© CBS
An M&M sold in the United States (left) contains food dye that makes it brighter compared to its European counterpart.
Chicago - Is it possible that artificial colors added to our food could be causing behavioral problems in children?

Concerns about synthetic food dyes led many manufacturers in Europe to stop using then. But as CBS 2's Mary Kay Kleist reports, the dyes are used here in everything from cereal to crackers to toothpaste.

Doctors diagnosed Kendall King with Attention Deficit Hyperactivity Disorder, or ADHD, last year and put her on powerful drugs.

But her mother, Kelly King, says, "It just didn't feel right to me."

The Kings heard about a possible connection between food dyes and hyperactivity. Within weeks of taking dyes out of her diet, Kendall no longer needed medication.

"We've had amazing results," Kelly King says. "She's like a whole new child and she's herself again."

Food manufacturers in the U.S. can use nine dyes in all. Red 40, Yellow 5 and Yellow 6 make up 90 percent of the market. You see them everywhere, listed on a bright cereal box or a pickle jar. The colors are used in everything from cough syrup and toothpaste to waffles and crackers.

"They're really ubiquitous in this food supply that we've created," says Dr. David Wallinga of the Institute for Agriculture and Trade Policy.

He says more than two dozen studies point to problems with the dyes. But, do we know if changing a child's diet dramatically improves ADHD?

"The effect is generally very small," Dr. Mark Stein of the University of Illinois says. "It's about a fourth as large as the effect of an ADHD medicine."

The FDA voted against putting warning labels on foods, but it believes more research is still needed. Still, some grocery chains, like Whole Foods, won't sell synthetic dyes.

Warning labels are required in much of Europe. American companies like Kellogg's, General Mills and Kraft did away with the artificial dyes overseas. So, some foods in Europe, like M&M's, just aren't as bright.

Kelly King would like to see the synthetic dyes eliminated in the U.S.

"Our house is just a much calmer place to be," she says.

A statement from the FDA says it does not believe that artificial food dyes cause hyperactivity in children in the general population. However, the FDA says food dyes may exacerbate problems in susceptible children diagnosed with ADHD because they may have a unique intolerance to them.

The FDA is now reassessing safety studies relating to food dyes. Here is the agency's full, unedited statement:
"Based on the data reviewed in the body of scientific literature, FDA last year concluded that a causal relationship between exposure to color additives and hyperactivity in children in the general population has not been established.

However, for certain susceptible children with ADHD and other problem behaviors, the data suggest that their condition may be exacerbated by exposure to a number of substances in food, including, but not limited to, artificial food colors. Findings from relevant clinical trials indicate that the effects on their behavior appear to be due to a unique intolerance to these substances and not to any inherent neurotoxic properties.

FDA's Food Advisory Committee (FAC) (a group of advisors from outside the FDA) met on March 30-31, 2011 to consider available relevant data on the possible association between the consumption of certified color additives in food and adverse behavioral effects in children. The committee was asked to advise FDA as to what action, if any, is warranted to ensure consumer safety from the use of these color additives in food. After receiving information from FDA, experts, and stakeholders, the FAC (1) found that existing data supported FDA's conclusion that there is not an established link between consumption of food dyes and adverse behavioral effects in children, (2) voted against the need for additional information on the product label of foods with color additives, and (3) recommended that additional safety studies be conducted. The FAC also recommended that a rigorous, comprehensive dietary exposure assessment of certified color additives be performed.

FDA currently is collecting data on the levels of color additives used in food. These data will be used to estimate dietary exposure for various populations, including children. Regarding the need for additional safety studies, FDA has begun a reassessment of the numerous safety studies conducted on certified color additives that are available in its files. Based on this evaluation, FDA will determine whether additional safety studies are needed."