While artificial food colorings haven’t been shown to cause ADHD, a link between food dyes and hyperactivity has long been suspected.
Food dyes are commonly used to make food or beverages more attractive, signaling flavor types and fun. Craving cherry taste? It may seem natural to reach for a red (dyed) drink or candy. Bright food colors scream for attention — especially from children.
All European labels on foods containing food coloring offer this warning: “may have an adverse effect on activity and attention in children.” In the United States, foods with these dyes don’t contain this warning on their labels — but should they?
Since the 1970s, researchers, parents, and teachers have suspected a link between food dyes and hyperactivity in young people. Plus, studies have tested a link between food dyes and attention deficit hyperactivity disorder (ADHD), a common neurodevelopmental disorder marked by hyperactivity, impulsivity, and inattention.
Current science suggests that while artificial food colorings (AFCs) don’t cause ADHD, they’re linked to negative neurobehavioral outcomes in the general population.
If you or a loved one have ADHD, you may be particularly interested in finding out how to manage environmental factors that may be affecting ADHD symptoms.
Research on possible negative effects of food dyes began during the 1970s and is still ongoing.
The history of the food dye controversy
In 1973, pediatric allergist Dr. Benjamin Feingold proposed that children’s hyperactivity and learning problems resulted from some foods and food additives. Feingold created a popular diet eliminating AFCs and flavors he believed contributed to hyperactivity.
Researchers post-Feingold have mostly studied the effects of adding or eliminating AFCs to children’s diets.
For example, a 2004 review of 15 double-blind, placebo-controlled trials yielded some evidence that widely used chemicals like AFCs may be neurologically toxic. Trials that screened participants for responsiveness before participation showed the most significant effects, suggesting a need for standardization of participants in future studies.
A 2007 study researched the effects of AFCs in 153 3-year-olds and 144 8-year-olds selected from the general population. Children were put on a 6-week additive-free diet and given a drink each day. Drinks either contained one of two mixtures of food colors and benzoate preservative or a placebo.
In some cases, the children’s hyperactivity significantly increased after they were given drinks containing the test mixtures. Teachers, parents, and outside observers reported on the children’s behavior, and a computerized test assessed the children’s attention.
The study suggested the possibility that AFCs affect the general population. The computerized assessment lent credibility to the results. Some weaknesses in the study made it less than conclusive, including the need for larger sample sizes and more objective assessments (since parents may be biased).
In 2008, the Center for Science in the Public Interest petitioned the Food and Drug Administration (FDA) to take back approvals for eight color additives and asked that warning labels be placed on foods containing these food dyes.
2011 FDA Food Advisory Committee hearing and results
In March 2011, the FDA Food Advisory Committee (FAC) held a hearing on the behavioral effects of AFCs. The meeting focused on ADHD.
- AFCs may have a small but important negative effect on how children behave.
- Children who have nearly enough symptoms to be classified as having ADHD may be pushed over into a clinical diagnosis by a small uptick in symptoms caused by AFCs.
- AFCs do not seem to cause ADHD.
- AFCs do seem to be a possible contributor to adverse effects in attention and hyperactivity in all children.
- AFCs might have small effects on the behavior of individual children, yet when considering the classroom as a whole, individual behaviors add up and the effects might be significant.
Testimony included the need for improvement of future trials, including:
- more systematic exploration of the effects of doses for individual AFCs
- more careful selection of participants, with more controls placed on standardizing what constitutes an ADHD diagnosis
- further exploration into the interactions among AFCs with other AFCs and with nutrients and medications
- more research into indications that AFCs may adversely affect all children, not just those with ADHD
- increased emphasis on larger sample sizes of at least 1,000
The FDA decided that existing data did not show that dyes cause negative behavior in children and that a warning statement was not needed on labels.
Still, the FAC did suggest the need for more research on developmental neurotoxicity and the ways diets expose children to food dyes.
More current research and analysis, 2019–present
In 2019, the California Office of Environmental Hazard Assessment (OEHHA) held a symposium at the request of the California legislature to review and analyze the neurological and behavioral impacts of synthetic food dyes.
A draft report from this symposium underwent peer review in August 2020. In 2021, a comprehensive report and analysis was published.
- A relationship exists between food dye exposure and adverse behavioral outcomes for children in the general population.
- Animal toxicology studies showed changes in brain chemistry and memory in rats given the food dyes Red no. 3, Red no. 40, Yellow no. 5, and Yellow no. 6 over a 6-week period.
- AFC effects may be transient, but the aggregate impact on groups like classrooms is significant over time.
- People in underserved areas without access to good food or nutrition education may be disproportionately affected by AFCs.
- Children have higher exposure to AFCs per pound of body weight.
In the United States, food dyes are regulated by the FDA. In 1906, the Food and Drugs Act prohibited the use of poisonous colors in confectionary and banned food coloring for the purpose of hiding damage.
The United States distinguishes synthetically produced colors from natural ones. AFCs must be tested and certified for safety.
However, on its own, the FDA lacks authority to reassess safety or oversee the mixing of chemicals. Dr. Leo Trasande suggested in his 2020 presentation that this may present a conflict of interest. Granting the FDA dedicated resources and the authority to collect information would remove the conflict.
Since 2010, the European government includes warning labels on foods containing food dyes: “may have an adverse effect on activity and attention in children.” As a result, colors have largely been replaced in Europe to avoid the stigma of the label.
Here are some common AFCs permitted in the United states. The E-number is the dye’s classification number in Europe:
- Blue No. 1, Bright Blue, E133
- Blue No. 2, Royal Blue/Indigo, E132
- Green No. 3, Sea Green Turquoise, E143
- Red No. 3, Cherry Pink, E127
- Red No. 40 Orange Red, E129
- Yellow No. 5, Lemon Yellow, E102
- Yellow No. 6, Orange, INS 110. E110
It may be beneficial to avoid foods containing Red and Yellow food dyes given their adverse effects in animal toxicology.
Since research is still being done on how much dye in your diet is too much, you may choose to be cautious about the dye-containing foods you or your children eat.
Presenter Diana Doell, PhD, review chemist for the Office of Food Additive Safety, FDA offered a summary and analysis of the dietary exposure assessments she and her colleagues did from 2012–2016. These assessments used Food Insight’s database of about 250,000 product labels and dates and their own product label survey in Washington, D.C. grocery stores.
Among the foods containing higher doses of AFCs are:
- soft drinks
- juice drinks
- baking decorations
- breakfast cereals
- frozen dairy desserts
- ice cream cones
- soft candies, gummies
Trasande additionally recommends the following for people with ADHD:
- eating fruits and vegetables that can be peeled
- avoiding processed foods and sugars.
- avoiding plastics with recycling codes 3, 6, and 7.
- eating omega-3s found in fish oil and salmon
In February 2021, the California State Senate Bill requested warning labels on foods in the United States containing AFCs. The bill is slated to be heard in January 2022.
Meanwhile, in his presentation to the OEHHA symposium, Joel Nigg, PhD, director of the Center for ADHD, suggests that those concerned may wish to be cautious about eating food containing AFCs.
If you want more personalized support for your diet related to ADHD, speaking to a health professional may be helpful. The American Psychiatric Association can offer suggestions.
Small changes might have significant benefits to some individuals. So if you feel like you or someone you know seems to be affected by food dyes, reducing foods that contain these dyes may be worth a try.