A new study published in the January 2010 issue of Pediatrics now estimates that 8.6% of American children and adolescents have attention deficit hyperactivity disorder (ADHD).
This study is based on results from the National Health and Nutrition Examination Survey (NHANES), a collaboration between the National Institute of Mental Health and the National Center for Health Statistics. The survey, which included 3,042 participants from 8 to 15 years of age, also found that boys are more than twice as likely as girls to have ADHD.
Scientists have differing views on reasons behind the dramatic increase in the number of children with ADHD (formerly known as attention deficit disorder and hyperkinesis), which went from 150,000 children in 1970 to 4.5 million by 2003. Some believe that this may be partly due to the expanded definition of ADHD or misdiagnoses resulting from inadequate evaluations, while others suggest there may actually be more hyperactive and inattentive children.
Since genetic changes would not account for this increase, it may be that environmental changes are significantly decreasing our children's ability to concentrate and regulate their own behavior, wrote Sanford C. Newmark, M.D., from the University of Arizona Center for Integrative Medicine, the author of a 2009 scientific review article published in the journal Explore.
In his review, Dr. Newmark cited sensitivities to certain food additives and foods, as well as other nutritional factors, as possible culprits in this rise. Research has shown a consistent relationship to the intake of artificial colors and/or preservatives on the symptoms of ADHD or hyperactivity, he wrote.
After describing two large British studies linking food dyes and preservatives with hyperactivity, including one that was published in the Lancet, he concluded: One can see how the intake of these substances could shift in a positive direction the proportion of children diagnosed with ADHD.
The link between artificial food additives and hyperactivity was first discovered by the late Dr. Ben Feingold, chief of allergy at San Franciscos Kaiser Permanente Medical Center. Dr. Newmark credited Dr. Feingolds clinical research as the first important attempt at nutritional intervention in ADHD and discussed the low-additive Feingold Diet. The nonprofit Feingold Association (www.feingold.org) has been helping thousands of families use this diet since 1976.
Has there been an increase in Americans' consumption of artificial food dyes that might correlate with the rise in ADHD?
In fact, consumption of these dyes has increased almost threefold since the 1980s, rising from about 6.4 million pounds in 1985 to more than 17.8 million pounds in 2005.
Dr. Newmark pointed out that since more and more families have two working parents, family meals increasingly consist of processed (additive-laden) foods. It is hard to know just when a Pop-Tart became an acceptable breakfast, but it often is, he wrote. "School lunches on the whole are abysmal, with an unacceptably high intake of processed foods and saturated fats."
In response to the Lancet study and a meta-analysis of fifteen trials linking artificial food dyes with ADHD, the European Parliament passed legislation requiring labels on foods containing these dyes to warn that they "may have an adverse effect on activity and attention in children." At the urging of the British government, food manufacturers in the United Kingdom are also removing most synthetic dyes from foods sold there.
Here in the United States, the American Academy of Pediatrics acknowledged in its journal, AAP Grand Rounds, that "a trial of a preservative-free, food coloring-free diet is a reasonable intervention" for hyperactive children, and nineteen prominent scientists cosigned a letter calling on Congress to ban these additives.
Dr. Newmark concluded this review by recommending that "all families [whose children have ADHD] eliminate artificial colors and preservatives from their childrens diet as much as possible. He also suggested that these children be checked for food sensitivities, as well as for low iron and zinc levels, all of which have been linked with ADHD.
The Feingold Association
The nonprofit Feingold Association (www.feingold.org) helps families of children with learning and behavior problems to implement the low-additive Feingold Diet. Membership benefits include a handbook on the Feingold Diet, the Pure Facts Newsletter, a Fast Food & Restaurant Guide, a Foodlist & Shopping Guide, a Mail Order Guide, phone and e-mail help-lines, an online chat room, and a message board. The charity's advisory board and board of directors include medical professionals from Stony Brook University, Johns Hopkins University, the University of Rochester, Baltimore's Sinai Hospital, and other institutions.
Individual dietary needs vary and no one diet will meet everyone's daily requirements. Before starting any new diet, check with your doctor or nutritionist.
Merikangas KR, He JP, Brody D, et al. Prevalence and treatment of mental disorders among US children in the
2001-2004 NHANES. Pediatrics. Jan 2010;125(1):75-81 (doi:10.1542/peds.2008-2598).
Newmark SC. Nutritional intervention in ADHD. Explore (NY). May-Jun 2009;5(3):171-4.
McCann D, Barrett A, Cooper A, 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 2007;370(9598):1560-7.
Schab DW, Trinh NT. Do artificial food colors promote hyperactivity in children with hyperactive syndromes? A meta-analysis of double-blind placebo-controlled trials. Journal of Developmental & Behavioral Pediatrics. Dec 2004;25(6):423-434.
Schonwald A. ADHD and Food Additives Revisited. AAP Grand Rounds. DOI: 10.1542/gr.19-2-17, 2008;19;17.
Additional studies can be found at http://www.feingold.org/Research/adhd.html