hyperactivity in children and in adults. It is this complexity that makes the results of the study so variable.

Andrew Wadge, the FSA’s chief scientist has already covered the paper with great dexterity in his blog, ‘Hungry for Science’, so I won’t go into great depth here.

However, there are a couple of brief points that I would like to add to Wadge’s list and the comments that have been appearing on his blog all day.

Firstly, the paper was authored by a group of psychologists and paediatricians. Where were the food scientists, nutritionists and the other people who generally do have an idea of how many lollipops and bottles of fizzy pop your average child consumes every day? Southampton University has an excellent reputation for human nutrition, yet the effects of food additives on aspects of behaviour clearly did not merit recruiting even one member of the Institute of Human Nutrition to the team, even for the sake of respectability.

Secondly, the trial’s design left the results inherently difficult to interpret. The differences in the two cocktails of additives given to the children varied in respect of which additives were used, such that the placebo was pitted against either a mixture of tartrazine/ponceau 4R or a Quinoline yellow/allura red blend. There was no possibility to single out any one, or even two additives for further inspection. The only things that can be said with any confidence are that these two specific blends may be linked to an increase in hyperactivity in some children and that these results support those of an earlier study conducted on the tartrazine/ponceau 4R based cocktail. Wadge hints in his blog that the the data can only be really understood when transmitted at high frequency into the highly tuned ears of toxicologists, but maybe that’s just the way I interpreted it.

That said, I will leave the last word on the subject to Dr. Wadge, whose blog I would recommend.

If you’re seriously interested in the academic issues involved, my colleague, Isobel Hoskins has spent the best part of her day preparing a CAB Abstracts search specifically to address this topic. Subscribers can find this in the ‘In Brief and In Depth’ section of www.nutritionandfoodsciences.org.