Prevalence of Artificial Food Colors in Grocery Store Products Marketed to Children

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, 0.07-0.53). For food colors, parent reports yielded an effect size of g = 0.18 (95% CI, 0.08-0.24; p = .0007), which decreased to 0.12 (95% CI, 0.01-0.23; p < .05) after adjustment for possible publication bias. The effect was reliable in studies restricted to food color additives (g = 0.21, 95% CI = 0.06-0.36) but did not survive correction for possible publication bias and was not reliable in studies confined to Food and Drug Administration-approved 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 = 0.10-0.41, p = .030) that survived correction. In psychometric tests of attention, the summary effect size was 0.27 (95% CI = 0.07-0.47; 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. Copyright © 2012 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

This article is intended to provide a comprehensive overview of the role of dietary methods for treatment of children with attention-deficit/hyperactivity disorder (ADHD) when pharmacotherapy has proven unsatisfactory or unacceptable. Results of recent research and controlled studies, based on a PubMed search, are emphasized and compared with earlier reports. The recent increase of interest in this form of therapy for ADHD, and especially in the use of omega supplements, significance of iron deficiency, and the avoidance of the "Western pattern" diet, make the discussion timely. Diets to reduce symptoms associated with ADHD include sugar-restricted, additive/preservative-free, oligoantigenic/elimination, and fatty acid supplements. Omega-3 supplement is the latest dietary treatment with positive reports of efficacy, and interest in the additive-free diet of the 1970s is occasionally revived. A provocative report draws attention to the ADHD-associated "Western-style" diet, high in fat and refined sugars, and the ADHD-free "healthy" diet, containing fiber, folate, and omega-3 fatty acids. The literature on diets and ADHD, listed by PubMed, is reviewed with emphasis on recent controlled studies. Recommendations for the use of diets are based on current opinion of published reports and our practice experience. Indications for dietary therapy include medication failure, parental or patient preference, iron deficiency, and, when appropriate, change from an ADHD-linked Western diet to an ADHD-free healthy diet. Foods associated with ADHD to be avoided and those not linked with ADHD and preferred are listed. In practice, additive-free and oligoantigenic/elimination diets are time-consuming and disruptive to the household; they are indicated only in selected patients. Iron and zinc are supplemented in patients with known deficiencies; they may also enhance the effectiveness of stimulant therapy. In patients failing to respond or with parents opposed to medication, omega-3 supplements may warrant a trial. A greater attention to the education of parents and children in a healthy dietary pattern, omitting items shown to predispose to ADHD, is perhaps the most promising and practical complementary or alternative treatment of ADHD.

The effect of artificial food colors (AFCs) on child behavior has been studied for more than 35 years, with accumulating evidence from imperfect studies. This article summarizes the history of this controversial topic and testimony to the 2011 Food and Drug Administration Food Advisory Committee convened to evaluate the current status of evidence regarding attention-deficit/hyperactivity disorder (ADHD). Features of ADHD relevant to understanding the AFC literature are explained: ADHD is a quantitative diagnosis, like hypertension, and some individuals near the threshold may be pushed over it by a small symptom increment. The chronicity and pervasiveness make caregiver ratings the most valid measure, albeit subjective. Flaws in many studies include nonstandardized diagnosis, questionable sample selection, imperfect blinding, and nonstandardized outcome measures. Recent data suggest a small but significant deleterious effect of AFCs on children's behavior that is not confined to those with diagnosable ADHD. AFCs appear to be more of a public health problem than an ADHD problem. AFCs are not a major cause of ADHD per se, but seem to affect children regardless of whether or not they have ADHD, and they may have an aggregated effect on classroom climate if most children in the class suffer a small behavioral decrement with additive or synergistic effects. Possible biological mechanisms with published evidence include the effects on nutrient levels, genetic vulnerability, and changes in electroencephalographic beta-band power. A table clarifying the Food and Drug Administration and international naming systems for AFCs, with cross-referencing, is provided.