Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives

Joel T. Nigg, Kara Lewis, Tracy Edinger, Michael Falk

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106 Scopus citations

Abstract

The role of diet and of food colors in attention-deficit/hyperactivity disorder (ADHD) or its symptoms warrants updated quantitative meta-analysis, in light of recent divergent policy in Europe and the United States. Studies were identified through a literature search using the PubMed, Cochrane Library, and PsycNET databases through February 2011. Twenty-four publications met inclusion criteria for synthetic food colors; 10 additional studies informed analysis of dietary restriction. A random-effects meta-analytic model generated summary effect sizes. Restriction diets reduced ADHD symptoms at an effect of g = 0.29 (95% CI, 0.070.53). For food colors, parent reports yielded an effect size of g = 0.18 (95% CI, 0.080.24; p =.0007), which decreased to 0.12 (95% CI, 0.010.23; p <.05) after adjustment for possible publication bias. The effect was reliable in studies restricted to food color additives (g = 0.21, 95% CI = 0.060.36) but did not survive correction for possible publication bias and was not reliable in studies confined to Food and Drug Administrationapproved food colors. Teacher/observer reports yielded a nonsignificant effect of 0.07 (95% CI = -0.03 to 0.18; p =.14). However, high-quality studies confined to color additives yielded a reliable effect (g = 0.22, 95% CI = 0.100.41, p =.030) that survived correction. In psychometric tests of attention, the summary effect size was 0.27 (95% CI = 0.070.47; p =.007) and survived correction. An estimated 8% of children with ADHD may have symptoms related to synthetic food colors. A restriction diet benefits some children with ADHD. Effects of food colors were notable were but susceptible to publication bias or were derived from small, nongeneralizable samples. Renewed investigation of diet and ADHD is warranted.

Original languageEnglish (US)
Pages (from-to)86-97.e8
JournalJournal of the American Academy of Child and Adolescent Psychiatry
Volume51
Issue number1
DOIs
StatePublished - Jan 2012

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Keywords

  • ADHD
  • meta-analysis
  • restriction diet
  • synthetic food color additives

ASJC Scopus subject areas

  • Developmental and Educational Psychology
  • Psychiatry and Mental health

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