ADHD studies reveal nutritional impact

Parents who have children who are diagnosed with ADHD have tried alternative remedies to deal with the behavioral impact of ADHD.

Interest in the topic of additives has been reignited by a well-designed study in Britain, not least because its results convinced the United Kingdom’s Food Standards Agency (roughly equivalent to the FDA) to urge food manufacturers to remove six artificial coloring agents from food marketed to children in Britain.

The researchers designed a randomized, double-blind, placebo-controlled study to test the effects of the preservative sodium benzoate and six artificial on hyperactivity in 153 preschoolers (who were old) and 144 elementary students (who were 8 or 9 years old). The researchers intentionally conducted the study in a community sample of healthy children, rather than restricting it to those diagnosed with ADHD. But they did ask teachers to fill out a questionnaire to assess hyperactivity for the children at the start of the study, to provide some baseline measures.

For six weeks, the children consumed foods and drinks free of sodium benzoate and the six coloring agents. At weeks 2, 4, and 6, the children consumed plain juice (placebo) or juice containing one of two additive mixes every day for a week.

Mix A contained the preservative plus the colorings sunset yellow, carmoisine, tartrazine, and ponceau 4R; mix B contained the preservative plus sunset yellow, carmoisine, quinoline yellow, and allura red AC.

The drinks had the same flavor and color from one week to the next, but contained different amounts of the added mix. For the older children, the daily amount of additives in mix A equaled the amount of food coloring found in two bags of candy, while the daily amount in mix B was equivalent to four bags of candy.

The researchers asked parents and teachers to assess the children’s behavior using standard clinical instruments, and also asked independent reviewers to observe the children at school. The older children were also assessed with the Conners’ Continuous Performance Test II, which uses visual cues to assess attention and hyperactivity.

The investigators found a mild but significant increase in hyperactivity in both age groups of children — across the board, regardless of baseline hyperactivity levels — during the weeks when they consumed drinks containing artificial colors. This replicated findings of an earlier study they did in 3-year-old children. Using a complex calculation of “effect size,” the investigators estimated that the additives might explain about 10% of the behavioral difference between a child with ADHD and one without the disorder.

This was similar to the effect size reported in an earlier meta-analysis conducted by researchers at Columbia University and Harvard University. Their analysis of 15 trials evaluating the impact of artificial food coloring suggests that removing these agents from the diets of children with ADHD would be about one-third to one-half as effective as treatment with methylphenidate (Ritalin).

Parents could try eliminating the major sources of artificial colors and additives — candy, junk food, brightly-colored cereals, fruit drinks, and soda — from their child’s diet for a few weeks, to see if symptoms improve.


Havard News.

McCann D, et al. “Food Additives and Hyperactive Behaviour in 3-Year-Old and 8/9-Year-Old Children in the Community: A Randomised, Double-Blinded, Placebo-Controlled Trial,” Lancet (Nov. 3, 2007): Vol. 370, No. 9598, pp. 1560–67.

Schab DW, et al. “Do Artificial Food Colors Promote Hyperactivity in Children with Hyperactive Syndromes? A Meta-Analysis of Double-Blind Placebo-Controlled Trials,” Journal of Developmental and Behavioral Pediatrics (Dec. 2004): Vol. 25, No. 6, pp. 423–34.

Weber W, et al. “Complementary and Alternative Medical Therapies for Attention-Deficit/Hyperactivity Disorder and Autism,” Pediatric Clinics of North America (Dec. 2007): Vol. 54, No. 6: pp. 983–1006.

Another perspective on diet and ADHD, from Attention Magazine (published by CHADD):

For more references, please see

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