The Last Word: Are Artificial Food Dyes Bad for You?

It’s clear that artificial dyes have no health benefits, but the science around harms is complicated.

While it may be fairly obvious that a bottle of green ketchup (a happily short-lived product) contains artificial dye, most people might be surprised to know that butter’s yellow hue isn’t all-natural either.

Artificial food dyes are in so much of what we eat or drink that we may never give the wild rainbow of colors in the things we consume a second thought. After all, the color additives used in these products have been approved by the U.S. Food and Drug Administration (FDA) and thus are generally considered safe to consume. Nine of the approximately three dozen color additives allowed in our food by the FDA are artificial dyes.

Although a number of major food and beverage manufacturers, including Mars, General Mills, and Kellogg, pledged to remove artificial colors from their products several years ago, none have met that goal. Synthetic food dyes are especially prevalent in products marketed to children; one study found that 43 percent of more than 350 grocery store items contained artificial colors, including nearly all candies (96.3 percent) and fruit-flavored snacks (94 percent), and the majority of drink mixes (89.7 percent).

But the chorus of advocacy groups calling for the removal of artificial dyes from foods is getting louder lately, and they’re citing some very troubling concerns about a broad range of potential health risks, such as allergic reactions, cancer, and neurological problems. Just this month, the advocacy group Consumer Reports called for the removal of Red No. 3 from Peeps marshmallow treats over concerns about potential cancer risks associated with the food coloring.

Are artificial dyes actually harmful to human health? Here is what we know.

Artificial dyes have been used in the U.S. food supply since the 1800s, according to the FDA, and butter and cheese were the first foods allowed to be dyed. The term “artificial” dye or color refers to synthetic petroleum-based chemicals that do not oc­cur in nature. These may be listed on food labels by a specific color and number, for example Yellow No. 6, or sometimes with the term “lake,” as in Blue 1 Lake.

Six artificial food dyes still in use today — Blue No. 1, Blue No. 2, Green No. 3, Red No. 3, Yellow No. 5, and Yellow No. 6 — have been approved for use in our food supply for nearly a century. Much of the current focus of consumer advocates centers on Red No. 3, also known as FD&C and erythrosine. Nearly 3,000 food products currently sold in the United States contain this coloring, including a wide variety of packaged fruits, sauces, sweets, beverages and prepared meals, according to the Environmental Working Group.

In 1990, the FDA banned the use of Red Dye 3 in cosmetics and topical medicines over concerns that the coloring caused cancer in lab rats. But this ban didn’t apply to most foods, including candy and confections, which can still contain Red Dye 3 today. It should have applied to food, too, says Michael Hansen, PhD, a senior scientist for advocacy at Consumer Reports. “The law states that if a food additive or color additive has been shown to cause cancer in animals or humans, then it is not allowed into the food supply,” Dr. Hansen says.

Hansen is referring to the Color Additive Amendments of 1960, legislation that allows the FDA to regulate food dyes and requires that only colors considered “suitable and safe” be used in foods, drugs, cosmetics, and medical devices. This amendment was passed after an incident in the 1950s in which children fell ill after ingesting Halloween candy containing an orange dye. Under this law, the FDA is able to prohibit the use of colorings with a probable risk to consumers, including products linked to cancer in animals or people — but food dyes that were already on the market were allowed to remain in use unless regulators had clear evidence of harms.

European regulators have taken a different approach, reevaluating artificial food dyes already on the market to verify safety and banning these colorants from foods if new studies suggested they had the potential to harm human health. Three dyes that are allowed in the United States carry warning labels in Europe about the potential to cause behavioral and neurological problems in children: Red No. 40, Yellow No. 5, and Yellow No. 6.

“The recent uptick in attention and outcry is likely the result of growing frustration among consumers and advocates alike over FDA’s ongoing and repeated failure to protect us from the harmful chemicals in our foods,” says Thomas Galligan, PhD, a principal scientist for food additives and supplements at the Center for Science in the Public Interest (CSPI), one of the groups leading the charge to get these dyes banned from the food supply.

California lawmakers are currently considering legislation to ban several chemicals and artificial colorings from food. Separately, CSPI late last year urged California lawmakers to add warning labels to foods containing artificial dyes over concerns about neurological and behavioral problems in kids.

Part of the continuing controversy surrounding synthetic food dyes is the fact that research on the effects of these dyes on human health is limited. Many studies are at least 10 years old, and were done on animals (in one case, flies). While there has been no conclusive evidence that food dyes cause cancer, one review found that “all of the nine currently U.S.-approved dyes raise health concerns of varying degrees.” The review goes on to state that Red 3 has been found to cause cancer in animals, and that Red 40, Yellow 5, and Yellow 6 have been found to be contaminated with benzidine or other carcinogens.

Lorne J. Hofseth, PhD, the director of the Center for Colon Cancer Research at the University of South Carolina in Columbia, has studied the effects of synthetic food dyes on colorectal cancer development, and wrote that unpublished data from his team indicates that Allura Red (Red 40) and tartrazine (Yellow 5) can cause DNA damage in colon cells. This research was performed only on cells in a petri dish, however, and research in human subjects is needed.

A review of blue dyes published in November 2021 in Advances in Nutrition stated: “Over the past 100 years, food colors have been found to pose a greater threat to health than any other category of food additives.” While the two mouse studies included in the review found that Blue No. 2 was not carcinogenic, the authors note “a statistically significant increase in two kinds of tumors."

In addition to cancer, another broad concern about food dyes is their potential to cause hyperactivity or other behavioral or neurological issues in children. A report released in April 2021 by the state of California with contributors from the University of California (UC) in Berkeley and UC Davis confirmed a link between the consumption of synthetic food dyes and “adverse neurobehavioral outcomes in some children,” and also found that all of the FDA’s acceptable daily intake levels (ADIs) for synthetic food dyes are based on studies that are 35 to 70 years old.

This is another key part of the controversy over artificial colors: It's difficult to know exactly how much is in your diet. A research review published in May 2019 in Foods stated that “high chronic intake of these additives throughout the entire life is not advisable,” yet there are no guidelines on how to quantify a “high chronic intake,” and the amounts used by manufacturers are usually not listed on product labels. Research published in the June 2017 issue of Food Additives and Contaminants concluded that the average intake of synthetic food colors, even by the consumers who had the most in their diets, still fell well below the acceptable daily intake.

Synthetic food dyes have been linked to a smattering of other health conditions, including allergies and asthma. Recently, a study in mice linked Red No. 40 to inflammatory bowel disease.

While there is little hard evidence that conclusively links the consumption of synthetic food dyes to negative health effects in humans, there is reason to be cautious, particularly for vulnerable populations like children and pregnant women.

The International Association of Color Manufacturers, an industry group, defends the use of artificial dyes. “All color additives allowed for use in the U.S. and the European Union have been extensively studied, which translates into the ability to always assure that colors, enjoyed under their intended use, are safe for the consumer,” the IACM states on its website.

When it comes to behavioral issues in children — the potential food dye risk with the most research to date in people — the FDA’s statement is that “the totality of scientific evidence indicates that most children have no adverse effects when consuming foods containing color additives.”

While FDA stops short of advising parents to limit kids’ exposure to food dyes, its website does mention that people who wish to avoid these chemicals in their food can do so by scrutinizing food labels for any dyes listed among the ingredients.

Because of a lack of research, it’s still unknown whether artificial dyes negatively affect the health of adult humans, and to what degree. Still, artificial food dyes don’t add anything to our diets that we actually need; as the FDA notes, color additives are used only to enhance natural colors of foods and make them more visually enticing.

“These dyes have no nutritional value and are only used to make foods more appealing so you buy them,” Dr. Galligan says.

It's difficult to completely avoid dyes, because they are still in so many products (even those you may not think of, like cheese), and spotting them requires more than scrutinizing product labels at the grocery store and thinking twice about brightly colored foods at restaurants, bakeries, and everywhere else you eat, Galligan adds. “When eating at restaurants where ingredient information is not posted or available, there may be no way to know which foods contain synthetic dyes,” Galligan says.

What you can do, however, is look for organic products, because this certification from the USDA means foods can’t contain colorants made from chemicals. Certified organic foods can use dyes made from things such as carrots or beets, to give foods a brighter hue than they would normally have.

You can also focus your energy on avoiding Red No. 3, the dye with the most clear risk to people, and do your best to limit how much exposure your kids have to artificial food dyes, Hansen advises.

“Given the level of risk, particularly to children, people should consider either limiting consumption of these foods or looking for other foods that don’t have the synthetic food dye,” Hansen says.

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