Experts bust the sugar-hyperactivity myth and other misconceptions about food and children's behavior.

By Jennifer Warner

WebMD Feature

Reviewed By Michael Smith

Any parent that has ever witnessed the aftermath of a child's birthday party has probably blamed sugar for the mayhem that followed the cake and ice cream. But the fact is that sugar may actually be an innocent victim of guilt by association.

Experts say the notion that sugar causes children to become hyperactive is by far the most popular example of how people believe food can affect behavior, especially among young children.

However, despite years of debate and research on the relationship between food and behavior, no major studies have been able to provide any clear scientific evidence to back up those claims.

"The biggest myth of all is that food has any connection to behavior," says Steven Pliszka, MD, professor of psychiatry, University of Texas Health Science Center at San Antonio.

Wesley Burks, MD, professor and chief of pediatric allergy and immunology at Duke University Medical Center, agrees. He says, "There haven't been any good scientific studies that show that there is an adverse effect on a child or adult's behavior chronically with the ingestion of foods."

Busting the Sugar-Hyperactivity Myth

Experts say some of the most convincing evidence against the link between food and behavior is on busting the sugar-hyperactivity myth.

"There is elegant research demonstrating that sugar is not at all related to inattention or hyperactivity," says Mina Dulcan, MD, head of child and adolescent psychiatry at Children's Memorial Hospital in Chicago.

Dulcan and Pliszka point to studies that have shown no effect of sugar on the behavior of children whose parents are convinced that the food makes them more hyperactive. But if the parents think their child has had sugar, they often perceive a difference in behavior that is not really there by objective measures.

Instead, psychiatrists say it's the context of parties, holidays, and other special occasions in which children get their biggest doses of sugar that is often responsible for behavior changes.

Dulcan says part of the reason the sugar-hyperactivity myth has persisted is because people often confuse proximity with causality when it comes to food and behavior. When parents observe a change in behavior, their minds often go back to the child's last treat rather than other circumstances that might have influenced the behavior.

Experts say most children get too much sugar in their diets anyway, but cutting back on sugar is no substitute for addressing other issues that affect behavior. If the child's behavior is disrupting family life or affecting their performance in school, it may be a symptom of bigger problem, such as a conduct disorder or attention deficit-hyperactivity disorder (ADHD), and should be evaluated by a mental health professional.

"It won't hurt anybody to limit their sugar," says Dulcan. "But it won't help their behavior."

History of the Food-Hyperactivity Debate

The idea that food might have an effect on children's behavior first became popularized in the 1970s by Benjamin Feingold, MD, an allergist who published the Feingold diet. He advocated a diet free of more than 300 food additives and naturally occurring salicylates found in plants and many fruits and vegetables to treat hyperactivity.

Since then, many studies have looked at the issue of food additives and hyperactivity, but most have failed to substantiate Feingold's claims or have shown only a mild benefit in a small number of children with ADHD.

"Good research shows that if you follow that diet, perhaps 5% of young kids with ADHD got a little bit better," Dulcan tells WebMD. "But the problem with the Feingold diet is you can't keep a child on it because it eliminates things kids really like."

In addition, a consensus panel convened by the National Institutes of Health concluded in 1982 that there was no scientific evidence to support the claim that colorings or other food additives cause hyperactivity.

But more than two decades later, a new study is now raising the issue again.

British researchers found removing food additives from the diet of a group of 3-year-olds caused a reduction in the children's hyperactive behavior reported by their parents. And when the food colorings and preservatives were added back into the children's diets, the parents reported an increase in hyperactivity.

However, although the parents reported significant changes in hyperactive behavior, the study showed no significant differences on clinical tests of hyperactivity related to the food additives.

"In the absence of the objective tests showing any effect, we have to be slightly dubious about that magnitude of that effect," researcher John Warner, MD, professor of child health at the University of Southampton tells WebMD.

Other experts say this is only one very preliminary study to suggest an association between particular artificial additives and behavior, and it needs to be confirmed by further studies before drawing any firm conclusions.

"When we talk of hyperactivity in terms of behavior, we are looking at a very complex scenario," says Pramod Kelkar, MD, of Allergy and Asthma Care of Indiana, in Indianapolis. "Ascribing hyperactivity to purely diet or purely certain food ingredients seems too simplistic. There are other factors involved, and this may just be part of the puzzle."

Food Allergy Fact and Fiction

Researchers say another popular myth is that food allergies are somehow responsible for behavioral changes or ADHD in children.

"There is absolutely no evidence that food allergies have anything to do with ADHD," says Dulcan. "If you do have food allergy and have hives, or you're wheezing or you can't sleep very well at night, then you're probably not going to do very well in school but that is a separate issue, it's not ADHD."

Studies show food allergies are actually relatively rare and only about 6% of children and 1%-2% have a food allergy, although about 25% of people think they have one.

Babies and young children are most often allergic to:

Peanuts

Milk

Eggs

Wheat

Soybean products

The most common food allergy triggers among older children and adults are:

Peanuts

Tree nuts (such as walnuts, almonds, and cashews)

Fish

Shellfish

Symptoms of food allergies include skin, gastrointestinal, and respiratory symptoms, including hives, itchy skin or rash, vomiting, abdominal pain, diarrhea, coughing, and wheezing.

Those symptoms may cause a child to not feel well or disturb their sleep, which may indirectly affect their behavior. But allergic responses do not directly affect the nervous system or the brain that is responsible for controlling behavior.

Burks says many parents complain that they think their child is allergic to sugar or chocolate, but in order for it to be a real allergy, the immune system should respond in the same way each and every time the child is exposed to the potential allergen -- not just sometimes. The only way to know for sure if a child has a food allergy is to see a doctor for a skin or blood allergy test.

All in all, researchers say that limiting the amount of sugar or artificial additives people or their children eat certainly isn't harmful as long as their nutritional needs are being met. But it's unrealistic to think that food is the cause of behavioral problems.

"The bottom line is that too much artificial food stuff isn't good for you, but I don't think you can believe that it's going to hurt your child's behavior or learning very much," says Dulcan.

Published May 28, 2004.