From Our 2008 Archives

Experts Revisit Food Additives and ADHD

Research Suggests Limiting Food Additives in Diet May Help Kids With ADHD

By Salynn Boyles
WebMD Health News

Reviewed By Louise Chang, MD

May 22, 2008 — The notion that artificial colors and preservatives in foods may play a role in hyperactivity has been largely dismissed within conventional medicine, but there are signs that this is beginning to change.

In a newly published editorial appearing in BMJ, pediatrics professor Andrew Kemp, MD, of the University of Sydney, called for removal of food additives from the diet to be part of standard initial treatment for kids with attention deficit hyperactivity disorder (ADHD).

Kemp cited a recent controlled trial showing an increase in hyperactivity among children without ADHD who were fed a diet high in food colorings and the preservative sodium benzoate.

Last February, editors of the American Academy of Pediatrics publication AAP Grand Rounds cited the same study as evidence that it is time to revisit the issue.

"The overall findings of the study are clear and require that even we skeptics, who have long doubted parental claims of the effects of various foods on the behavior of their children, admit we might have been wrong," the editors wrote.

Kemp tells WebMD that practitioners have largely ignored the clinical evidence suggesting that dietary modification improves ADHD symptoms in some children.

"Clearly it doesn't work for everybody, but very few treatments do," he says. "(Dietary modification) is certainly something that parents who want to avoid drugs could try for a month or six weeks."

Additives and ADHD

In the United States, 4.7 million children, including 9.5% of boys and 5.9% of girls, have ever been diagnosed with ADHD, according to the latest statistics from the CDC.

Stimulant medications such as Ritalin and Adderall are the most commonly prescribed treatments for hyperactivity, but family and behavioral therapy is also used.

In his editorial, Kemp argues that there is more research suggesting a benefit for dietary modification than for behavioral therapy, yet dietary modification has been widely dismissed as an alternative treatment.

He notes that of 22 studies conducted between 1975 and 1994, 16 found dietary modification to have a positive impact on at least some children with ADHD.

"In view of the relatively harmless intervention of eliminating colorings and preservatives, and the large number of children taking drugs for hyperactivity, it might be proposed that an appropriately supervised and evaluated trial of eliminating colorings and preservatives should be part of standard treatment for children," Kemp writes.

Food Additives on Trial

The 2007 study cited by Kemp and the AAP editors included 297 British children from the general population who were either age 3 or between the ages of 8 and 9 and whose diets were closely controlled for six weeks.

During the study, the children drank either beverages with food additives or a placebo drink with no additives.

Neither the children nor the researchers knew which beverage the children were getting.

The children were evaluated for inattention and hyperactivity by parents and teachers and through a standardized computer testing.

The researchers reported that for both age groups evaluated, children who drank the beverages with the artificial additives exhibited more hyperactivity and shorter attention spans.

That 2007 study aside, pediatrician Mark Wolraich, MD, tells WebMD that most studies that have examined the impact of limiting food additives on ADHD are at least three decades old, and these studies showed benefits in only a small percentage of hyperactive children.

A professor of pediatrics at the University of Oklahoma Health Sciences Center, Wolraich notes that removing preservatives from many foods might pose a health problem of its own.

"The preservatives keep the food from spoiling, so there would be less food available if we removed them from all foods," he says.

Seattle Children's Hospital associate medical director Edgar Marcuse, MD, says the new study is more rigorous than any research that has been done before, even though it was not limited to children with ADHD.

As an editor of AAP Grand Rounds, Marcuse co-wrote the editorial calling on clinicians to be more open-minded about a possible role for dietary restrictions in the treatment of hyperactivity.

"This was not a huge study, but the overall findings were rather compelling," Marcuse tells WebMD. "We don't know what this means for any individual child at this point, but I think it reopens a book that has been closed."

SOURCES: Berg, K.M, American Journal of Medicine, May 2008; vol 121: pp 406-418. Karina M. Berg, MD, assistant professor of medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, N.Y. Ethel Siris, MD, president, National Osteoporosis Foundation; professor of clinical medicine, Columbia University, New York. Siris et al., The Journal of the American Medical Association, Dec. 12, 2001; vol 286: pp 2815-2822.Kemp, A. BMJ, May 24, 2008; vol 336: p 1144. Andrew Kemp, MD, professor of pediatric allergy and clinical immunology, Department of Allergy and Immunology, Children's Hospital at Westmead, University of Sydney, Sydney, Australia. Schonwald, A., AAP Grand Rounds, February 2008. Eigenmann, P.A., The Lancet, Nov. 3, 2007; vol 370: pp 1560-1567. National Center for Health statistics Fast Stats: "Attention Deficit Hyperactivity Disorder (ADHD)." Mark Wolraich, MD, CMRI-Shaun Walters Professor of Pediatrics, University of Oklahoma Health Sciences Center. Edgar Marcuse, MD, general academic pediatrician and professor, University of Washington; associate medical director, Seattle Children's Hospital; editor, AAP Grand Rounds.

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