Odds are, something in your pantry is colored with petroleum.

Synthetic dyes — which give fruit snacks their bright colors and cereals their rainbow crunch — are embedded into the everyday foods that fill grocery store shelves, often in ways consumers don’t realize. However, concern over their health effects has been growing in recent years, fueled by mounting evidence that certain synthetic dyes may harm children’s long-term health.

A new study shows that the use of these chemicals in the manufacturing of foods and beverages in the U.S. is more widespread than many might expect. Nearly 1 in 5 food items and beverages sold in the U.S. contain synthetic dyes, and many of them are commonly marketed to children.

For many Americans, synthetic dyes such as Red 40 and Yellow 5 have become invisible staples of their diet. These petroleum-derived additives are commonly added to processed food and beverages to increase visual appeal and maintain color consistency. However, emerging research has made it clear that they also increase the risk of a range of adverse neurobehavioral effects — to which children are especially susceptible.

A national study published Tuesday in the Journal of the Academy of Nutrition and Dietetics looked at nearly 40,000 products produced by the top 25 U.S. food and beverage manufacturers, and found that synthetic food dyes were present in 19% of them.

The study also determined that products using synthetic dyes were significantly more likely to be high in added sugars and low in nutritional quality. Even more concerning, researchers found that 28% of the products in categories most commonly marketed to children, including breakfast cereals, candy and sugar-sweetened beverages, contained synthetic dyes.

Although the study focuses on the prevalence of synthetic dyes in U.S. food and beverages, Elizabeth Dunford, a lecturer at the University of New South Wales and co-author of the study, noted that its findings reinforce concerns among parents and public health experts about the potential neurological and behavioral effects of these additives.

A 2021 assessment from the California Office of Environmental Health Hazard Assessment concluded that these additives can “cause or exacerbate neurobehavioral problems in children.” Similarly, a 2022 review found that 52% of studies found a significant association between synthetic dye consumption and adverse behavioral outcomes in children, both those with and without existing behavioral disorders.

These health concerns are not limited to behavioral problems. Red 3, for example, has been shown to cause cancer in laboratory rats, and Yellow 5 has been associated with allergic reactions in some individuals. However, despite decades of concern, current U.S. Food and Drug Administration registrations are still based on studies performed 35 to 50 years ago.

In the recent study, the most common dyes that Dunford and her team found were Red 40, Yellow 5, and Blue 1, appearing in 14%, 11%, and 11% of products, respectively. Synthetic dyes were found in such products as blueberry bagels, guacamole, corn chips and hot dog buns — items that consumers might not expect them. “Even as an educated person, I’ve been tricked,” Dunford said. “Consumers can be misled … when there are all these claims on the front of the pack that say ‘healthy’ or ‘made with real fruit juice,’ but it still has dyes.”

The study found that foods and beverages containing synthetic dyes, on average, had 141% more sugar than dye-free products. The correlation between sugar and synthetic dyes was even more pronounced when it came to products marketed to kids: foods and beverages in the five categories most heavily marketed to children had a mean total sugar content of 42.6 grams per 100 grams — 264% higher than comparable products in other categories.

This marketing strategy, which pairs bright colors with high sugar content, may be part of the reason these foods are so appealing to kids.

But Dunford said that in her personal experience, children won’t notice if they’re given replacement options without those additives. When buying snacks for one of her kid’s parties, she opted for a version of a common brand of corn chips with no synthetic dyes or preservatives. “I gave them to kids at a party, and no one said anything.” Dunford said. “This just goes to show that it’s really the marketing that drives the desire for these products and causes the problems.”

Some steps have been taken to remove synthetic dyes from food and beverages. California banned Red 3 from all foods in 2023 and prohibited six other synthetic food dyes in foods sold in schools in 2024. More recently, in January of this year, the FDA announced that Red 3 will be banned nationwide in all food products by 2027. Warning labels are another potential option to limit synthetic dye consumption, and are being used in the European Union to identify foods containing Red 40, Yellow 5, and Yellow 6.

However, the burden still falls largely on consumers to scrutinize ingredient lists and marketing claims. For many families, that means navigating a colorful and oftentimes misleading food landscape, armed with little more than the fine print on the back of a box.