Red Dye 40: How Dangerous is it Really?

Authored by: Emma Robinson

Art by: Kain Wang

Almost everyone can look back on their childhood with a fond memory of eating a giant red sucker or snacking on some bright orange cheetos. However, the growing concern around the quality of the food we eat has led many people to take a harsh look at commonly consumed processed foods. While some aim to cut out preservatives and artificial sugars, one of the most widespread areas of food anxiety is surrounding artificial dyes. 

Natural food dyes have been used since early Egypt, but the first synthetic food dye was not discovered until 1856. As such dyes grew in popularity, the government began to place regulations around their use to mitigate the rise of adverse health effects. Currently, the Food and Drug Administration has a clear list of approved food colors that can be used in production. The FDA monitors the use of food dyes based on their short and long-term health impacts (1). With this in mind, more and more research has been conducted in this field to make sure our foods are not full of colorful poison. The most popular food dye in the foods we consume according to chemical extractions completed on various food categories is red dye 40 (2). With many children consuming high levels of red dye 40, there is concern on its potential impacts for development. 

Specifically, red dye 40 consumption has been shown to increase unfavorable behavior in children (3). In a review that looked at 27 studies of behavior in children, 25 of the studies showed a positive correlation between food dye consumption and bad behavior such as disruptive hyperactivity and lack of focus. Of these 25, thirteen of the studies found this difference in behavior to be statistically significant (3). Studies completed in animal models also suggest an association between food dye consumption and behavioral abnormalities (3). Although there has been a wide range of animal studies, there is still no clear answer to the mechanisms behind how food dye alters behavior. 

Potentially more concerning is the impact of artificial food dyes on more concrete aspects of physical health. Red dye 40 has been shown to contain contaminants that can act as carcinogens (4). Even more alarming is that it is just one of nine food dyes currently FDA-approved that could be cancer-causing (4). Other studies completed in animals also displayed results that could indicate consuming red dye 40 as a risk factor for colorectal cancer. Specifically, mice fed a diet high in red dye 40 and fat showed increased colon inflammation and gut microbiome disturbances (5). Such dysregulation when seen in humans leads to increased risk for developing colon cancer. Another concerning finding was examined in a study on the crustacean Daphnia Magna. This study showed that when placed in petri dishes with increasing concentration of red dye 40, both heart rate and activity level of the crustacean increased (6). This study could provide some insight into how red dye 40 could lead to the hyperactivity seen in humans using a very basic animal model. 

Although there is evidence against the safety of food dyes like red dye 40, there is still not sufficient corroboration to officially ban it from use in foods. While some parents may choose not to feed their children foods containing these dyes, they do bring some extra fun to our childhood treats. With this in mind, the FDA has been making some shifts to promote food industries to shift away from artificial dyes like red dye 40 toward more natural options. With the authorization of four new food dyes earlier this year, companies will hopefully turn to healthier options to get the vibrant colors they seek. Ultimately, this could lead to the FDA’s final goal of red dye 40 being phased out by the end of 2026 (7). The FDA is also making efforts to partner with the National Institutes of Health to pursue further research into how food dyes can impact our health (7). 

Keeping all this information in mind, a reasonable course of action would be to limit artificial food dyes without eliminating them completely. While any synthetic products are likely not optimal for our health, cutting out food dyes entirely is not necessarily realistic in the current climate. However, if the FDA continues to push away from artificial food dyes, then there could be a day in the near future when big-name brands shift to the natural options that are safer for humans to consume. 

References

1. Barrows, J., Lipman, A., & Bailey, C. (2017, November 3). Color Additives History. U.S. Food and Drug Administration. https://www.fda.gov/industry/color-additives/color-additives-history

2. Lehmkuhler, A., Miller, M. D., Bradman, A., Castorina, R., Chen, M.-A., Xie, T., & Mitchell, A. E. (2022). Levels of FD&C certified food dyes in foods commonly consumed by children. Journal of Food Composition and Analysis, 112(112), 104649. https://doi.org/10.1016/j.jfca.2022.104649

3. Miller, M. D., Steinmaus, C., Golub, M. S., Castorina, R., Thilakartne, R., Bradman, A., & Marty, M. A. (2022). Potential impacts of synthetic food dyes on activity and attention in children: a review of the human and animal evidence. Environmental Health, 21(1). https://doi.org/10.1186/s12940-022-00849-9

4. Kobylewski, S., & Jacobson, M. F. (2012). Toxicology of food dyes. International Journal of Occupational and Environmental Health, 18(3), 220–246. PubMed. https://doi.org/10.1179/1077352512Z.00000000034

5. Zhang, Q., Chumanevich, A. A., Nguyen, I., Chumanevich, A. A., Sartawi, N., Hogan, J., Khazan, M., Harris, Q., Massey, B., Chatzistamou, I., Buckhaults, P. J., Banister, C. E., Wirth, M., Hebert, J. R., Murphy, E. A., & Hofseth, L. J. (2023). The synthetic food dye, Red 40, causes DNA damage, causes colonic inflammation, and impacts the microbiome in mice. Toxicology Reports, 11(11), 221–232. https://doi.org/10.1016/j.toxrep.2023.08.006

6. JEI. (2021, July 23). The impact of Red 40 artificial food dye on the heart rate of Daphnia magna | Journal of Emerging Investigators. Emerginginvestigators.org. https://emerginginvestigators.org/articles/20-222

7. FDA. (2025, April 22). HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in Nation’s Food Supply. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/hhs-fda-phase-out-petroleum-based-synthetic-dyes-nations-food-supply