ADHD and elimination diets: a systematic review of the literature

The relationship between ADHD and diet has been a topic of interest for several decades. Early studies used a standardized approach to determine the effects of artificial food additives, primarily specific food colours, on ADHD-related behaviours. More recently, an individualized, approach has been increasingly used that examines the effects of specific culprit foods on individuals. This review first examines studies using a systematic historical approach. A meta-analysis is then applied that examines the differences in effect sizes when differences in individualized versus standardized diet approaches are employed. In addition, effect sizes are examined by the characteristics of the study samples, the type of outcome measure used and whether or not a positive response to a diet trial was used as a criterion for participation in the challenge portion of the studies. Results are also compared to previous meta-analyses that have examined the relationship between diet, food additives and ADHD.