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A gray area over food dyes

The FDA doesn't find enough evidence of a link between the additives and hyperactivity in children. The decision was based on inconsistent studies.

April 11, 2011|By Jill U. Adams, Special to the Los Angeles Times
  • Food dyes are used in many commercial products, including Marshmallow Peeps, popular sweets this time of year.
Food dyes are used in many commercial products, including Marshmallow… (William Thomas Cain, Getty…)

Maraschino cherries, Cheetos, Gatorade and Froot Loops. The rainbow of colors in candies and decorated birthday cakes. The colors of these foods are not from nature — and depending whom you talk to, they are harmless fun or making kids bounce off walls.

Late last month, an advisory panel for the U.S. Food and Drug Administration concluded there was enough evidence to say that foods containing artificial food dyes may trigger hyperactivity in a small percentage of children with behavioral problems such as attention deficit hyperactivity disorder (ADHD) but that there was not enough to say that food dyes cause hyperactivity in the general population. Without clear evidence of harm, the panel voted against recommending warning labels for food products containing artificial colors.

"There's not any convincing data that it's something we need to remove from the diet," says Dr. Wesley Burks, a pediatric allergist at Duke University in Durham, N.C., who served on the FDA panel.

Still, critics of food dyes note that there's no health benefit to having artificial colors in foods, so any risk is unacceptable. "Allowing the use of artificial dyes violates the FDA's mandate to protect consumers from unsafe products," wrote two fierce proponents of an FDA ban — psychiatrist David Schab and consumer advocate Michael Jacobson of the Center for Science in the Public Interest — in a Washington Post opinion article in March.

Here's a look at the science behind the decision and what you can do for your family.

Why are food dyes under review by the FDA, and which dyes are being looked at?

The action was sparked by the Center for Science in the Public Interest, a consumer advocacy group based in Washington, D.C. It petitioned the FDA to conduct the scientific review of artificial colors and specified eight that it feels should be banned or, at a minimum, labeled with a warning: Blue No. 1, Blue No. 2, Green No. 3, Orange B, Red No. 3, Red No. 40, Yellow No. 5 and Yellow No. 6.

What's the evidence that food dyes cause hyperactivity?

Several studies have been conducted to assess whether food dyes (and other food additives) affect behavior in children with ADHD; these were used both by the Center for Science in the Public Interest in its petition to ban the substances and by the FDA panel to conclude that a cause-effect relationship could not be made. Though that may seem puzzling, the fact is that the evidence varies a lot — with some studies showing a large effect and others showing none.

A 2010 paper in the journal Clinical Pediatrics reviewed 10 well-designed studies — ones with a control group and double-blind design, meaning that neither the kids nor the behavior-assessors knew who was ingesting dyes. One report found that only 2 of 22 kids seemed sensitive to food dyes, while another found that 10 out of 10 kids responded.

Another problem is that results differ depending who's doing the assessing: In one study, children's mothers noticed changes in 13 of 36 kids, but teachers noticed changes in only six of those same kids.

One of the most compelling reports, published in the Lancet in 2007, was a study from England that tested a mix of four artificial food colors and a food preservative in 297 preschool- and school-age children — most of whom did not have ADHD. It found increased hyperactivity and inattention in the children who drank a beverage with the mix compared with an additive-free beverage.

"It was quite a large response," says Schab, who is a psychiatrist at Columbia University in New York: He likens it to about one-quarter to one-half of the response one would expect to see if you took a child with ADHD off medication.

But the design of that study made it hard for the advisory committee to draw conclusions about food dyes. Since the researchers used a mix of food dyes, including some that are not approved for use in the U.S., plus sodium benzoate, no single ingredient could be implicated.

The strongest effects of food dyes have been seen in kids with hyperactivity disorders. But even there, notes Burks, multiple factors can contribute to the symptoms of ADHD, such as school environment, genetics and other medical conditions. "There's so many things that exacerbate it, it's hard to show one cause," he says, and that includes food triggers.

Another uncertainty is how food dyes might affect behavior, says Carl Winter, a food toxicologist at UC Davis who also served on the panel. "We don't have a good mechanistic biological understanding of it," he says.

Do food dyes have other risks?

Probably not. Although some of the dyes have caused toxicity, including tumor growth, in animal tests, the amount of dye in such studies is 1,000 times or more higher than humans can feasibly ingest in food.

How much food dye are we eating?

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