The question that parents often ask is, “Can diet restriction benefit children with attention-deficit/hyperactivity disorder?” It appears the answer is, as I wrote in my book, Why ADHD Doesn’t Mean Disaster … yes! … at least in some cases.
What’s the bottom line? In small studies, restricting the diet of children with attention-deficit/hyperactivity disorder (ADHD) will produce a modest improvement in symptoms in some of them.
About 1 in 12 children may be sensitive to synthetic food colors. The data in this area are relatively weak and inconsistent; however, diet restriction can be tried, especially if parents wish to avoid stimulants.
Synopsis The theory that synthetic food colors affects ADHD has been around for over 40 years without good evidence. However, web sites are common that explain the “Feingold diet,” which is a diet restriction to avoid food colors. These authors searched three databases, including the Cochrane Library, to find studies of either a restriction diet or crossover studies of specific food colors.
They found 6 randomized, controlled studies of 164 children that restricted food colors and/or other additives, finding that about 33% of children had a 25% or greater improvement in symptoms (95% CI 19% – 52%), with results similarly when comparing parent or teacher ratings. In studies that specifically added and then removed food colors (crossover trials), there was a small effect on symptoms, with the authors estimating that about 8% of children with ADHD may have symptoms related to synthetic food colors. The studies are small, the effects also small, and the risk of bias is high with these studies, and the level of proof would not be sufficient for less innocuous treatment approaches.
Reference Nigg JT, Lewis K, Edinger T, Falk M. Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. J Am Acad Child Adolesc Psychiatry 2012;51(1):86-97. [Link to free full-text J Am Acad Child Adolesc Psychiatry article PDF | PubMed® abstract]