ADHD researchers: elimination diet has dramatic results

A highly restricted diet can cause rapid improvement in symptoms of attention deficit hyperactivity disorder (ADHD) in children, according to a study by researchers in the Netherlands. In addition, they report, the diet can markedly reduce symptoms of oppositional defiant disorder (ODD).

Lidy Pelsser and colleagues selected study participants from a consecutive series of Dutch children referred to an ADHD research center. The 27 children, who ranged in age from 3 to 8, were divided into an intervention group of 15 children and a waiting-list group of 12 children. (One child in the control group and two in the intervention group did not complete the study.) The intervention group ate a very restricted “elimination” diet consisting of rice, turkey, lamb, vegetables, fruits, margarine, vegetable oil, tea, pear juice, and water, while the control group ate a typical diet.

Both groups of children underwent testing at three points: at the beginning of the study, after a two-week baseline in which all children ate a typical diet, and after five weeks of the active study condition. Parents and teachers scored the children on the Abbreviated Conners Scale (ACS) and the ADHD-DSM-IV Rating Scale (ARS).

The researchers report, ”At the end of the trial the mean scores in the intervention group showed a 62.6 percent improvement on the ACS and a 70.3% improvement on the ARS number of ADHD criteria.” The control group, in contrast, showed no improvement. Children in the treatment group exhibited both improved attention and reduced hyperactivity and impulsivity.

“According to the parent ratings,” the researchers say, “11 of 13 children (85 percent) in the intervention group who completed the study showed an improvement of 50 percent or more.” These responders, Pelsser and colleagues say, no longer met criteria for ADHD. Teachers scored 7 of 10 children in the treatment group as responders (teacher ratings for the other children were not available), while they scored none of the control-group children as responders.

At the beginning of the trial, 12 of the children in the treatment group and 10 in the control group met criteria for ODD, a disorder characterized by frequent temper tantrums, anger, resentment, and active defiance of adults. By the end of the trial, only 4 of the children in the intervention group met criteria for ODD, while all of the 10 children in the control group still did so.

The researchers say their results are consistent with other studies, noting, “All controlled trials on ADHD and foods using a few foods diet show a more or less beneficial effect on the behavior of the subjects.” They note that the extent of the restrictions may play a significant role in how effective this intervention is for children with ADHD.

They also note the significance of the surprising reduction in ODD, saying, “We expected the children in the intervention group to show deterioration of their ODD behavior, opposing the dietary restrictions which they surely would not like.”

Pelsser and colleagues note that their study was limited by the impossibility of keeping parents and teachers uninformed as to which children participated in the intervention. They also acknowledge that the elimination diet may be hard for children to follow, but they note that new foods can be added to the diet gradually in order to determine which foods cause problems.