Effects of an elimination diet and a healthy diet in children with Attention‐Deficit/Hyperactivity Disorder: 1‐Year prospective follow‐up of a two‐arm randomized, controlled study (TRACE study)

An Elimination Diet (ED) or Healthy Diet (HD) may be effective in reducing symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD), but long-term maintenance effects and feasibility have never been examined. One-year prospective follow-up of a sample of 165 children (5-12 years) with ADHD randomized (unblinded; 1:1) to 5 weeks treatment with either ED (N = 84) or HD (N = 81) and a non-randomized comparator arm including 58 children being treated with Care as Usual (CAU). Dietary participants were allowed to add or switch to CAU treatment after 5 weeks. The primary outcome was a 5-point ordinal measure of improvement based on both parent and teacher ratings on ADHD and dysregulation problems, determined after 1 year prospective follow-up. Ordinal regression analyses and linear mixed models analyses were conducted on an intention to treat basis. In addition, as-treated analyses were performed. The trial is closed and registered in the Dutch trial registry, number NL5324. At 1 year follow-up, 24% of the participants still complied with the ED and 37% still complied with the HD. In the ED (+CAU) trajectory, fewer participants showed (partial) improvement after 1-year prospective follow-up compared to the HD (+CAU) trajectory (47% vs. 64%, χ2 (4, N = 152) = 11.97, p = 0.018). The HD (+CAU) - but not ED (+CAU) - trajectory had comparable 1-year outcomes compared to the non-randomized CAU-trajectory. Results for secondary outcomes (e.g. health, parental stress) did not differ between the ED (+CAU) and HD (+CAU) trajectories. The prevalence of psychostimulant use was lower in the ED (+CAU) and HD (+CAU) trajectories compared to the non-randomized CAU-trajectory (38%, 45%, 78%, respectively). Predictors for long-term benefit from dietary treatments included high initial severity of ADHD problems, low severity of emotional problems and sufficient parental mental resources. In line with the short-term effects, prospective 1-year follow-up outcomes are in favor of treatment with HD and not ED. Initial 5-week treatment with HD and if needed/preferred followed by CAU may reduce psychostimulant use without negatively impacting 1-year outcomes.