When Bobby comes home from school bouncing off the walls, his parents could attribute his behavior to a number of factors: pent-up energy, overstimulation, or maybe a behavioral disorder. But is it possible that dyes in the foods he’s eating could be contributing to his rowdiness?

On Wednesday, the U.S. Food and Drug Administration (FDA) will host a public meeting to help determine whether a link exists between artificial coloring and hyperactivity in children.

This theory has been debated by researchers and parents for the past 40 years, but was recently given new credence by a 2007 study from South Hampton, UK, which found that children who consumed a mixture of artificial colors and sodium benzoate (a preservative) displayed higher levels of hyperactivity than those who did not.

The results of this research prompted the Center for Science in the Public Interest (CSPI), the non-profit nutrition watchdog, to petition FDA to ban the synthetic colors at the center of the study.

Over the next two days, the FDA will hear opinions from experts and interested parties on whether existing evidence supports a connection between artificial dyes and hyperactivity. These opinions will inform FDA’s decision on whether or not to restrict the use of these dyes.

Seven synthetic dyes are currently approved by the FDA for use in the United States. These dyes, including “brilliant blue,” (Blue #1) and “fast green” (Green #3), contribute to making many foods recognizable to consumers. They make mint ice cream green and ketchup red.

The use of these dyes is already closely monitored for safety by the FDA, which will make it difficult to prove that they produce harmful effects in children. Before a dye is approved, it must undergo rigorous testing to determine whether it poses any health risks, both short or long-term. Testing can take up to seven years, according to Joe Borzelleca, professor of Pharmacology and Toxicology at Virginia Commonwealth University’s School of Medicine. 

And dyes are not approved universally, but are OK’d in specific amounts for specific products. FDA also monitors dyes closely once they are in use.

“For something like colors that are ubiquitously found in all foods, consumed by people of all ages and healthy and non-healthy situations, our concern level is at the very highest level,” says Borzelleca.  

And so far FDA has not found any evidence of adverse effects from the colors now in use at their approved levels. “Strong and robust data support the safety of many synthetic colors,” Borzelleca says.

Those hoping to prove that synthetic colors are dangerous to children have an uphill battle, not only because synthetic colors are under continuous supervision, but because the body of research proving the connection between these colors and child behavior remains inconclusive.

In Europe, after examining the South Hampton study, the European Food Safety Authority (EFSA) decided not to change its recommendations on food coloring, finding that the study was flawed in its conclusions.

In fact, once the study’s results were adjusted for factors such as socioeconomic status, gender, and education, they showed that 3-year-olds were actually less hyperactive after consuming the mixture, and 8 and 9-year-olds showed greater hyperactivity only at the highest dose, according to Keith Ayoob, director of the nutrition clinic at the Rose F. Kennedy Children’s Evaluation and Rehabilitation Center at Albert Einstein College of Medicine.

Also, because children participating in the study were given a mixture of artificial colors and one preservative, it is impossible to determine from the results which additives caused any change in behavior, Ayoob explains.

Despite EFSA’s rejection of the study, however, the UK’s Food Safety Authority took the precautionary measure of advising manufacturers against using the six dyes given to children in the South Hampton study, and requiring warning labels on products containing these dyes.

In addition to the controversial South Hampton study, other studies are not likely to provide more conclusive back-up for the link between colors and hyperactivity.

“There are several problems with studies on artificial coloring and hyperactivity,” says Ayoob. These problems include bias from parents rating their children’s behavior, the lack of a sufficient wash-out period for dyes to leave children’s systems before the experiment begins, and studies that test only hyperactive or non-hyperactive children.

And, controversial research aside, food scientists and manufacturers will also be reluctant to give up dyes, because the colors make food appealing to consumers, Ayoob says.

Making food recognizable and attractive isn’t only important for selling junk foods like candy, flavored chips and soda. Synthetic colors are also used to dye more healthy foods such as oranges, cheese, soup and margarine.

Why not use natural colors, which have been substituted for manmade colors in many countries in Europe, as well as by some U.S. companies? Artificial colors bind to foods more easily than natural colors, Ayoob says, and the color they provide is more uniform. Natural colors are more expensive to manufacture, which in turn makes the product pricier.

Ayoob, who has worked with hyperactive children for almost 30 years, sees poor diet as a much bigger health threat than food coloring. “If a child has a bad diet that happens to also contain coloring, and you take the coloring out, the child could have an uncolored bad diet,” he says.

“I’d rather look at balancing the child’s diet and getting more of what the child usually tends to need. If I put my effort toward that, I don’t even have to worry about artificial coloring,” he says, “because they’re not going to be eating as much [of it].”