Attention deficit hyperactivity disorder (ADHD) is among the most common childhood behavioural disorders, causing significant impediment to a child’s development. Treatment options are limited, and medication use is associated with side-effects and concerns about long-term effects. Large improvements in ADHD symptoms have been observed in more than half of the children after following a few-foods diet (FFD); we refer to these children as "responders". However, this diet requires an enormous effort of both the child and parents, limiting its applicability as an ADHD treatment.
An FFD approach, i.e. first following the FFD, then gradually adding foods one by one in FFD responders, is burdensome and time consuming. Therefore, the FFD approach is only successful in families with an organized family structure and a strong motivation to follow the diet. To make the FFD approach more feasible, we need to understand how and in which children an FFD improves ADHD symptoms.
The aim of the BRAIN study is to identify the mechanism(s) underlying the positive effect of an FFD on responders, and to identify biomarkers that predict a favourable response to an FFD. The study is an open-label trial with researchers blinded to changes in ADHD symptoms during sample processing and primary data analyses. One-hundred right-handed boys meeting the DSM-IV criteria of ADHD, aged 8 up to and including 10 years, and not receiving ADHD treatment are included. After a 2-week baseline period (regular diet), participants will follow a 5-week personalised FFD preceded by a 1-week transition period.
Data from behavioural questionnaires, functional magnetic resonance imaging (fMRI) and blood, urine, saliva and stool samples will be collected before and after the FFD intervention to investigate if and how an FFD affects brain function and behaviour, including ADHD, via the complex network of communication between the microbiota, gut and brain.