Are Food Dyes Bad For Your Health?

In September, California became the first state in the nation to ban six artificial food dyes from meals served in public schools.

The move followed a 2021 report from the state’s Office of Environmental Health Hazard Assessment (OEHHA) that concluded the body of evidence supported a relationship between food dye exposure and adverse behavioral outcomes in some kids.

Physicians and researchers said understanding the relationship between food dyes and the potential for disease is an important one, noting that additional research may be warranted.

“As Americans, we have greater exposure to food additives than any other country in the world,” Kathleen Holton, PhD, MPH, of American University in Washington, D.C. who has studied the relationship between food dyes and hyperactivity, told MedPage Today. “It is an uphill battle.”

OEHHA Report

The OEHHA report included 27 clinical trials, several of which were relatively newer. Specifically, it pointed to a trio of double-blinded, placebo-controlled studies that were completed by the same research group in England, published in 2004, 2007, and 2010.

The first of these found that among nearly 300 children with and without hyperactivity in England, there was a general adverse effect of artificial food coloring and benzoate preservatives on hyperactivity that was detectable by parents.

“Based on parent scores, a statistically significant increase in hyperactivity was seen with the dye challenge compared with placebo,” authors of the OEHHA report wrote of the study. “The effect magnitude was >0.2.”

The second study looked at both 3-year-olds (n=153) and 8- and 9-year-olds (n=144), and found that artificial food coloring or a sodium benzoate preservative (or both) in their diet resulted in increased hyperactivity.

For all 3-year-old kids, statistically significant adverse effects were found (effect size 0.20, 95% CI 0.01-0.39), with a greater effect size (0.32) for those who consumed at least 85% of a juice containing a dye dose and had no missing data, OEHHA report authors noted. Statistically significant effects were also seen in 8- and 9-year-old kids who consumed at least 85% of the juice and had no missing data, with effect sizes of 0.12 and 0.17 for two different mixtures tested.

Finally, a third study in the same cohort indicated that certain polymorphisms in histamine degradation genes may mediate the effects of food additives on attention deficit-hyperactivity disorder (ADHD) symptoms.

“These children may represent a particularly susceptible subgroup based on genetic factors and may explain some of the inconsistencies in studies failing to account for this factor,” OEHHA report authors wrote.

Mark Miller, MD, MPM, of OEHHA, who co-authored the report, reiterated the importance of these three trials.

“You are not trying to look at a bunch of kids and another different bunch of kids and compare them,” Miller told MedPage Today. “This is in the same child so that there’s really no question about whether or not the dyes are creating this effect in the children.”

L. Eugene Arnold, MD, of Ohio State University in Columbus, who was not involved in the OEHHA report, also referenced the studies as perhaps the “most impactful research” in this area.

There was a “small, but significant deleterious effect” of a mixture of food dyes on behavior and cognition among children in a designated school district, he noted. This effect was not only in kids with ADHD, and was found to be modified by a genetic cause.

Thomas Galligan, PhD, of the Center for Science in the Public Interest (CSPI), a nonprofit consumer advocacy organization based in Washington, D.C., called the OEHHA report the “best assessment we have had to date.”

“It is primarily based on that human evidence that we have reached this conclusion that food dyes cause behavioral problems in some kids, and that is backed up by the animal evidence and the mechanistic evidence,” Galligan said.

More Research?

On whether more research is warranted, Galligan said he thinks scientists will always say there is interest in more research and getting a better sense of which kids are susceptible and why, so he is not surprised to hear that researchers say that they want to do more. Though he added, “I don’t think we need more research. I think the evidence is crystal clear that food dyes are causing behavioral problems in some kids.”

Meanwhile, there may be challenges to growing the body of work in this area, regardless of where experts stand on the need to do so.

While admitting “much of the research is older,” Holton said challenges for generating new research include difficulty in securing funding and garnering interest from families.

Competing research exists in other food categories (i.e. saturated fat), Holton said. And many parents may be opposed to having their kids withdraw from medication for ADHD, which has “quite a profound effect,” to participate in a study.

There also is the question of ethics, Miller said. “Can you actually do a study where you feed children something that is already proposed to have these effects?” Still, despite the challenges, there would be benefits associated with having more research, he said.

Areas ripe for further data include genetic susceptibility, which “would be valuable, potentially, for families and for clinicians in identifying children that would be at most risk,” he said.

“It would be helpful if we had biomarkers, blood or urine tests of effect and of exposure, so that you could do studies that were more real-time and identify, with these markers, who is affected and at what level of exposure,” Miller added.

Of additional importance are studies looking at “long-term effects of repeated exposures,” and “not just behavioral impacts, but brain development and function,” as well as studies breaking down findings by effects, age, sex, race, and ethnicity, he continued.

“Also, even the most basic stuff really hasn’t been looked at in modern times when we have just a lot more capability,” Miller said. “What happens with pharmacokinetics? “How much is absorbed? How is it metabolized? In children, and I think also examining some of these issues in adults will be beneficial.”

Future Considerations

In 2020, Holton published the findings of a pilot study that focused on artificial food coloring and college students with ADHD.

“We decided to do this study because nobody had really looked at young adults,” Holton said.

The study indicated that exposure to artificial food coloring may affect brainwave activity and ADHD symptoms in college students with ADHD, but larger studies are needed to confirm the findings.

Indeed, additional research pertaining to artificial food dyes may help people to better understand potential health impacts, Arnold said. “It might be that cognitive behavioral effects are kind of the tip of the iceberg. There may be other things going on underneath that are deleterious to health” — including potential carcinogenicity.

In general, Galligan of CSPI said he believes “there is a broad lack of understanding about these behavioral effects of diets in children.”

He added that he would “urge pediatricians, and other healthcare providers, particularly those interacting with children and their families, to really be mindful of the potential impacts that dyes are having.”

One thing to keep in mind is that, though other food additives like preservatives serve an economic and health purpose (i.e. preventing food spoilage and poisoning), artificial food dyes do not provide benefit aside from making food look more attractive, and “in the midst of an obesity crisis,” Arnold said.

Several physicians and researchers pointed to prominent efforts in Europe — specifically in the U.K. — aimed at curbing the use and consumption of food dyes, arguing the same should be able to be done stateside. Many of these dyes can be easily substituted for an organic substitute (i.e. turmeric for a yellow hue).

For individuals who are concerned, Holton recommends avoiding foods that contain artificial dyes, which are easy to identify on food labels with a color and number indicating the dye clearly stated, she said. They can then see for themselves if they notice any behavior changes.

This is something that individuals can do at home “regardless of what legislation decides,” Holton said.