Research Offers Little Support for
Bethesda, Md--Seven years after one pediatrician's prescription for treating hyperactive children with an additive-free diet raised the hopes of parents and teachers that a solution to the troubling and mysterious syndrome was at hand, medical experts still have little scientific evidence that the "defined" diets improve the behavior of such children.
During a conference here recently sponsored by the National Institutes of Health, physicians, researchers, parents, and educators explored the apparent discrepancies between scientific studies, most of which show that the additive-free diet has little effect on hyperactive behavior, and reports of parents, many of whom say that the diet had dramatic effects on the behavior of their hyperactive children.
Some pediatricians also favor the use of defined diets in treating such children.
At the gathering's conclusion, the panel of medical experts released a "draft" formal statement saying diet "should not be universally applied to the treatment of childhood hyperactivity at this time."
But, stressing that treatment of hyperactivity should be tailored to each individual child, the panel noted that it recognized that diet remains one of several options for treatment.
Also attending the conference was Ben F. Feingold, the doctor who first reported that hyperactive children became significantly less so when placed on a diet that was free of artificial additives and certain naturally occuring substances.
His report was greeted with some skepticism by the medical community, but in the ensuing years, thousands of parents have reported that their hyperactive children's behavior underwent a dramatic reversal after they began following the diet.
Dr. Feingold, who has never claimed that the diet will help all hyperactive children, argued in favor of his thesis at the conference.
The panel, however, while not discounting the possible value of the diet, avoided endorsing either the diet, or any other method of treatment, noting instead that "...an initial trial of dietary treatment or a continuation of a diet in patients whose families and physicians perceive benefits may be warranted" if used after "thorough and appropriate" evaluation of the child and consideration of other treatment methods. Treatment, the panel emphasized, must be tailored to the individual child.
One in Five Affected
The panel's recommendations clarify but do not eliminate the questions that surround the treatment of hyperactivity, a childhood disorder first recognized in 1902 and now, according to some estimates, affecting as many as one in five children.
The problem is a significant one for educators in two ways. School officials must deal with a hyperactive child's behavior in the classroom, and, since hyperactive children are often labeled "learning disabled" as well, officials are often faced with the additional problem of whether to place such children in special-education programs.
The controversial diets are the most recent innovation in the treatment of such children, whose symptoms of uncontrollable and disruptive behavior lead to the diagnosis that they are hyperactive.
Other methods of treatment include medications--tranquilizers and amphetamines. But these have also been sources of controversy--too-high doses of tranquilizers may cause a child to become a "zombie," and many parents prefer not to have their child's behavior regulated by chemicals.
According to the theory behind the diets, some hyperactive children are extremely sensitive to some substances, and, when exposed to the substances, display the symptoms of hyperactivity.
By eliminating the substances from the children's diets, their hyperactive behavior is reduced, according to Dr. Feingold.
The "Feingold diet," on which much of the conference discussion focused, is the most common of these "defined diets." It excludes virtually all artificial colorings, flavorings, and preservatives.
Food additives like artificial dyes and flavors are relative newcomers to the human diet, Dr. Feingold said. Hence, he theorizes, as compounds that are not a "natural" part of the human diet, these substances could cause adverse reactions in sensitive individuals.
Dr. Feingold's initial reports of the diet's effectiveness, however, and the many that have followed since, are essentially "anecdotal," conference participants pointed out. None of the reports of overwhelming effectiveness are based on controlled, scientific studies, according to panelists, although a few studies have suggested that the diet has some effect.
Lacking "hard" data, many members of the medical community remain doubtful; the diets may work, but their effect may be due to the power of suggestion or other factors that have nothing to do with the presence or absence of food additives, several speakers said.
Dr. Feingold said at the conference that between 40 and 50 percent of all hyperactive children could be helped by the diet--if it were followed rigidly. The child would re-main hyperactive, he said, if he or she indulged in forbidden foods. And for some hyperactive children, he said, the diet is simply not effective.
The diet, according to its proponents, has produced marked changes in children whose extremely high levels of activity made them unmanageable both at home and in the classroom. In many cases, these children had previously been treated with powerful medications like amphetamines. After following the diet, the children no longer required the medications, according to these reports.
Efforts to reproduce these effects under controlled conditions, however, have so far met with little success. The panel noted, "While differences and inadequacies in the design of the various control studies make analysis difficult, studies indicate a limited positive association between the defined diet and decrease in hyperactivity."
Numerous researchers have tried placing children identified as hyperactive on defined diets--usually a variation of the Feingold diet--then "challenging" them by giving them cookies that contain large amounts of artificial colorings to see if the children became demonstrably more hyperactive.
Two studies carried out in the late 1970's by J. Preston Harley of the University of Wisconsin tested the effects of artificial food coloring on 36 school-age children who had been identified as hyperactive.
Although some parents reported differences in their children's behavior, a follow-up study failed to show any behavioral differences between those children who had received food additives and those who had not.
The results of these two studies generally failed to support claims for the diet's effectiveness, according to Dr. Esther Wender, a pediatrician specializing in the treatment of hyperactivity who described the studies at the conference.
"The fact remains that the parents saw something," she said. "I do not think that the evidence was evidence of dramatic response. If there was a response, it was not in the 40-to-60 percent range, and it was very subtle."
Other studies, including several by C. Keith Conners, a researcher with Children's Hospital in Washington, who spoke at the conference, have shown that under controlled circumstances, the diet has slight but definite effects on some children.
Dr. Conners and others have reported that the diet seems to be more effective in treating younger children. One possible reason for this, he said, may be that the diets of very young children can be controlled better; the child cannot sneak off and eat prohibited foods.
Other researchers have detected no positive effects when hyperactive children were placed on defined diets, according to several speakers at the conference.
Researchers agree, however, that it is nearly impossible to design a controlled study that tests the effects of the diets, since there are so many possible substances to consider.
Most of the studies to date have tested the effects of food colorings rather than flavorings, because their presence is more easily masked.
In contrast to the laboratory findings, which offer very modest evidence of efficacy, come the reports of parents, whose formerly intractable children improved dramatically after several weeks on the diet. Jane Hersey, president of the Feingold Association of the United States, noted that "although some would argue that the scientific evidence is lacking," the diet had nevertheless helped thousands of children, including her own daughter. The Feingold Association is a national nonprofit group, composed of parents and others interested in the diet, with about 20,000 members.
Other parents and pediatricians also spoke in favor of the diet at the conference.
But given the absence of hard evidence to support the diet's effectiveness, the nih panel stressed, all "treatment options"--including diet, medications, behavior modification, and psychotherapy--should be considered.