Food and Behaviour Research

Donate Log In

A randomised controlled trial into the effects of food on ADHD.

Pelsser LM, Frankena K, Toorman J, Savelkoul HF, Pereira RR, Buitelaar JK. (2009) Eur Child Adolesc Psychiatry.  18(1): 12-9. Epub 2008 Apr 21. 

Web URL: View this and related abstracts via PubMed here

Abstract:

The aim of this study is to assess the efficacy of a restricted elimination diet in reducing symptoms in an unselected group of children with Attention deficit/hyperactivity disorder (ADHD). Dietary studies have already shown evidence of efficacy in selected subgroups.

Twenty-seven children (mean age 6.2) who all met the DSM-IV criteria for ADHD, were assigned randomly to either an intervention group (15/27) or a waiting-list control group (12/27). Primary endpoint was the clinical response, i.e. a decrease in the symptom scores by 50% or more, at week 9 based on parent and teacher ratings on the abbreviated ten-item Conners Scale and the ADHD-DSM-IV Rating Scale.

The intention-to-treat analysis showed that the number of clinical responders in the intervention group was significantly larger than that in the control group [parent ratings 11/15 (73%) versus 0/12 (0%); teacher ratings, 7/10 (70%) versus 0/7 (0%)]. The Number of ADHD criteria on the ADHD Rating Scale showed an effect size of 2.1 (cohen's d) and a scale reduction of 69.4%. Comorbid symptoms of oppositional defiant disorder also showed a significantly greater decrease in the intervention group than it did in the control group (cohens's d 1.1, scale reduction 45.3%).

A strictly supervised elimination diet may be a valuable instrument in testing young children with ADHD on whether dietary factors may contribute to the manifestation of the disorder and may have a beneficial effect on the children's behaviour.

FAB RESEARCH COMMENT:

Randomised controlled trials (RCT) provide the highest level of evidence for cause-and-effect relationships. 

These findings therefore add further strong evidence to the proposal that for at least some children with ADHD and related behaviour problems, food allergies or intolerances may be contributing to these difficulties.

Notably, improvements in oppositional and aggressive behaviour - as well as core symptoms of ADHD (inattention, impulsivity and hyperactivity) were also observed.

Previous RCTs have already shown benefits for ADHD symptoms and related behaviour problems in children from dietary interventions involving the exclusion of particular foods, and/or artifcial additives.  See for example:


In practice, the exclusion by parents and carers of some foods from children's diets - notably sweets, many soft drinks, and any highly processed foods containing artificial additives - is likely to be safe, and even advisable, given that these usually have little nutritional value, and healthier alternatives are available.

By contrast, however, the exclusion of major food groups (such as all milk and dairy products, and/or gluten grains) should NOT be undertaken without specialist professional advice to ensure that the diet still provides all essential nutrients.

And for more information on this subject, please see the following list of research articles, which is regularly updated: