Food colours

Study finds no link between food colours, ADHD

There is not enough scientific data to support a link between FDA-approved food colours and the increased incidence of attention-deficit/hyperactivity disorder (ADHD), according to results of a new meta-analysis published in the Journal of the American Academy of Child & Adolescent Psychiatry.

The results indicate food colours may promote ADHD symptoms, but when the data is limited to FDA-approved colours, the link is no longer reliable.

For the meta-analysis, researchers at the Oregon Health and Science University and the International Life Sciences Institute (ILSI) identified studies through a literature search using the PubMed, Cochrane Library and PsycNET databases through February 2011. Twenty-four publications met inclusion criteria for synthetic food colours; 10 additional studies informed analysis of dietary restriction. A random-effects meta-analytic model generated summary effect sizes.

Data suggested information from parents indicate an effect of food colours on ADHD; however, it was not found to be a reliable link when teacher input was calculated or when the analysis was limited to FDA-approved food colours.

They found an estimated 8% of children with ADHD may have symptoms related to synthetic food colours. The researchers noted renewed investigation of diet and ADHD is warranted.

The European Commission asked the European Food Safety Authority (EFSA) in 2010 to re-evaluate the safety of all previously authorised food additives, including colours, by 2020, taking into account the latest science. Based on EFSA’s scientific advice, the European Commission and Member States may decide together to change the uses of additives or if needed to remove them from the EU list of authorised food additives in order to protect consumers. Food colours are being re-evaluated first as they were among the first additives to be authorised for use in the EU.

The US has two main categories of food colour additives: certified and exempt. According to FDA, colour additives are safe when used properly. The FDA allows the use of colours that it knows have “a reasonable certainty of no harm” for the intended use. Colour additives that have been found to cause cancer in animals or humans are not allowed for use in FDA-regulated products.

Controversy over the safety of artificial food colours has been raging for years, but reached a new frenzy in 2007 following the publication of a highly controversial study conducted by the University of Southampton in the UK suggesting a link between six food dyes – the ‘Southampton Six’ – and hyperactivity in children.

While EFSA concluded that the results could not be used as a basis for altering the acceptable daily intakes of the colours in question, the European Parliament baffled many observers by insisting that products featuring the colours should nevertheless include warning labels noting that they “may have an effect on activity and attention in children”.

However, the US FDA Food Advisory Committee has voted against recommending European-style warning labels on products containing artificial food colours in the US.

Journal Reference:

Meta-Analysis of Attention-Deficit/Hyperactivity Disorder or Attention-Deficit/Hyperactivity Disorder Symptoms, Restriction Diet, and Synthetic Food Color Additives

Journal of the American Academy of Child & Adolescent Psychiatry

Volume 51, Issue 1 , Pages 86-97.e8, January 2012

Additional reading:

“Food colours and ADHD” – Food Product Design