ADHD & Diet: How Food Affects Mood

By Michael Jacobson
Issue 101, July/August 2000

In the early 1970s, Dr. Benjamin Feingold, then chief emeritus of the Department of Allergy at the Kaiser Foundation Hospital and Permanente Medical Group in San Francisco, reported a link between diet and several physical and allergic conditions. Thirty to 50 percent of Feingold's hyperactive patients said they benefited from diets free of artificial colorings and flavorings, and certain natural chemicals (salicylates, found in apricots, berries, tomatoes, and other foods).

Although many parents eagerly embraced the Feingold diet, others--such as the processed-food industry, many child-behavior experts, and some pediatricians--were more skeptical. Perhaps, they reasoned, the families were doing other things in addition to dietary modification, or maybe they were simply reacting to wishful thinking. With time, however, researchers began testing aspects of Feingold's claim. Over the following decades, almost two dozen additional controlled trials followed, mostly focusing on food dyes. In some cases, children were put on a diet that lacked many food additives and subsequently "challenged" with dyes. In other cases, the behavior of children was monitored after they were switched to a diet free of certain foods that might cause a reaction (dyes, wheat, egg, chocolate, and others) and then challenged with those foods. Most--but not all--of those studies found that some--but not all--children were affected by diet, some slightly, others dramatically.

In 1982, the National Institutes of Health (NIH) convened a "consensus development conference" on diets and hyperactivity to review the early scientific research and advise health professionals and the public. Their conclusion was that controlled studies "did indicate a limited positive association between. . . [Feingold-type] diets and a decrease in hyperactivity." The panel recommended further broad research on the diet-behavior connection--advice that generally has not been heeded. This is in part why so little is known today about the percentage of children who respond to dietary therapy, to what degree they respond, which children are most likely to be affected, the additives and foods that cause problems, and the best ways to use diet therapy.

Nevertheless, in the face of ever-escalating Ritalin prescriptions, some families are seeking out dietary therapy for their children. One reason for their interest is that Ritalin and amphetamines (such as Adderall and Dexedrine) may cause reduced appetite and weight loss, stomachaches, and insomnia. More seriously, those drugs occasionally may cause or exacerbate tics and Tourette's syndrome. Another drug, Pemoline (Cylert), has been associated with fatal liver failure; the Food and Drug Administration (FDA) urges doctors not to use it to treat ADHD.

Furthermore, until long-term studies are done, it will not be known whether years-long treatment in childhood (or, for that matter, adulthood) with stimulant drugs has an effect on the nervous system or other parts of the body later in life. Importantly, a study by the federal government's National Toxicology Program (NTP) found that doses of Ritalin that only modestly exceeded the maximum recommended dose in humans caused liver tumors in mice. "Millions of young children take Ritalin for years on end, and children may be especially susceptible to a carcinogen's effects," says Samuel Epstein, a cancer expert at the School of Public Health at the University of Illinois. Although the NTP study indicates "a weak signal of carcinogenic potential," the government still considers the drug safe. Yet the lack of a long-range study of Ritalin's possible carcinogenic effect is extremely troubling. Large numbers of children have been consuming Ritalin for only the past one or two decades, and cancer might not manifest itself for several decades later in life.

Trying a Dietary Modification Approach
Parents wishing to test their children's response to diet will seek to identify and remove irritants in foods (and other products) that cause behavioral symptoms. This is done by eliminating certain foods (and vitamins and drugs) from the (unmedicated) child's diet for several weeks to see if his or her behavior is improved. In some cases, dietary changes by themselves may adequately reduce behavioral problems. If not, amphetamines or another medication could be tried in addition to, or instead of, a restricted diet. The goal is to identify the specific foods or additives, if any, that affect your child. What makes this challenging is that children's behavior ordinarily is so variable.

Needless to say, controlling the diets of young children can be difficult, especially once children go to school. Foods containing dyes and other potentially provoking ingredients are advertised aggressively and available everywhere: at supermarkets, restaurants, schools, vending machines, parties, theaters, and the homes of friends and relatives. Many young children are already "hooked" on the very foods that may cause problems, though it is getting easier to find acceptable alternatives. And children who don't eat what all their friends eat may feel left out or stigmatized.

Some parents who've put their children on special diets, though, say their children willingly cooperate in making dietary changes, especially after they discover that those changes make them feel better. Some older children avidly read labels to avoid certain ingredients.