By Amanda Gardner
November 05, 2010

If your child has attention deficit hyperactivity disorder (ADHD), it's not because he or she played too many video games, logged multiple hours of TV viewing, or ate the wrong kinds of foods. In fact, researchers think the cause of ADHD is largely genetic. But it is tempting to look for dietary factors that could be making symptoms worse.

(View 9 Food Additives That May Affect ADHD as a gallery.)

In particular, a possible link between ADHD and certain foods—including food dyes and preservatives—has been suspected since the 1970s. Still, despite decades of research, experts can't agree on whether eliminating dye-containing foods from a child's diet can ease ADHD symptoms like hyperactivity and impulsivity—except in perhaps a few special cases.

"Scientific evidence is limited to support the association between food additives and ADHD symptoms," says Maida Galvez, MD, MPH, director of the pediatric environmental health specialty unit and assistant professor of preventive medicine and pediatrics at Mount Sinai School of Medicine, in New York City. "Although it is possible that a very small group of children who are allergic to artificial colorings or preservatives may show improvement in symptoms on restriction diets, evidence is insufficient to recommend routine, widespread use of restriction diets to treat a child's ADHD symptoms."

More about ADHD

However, Bernard Weiss, PhD, professor of environmental medicine at the University of Rochester School of Medicine and Dentistry, in New York, says it's clear that food additives can sometimes affect child behavior, at least in the short term. He has conducted controlled trials on the topic and says: "From the standpoint at least of acute effects produced by food color consumption you really can't deny the evidence any more."

For example, a 2007 study published in The Lancet found that a mixture of four artificial food colors plus the preservative sodium benzoate aggravated hyperactivity in two groups of children without ADHD—3-year-olds and 8/9-year-olds. But a second mix didn't have as great an effect on the 8/9-year-olds, even though it also contained sodium benzoate and two of the same colorings, albeit in lower amounts.

Part of the controversy lies in the fact that most food products contain more than one dye or preservative (some candy products have as many as 10 dyes). And most studies have looked at blends of additives, not single ingredients, making it difficult to sort out the culprits.

Next Page: Is only one of them a problem? [ pagebreak ]
"There's no way to know at this point which is the problem dye. Is only one of them a problem? All of them a problem?" says Michael F. Jacobson, PhD, executive director of the Center for Science in the Public Interest (CSPI), which has petitioned the U.S. Food and Drug Administration (FDA) to ban all food dyes because of hyperactivity concerns.

The European Union has already acted to place warning labels on foods containing the six artificial colors in the The Lancet study that "may have an adverse effect on activity and attention in children." Those colors are Yellow No. 5 (tartrazine), Yellow No. 10 (quinoline yellow, not approved in the U.S.), Yellow No. 6 (sunset yellow), Red No. 3 (carmoisine, not approved in the U.S.), Red No. 7 (ponceau 4R, not approved in the U.S.), and Red No. 40 (allura red). Britain's Food Standards Agency (the equivalent of our FDA) is also trying to get companies to phase out these additives.

The bottom line for consumers is that the "jury is still out," says Catherine Ulbricht, PharmD, co-founder of Natural Standard Research Collaboration, which collects data on complementary and alternative medicine, and chief editor of the Journal of Dietary Supplements. "There's inconclusive evidence that food additives actually cause ADHD, but some research suggests that they may be linked to exacerbated symptoms in people who already have ADHD."

Here's a list of food preservatives and colorings that could aggravate attention problems, although none of them (with the exception of Yellow No. 5) have been studied alone in humans. You can also look up the dyes in a number of products at the Institute for Agriculture and Trade Policy website.

Next Page: Preservatives and Colorings [ pagebreak ]
(Click here to view this as a gallery.)

Blue No. 1
Also known as: Brilliant blue
What it is: A food coloring
Where you can find it: Frito-Lay Sun Chips French Onion and other Frito-Lay products; some Yoplait products; some JELL-O dessert products; Fruity Cheerios; Trix; Froot-Loops; Apple Jacks; Quaker CapN Crunchs Crunch Berries; some Pop-Tarts products; some Oscar Mayer Lunchables; Duncan Hines Whipped Frosting Chocolate; Edys ice cream products; Skittles candies; Jolly Ranchers Screaming Sours Soft & Chew Candy; Eclipse gum; Fanta Grape

Blue No. 2
Also known as: Indigotine
What it is: A food coloring
Where you can find it: Froot-Loops; Post Fruity Pebbles; Pop-Tarts products; Duncan Hines Moist Deluxe Strawberry Supreme Premium Cake Mix; Betty Crocker Frosting Rich & Creamy Cherry; M&Ms Milk Chocolate Candies; M&Ms Milk Chocolate Peanut Candies; Wonka Nerds Grape/Strawberry; pet foods

Green No. 3
What it is: A food coloring, though rarely used these days
Where you can find it: Candy, beverages, ice cream, puddings

Orange B
What it is: A food coloring, but no longer used
Where you can find it: Sausage casings

Red No. 3
Also known as: Carmoisine
What it is: A food coloring found in only a few types of food products
Where you can find it: Candy, cake icing, chewing gum

Red No. 40
Also known as: Allura red
What it is: A food coloring and the most widely used food dye in the U.S., trumping both Yellow No. 5 and Yellow No. 6
Where you can find it: Some Frito-Lay products; some Yoplait products; JELL-O Gelatin desserts; Quaker Instant Oatmeal; Trix; Froot-Loops; Apple Jacks; some Pop-Tart products; Kid Cuisine Kung Fu Panda products; Oscar Mayer Lunchables products; Hostess Twinkies; some Pillsbury rolls and frostings; some Betty Crocker and Duncan Hines frostings; some Edys ice creams and candies; Popsicle Sugar-Free Life Savers; some M&Ms and Skittles candies; Nestles Butterfinger; Twizzlers Strawberry Candy; Sunkist Orange Soda; Dr. Pepper sodas; Propel Invigorating Water, Berry & Citrus; Gatorade Orange Thirst Quencher; Fanta Orange

Sodium benzoate
What it is: A food preservative
Where you can find it: Fruit juice, carbonated beverages, and pickles. Youll find it in abundance in acidic foods. It is used to stymie the growth of microorganisms, according to the Center for Science in the Public Interest (CSPI).

Yellow No. 5
Also known as: Tartrazine
What it is: Yellow No. 5 is the only food dye that has been tested alone and not simply as part of a mix. Those studies did link it to hyperactivity. It is the second most commonly used dye in the U.S.
Where you can find it: Nabisco Cheese Nips Four Cheese; Frito-Lay Sun Chips Harvest Cheddar and other Frito-Lay products; some Hunts Snack Pack Pudding products; Lucky Charms; Eggo waffles and other waffle products; some Pop-Tarts products; various Kraft macaroni and cheese products; Betty Crocker Hamburger Helper and other products; some Oscar Mayer Lunchables products; Hot Pockets Ham & Cheese; some Hostess cup cakes; some Betty Crocker frostings; some M&Ms and Skittles products; some Gatorade products

Yellow No. 6
Also known as: Sunset yellow
What it is: The third most widely used food dye in the U.S.
Where you can find it: Frito-Lay Cheetos Flamin Hot Crunchy and other Frito-Lay products; Betty Crocker Fruit Roll-ups; some JELL-O gelatin desserts and instant puddings; Fruity Cheerios; Trix; some Eggo waffle products; some Kid Cuisine Kung Fu Panda products; some Kraft macaroni and cheese dinners; some Betty Crocker frostings; some M&Ms and Skittles candies; Sunkist Orange Soda; Fanta Orange