Nutrition Action Healthletter
March 2000 — U.S. Edition 
Ritalin: Is it safe?

While stimulant drugs can help keep a child’s hyperactivity under control, they can also have side effects like reduced appetite, weight loss, stomachaches, insomnia...or worse.

   In a 1995 study by the government’s National Toxicology Program (NTP), the most popular ADHD drug, methylphenidate (Ritalin), caused malignant liver tumors in male mice and benign liver tumors in female mice.1
(It had no effect on rats.)

   What’s especially worrisome is that the amount of Ritalin that caused the cancers was equivalent to as little as two-and-one-half times the maximum recommended dosage in humans. Although there is no evidence that methylphenidate causes cancer in humans, no good studies have been done. (Amphetamines, the active ingredient in Adderall and some other ADHD drugs, didn’t cause cancer in animals.)

   “Since millions of children take Ritalin for long periods of time, it would be prudent to discourage doctors from prescribing the drug, especially in the absence of an explicit warning about the cancer risk,” says Samuel Epstein, professor of occupational and environmental health at the University of Illinois Medical Center in Chicago.

   The Food and Drug Administration acknowledges that the NTP findings constitute “a weak signal of carcinogenic potential,” but it still considers Ritalin safe and has not required more testing. Last October, Epstein and several other cancer experts asked the government to require more testing of methylphenidate and to let the public know that the drug may cause cancer.

1 Toxicology 103: 77, 1995.

If you have a child with ADHD or another behavioral problem, your decision usually boils down to “drugs or no drugs.”

   “It makes a lot more sense to try modifying a child’s diet before treating him or her with a stimulant drug,” says Marvin Boris, a Woodbury, New York, pediatrician whose 1994 study found that diet affected the behavior of his young patients who had both ADHD and food allergies.2

   “The first step is to get on a good elimination diet that does away with the most common allergenic foods and all dyes and preservatives,” explains Boris. If your child’s behavior improves after several weeks, add back foods, one at a time, until you find ones that worsen your child’s behavior. Those foods go on the list of no-nos.

   If changing your child’s entire diet seems too daunting, at the very least try removing foods and other products—like vitamins and toothpaste—that contain food dyes. “Dyes have no essential place in kids’ diets,” says Ohio State’s Eugene Arnold.

   Some studies suggest that preschool children and children who suffer from asthma, eczema, hives, or hay fever respond best to dietary therapy.

   Of course, changing diets isn’t easy. “But kids with peanut allergies manage just fine,” says Tufts University’s Susan Roberts. “Families with children with behavioral problems can do the same thing.” Working with a sympathetic dietitian can make a big difference.

2 Annals of Allergy 72: 462, 1994.

Additional Resources:

• “Diet, ADHD & Behavior”
   This section of the CSPI Web site includes a report and parents’ guide by CSPI.

• The Feingold Association
   This Web site is dedicated to helping children and adults apply proven dietary techniques for better behavior, learning and health.


It’s enough to drive you up the wall. Jacob or Emily doesn’t seem to be able to concentrate on anything for more than a couple of seconds. Sitting still in class—not to mention doing homework—is next to impossible.

   What’s the problem? For a growing number of kids, it’s attention deficit hyperactivity disorder (ADHD)—the most commonly diagnosed behavioral problem in children in the U.S. An estimated three to five percent of all children suffer from the reduced attentiveness and concentration, excessive activity, distractibility, and impulsiveness that are its most common signs. That’s one child for every classroom in the country.

   What are we doing to treat those kids? Spend lunchtime in the nurse’s office of any school and you’ll see, as youngsters trickle in for their pills. Since 1990, sales of drugs like Ritalin have increased five-fold.

   While the drugs usually help relieve the symptoms of ADHD, many parents worry that their children may become dependent. They’re also concerned about side effects like weight loss and insomnia. And there’s disturbing evidence that Ritalin, the most popular stimulant drug that’s used to treat ADHD, causes cancer in laboratory animals (see “Ritalin: Is it Safe?”).

   Is there a safer way to treat hyperactivity? At least part of the answer may lie not in the medicine cabinet, but on the dinner plate and in the snack-food aisle.

How It Started

   The idea that food can affect children’s behavior gained popularity in the early 1970s, when California allergist Benjamin Feingold claimed that the behavior of many of his young patients improved when he placed them on special diets to treat their food allergies. Feingold blamed food additives—especially food dyes—as well as salicylates, which are chemicals that occur naturally in most fruits.

   Since then, 23 good studies have looked at whether food dyes or ordinary foods worsened behavior in children with ADHD or other behavioral problems. A few of the studies compared regular diets to ones free of additives like food dyes, preservatives, and caffeine. Others put kids on highly restricted diets and then “challenged” them by feeding them food dyes or foods—like milk or wheat—that typically cause food allergies.

   In all the studies, the capsules, foods, and meals tested on the children sometimes contained food additives or suspect foods and sometimes didn’t. Neither the children nor the parents, teachers, or psychologists who rated the children’s behavior knew who was getting what until after the studies were completed. That made it less likely that the adults’ expectations influenced the results.

   “Some of these studies demonstrated significant improvement in the behavior of children when their diets were changed, or deterioration in their behavior when they were given food dyes or other offending foods,” says Eugene Arnold, professor emeritus of psychiatry at Ohio State University. But in other studies, the improvements were small, and in a few there were none.

   The studies leave some important questions unanswered:

   1. How many kids are affected by diet?
   Nobody knows. The results varied widely from one study to another—no surprise, since the researchers tested different additives or foods on kids with different problems. What’s more, even if, say, half the children in these studies consistently reacted to diet, you couldn’t conclude that half of all kids with ADHD or other behavioral problems would. Youngsters usually qualified for the studies because their parents or preliminary tests suggested that they were sensitive to food. So they may not be typical.

   2. Which kids are affected by diet?
   Nine of the 23 studies looked only at children with typical ADHD. In eight of them, the behavior of at least some children either worsened after they consumed food dyes or improved when they ate an additive-free diet.

   The other 14 studies looked at children who suffered from ADHD plus asthma, eczema, or food allergies; non-ADHD behavioral problems like irritability and sleep disturbances; or more severe behavioral or neurological disorders.

   In ten of the 14 studies, some of the children improved when they ate diets free of additives or certain foods. And some deteriorated—for example, they got more irritable—when they ate food dyes or foods like corn, wheat, milk, soy, oranges, eggs, or chocolate.

   3. How much of a difference can diet make?
   In some of the nine studies on children with typical ADHD, the behavior of kids who were put on an additive-free diet returned to normal (as rated by their parents or teachers).1,2

   But don’t expect miracles. ”Parents who are looking for a magic bullet may be frustrated,” says researcher Bonnie Kaplan of the University of Calgary, who conducted one of the best studies.3 Changes in diet don’t produce as dramatic or consistent results as ADHD drugs.

   “Diet really does make a difference for a relatively small number of kids,” concludes Susan Roberts of Tufts University, author of Feeding Your Child for Lifelong Health (Bantam Doubleday Dell, 1999).

   “But until more long-term studies are done, we can’t prescribe one diet that will help all of them.”

1 Pediatrics 58: 154, 1976
2 Pediatrics 61: 818, 1978
3 Pediatrics 83: 7, 1989

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