Diet and disabilities—1
Should we be asserting that dyes are linked to behavior problems?
In a press conference 22 April 2025, Robert F. Kennedy, Jr., US Secretary of Health and Human Services announced an initiative in which the US Food and Drug Administration will encourage removal of synthetic dyes from foods. According to Secretary Kennedy (see press release),
“For too long, some food producers have been feeding Americans petroleum-based chemicals without their knowledge or consent,” said HHS Secretary Robert F. Kennedy, Jr. “These poisonous compounds offer no nutritional benefit and pose real, measurable dangers to our children’s health and development. That era is coming to an end. We’re restoring gold-standard science, applying common sense, and beginning to earn back the public’s trust. And we’re doing it by working with industry to get these toxic dyes out of the foods our families eat every day.”
Here is a 55-min video of the press-conference courtesy of Forbes (via YouTube).
I want to call readers’ attention to another quotation from the FDA press release:
Today, the FDA is asking food companies to substitute petrochemical dyes with natural ingredients for American children as they already do in Europe and Canada,” said FDA Commissioner Marty Makary, MD, MPH. “We have a new epidemic of childhood diabetes, obesity, depression, and ADHD. Given the growing concerns of doctors and parents about the potential role of petroleum-based food dyes, we should not be taking risks and do everything possible to safeguard the health of our children.
Commissioner Makary pretty clearly linked dyes and problems such as diabetes, ADHD, etc. In this statement. I want to express caution about accepting that connection. Although I agree with recommending healthy diets for both children and youths with disabilities (and their families and educators), I am wary about the arguments for some aspects of diets. We have seen many false leads in discussions about diet and disabilities. I fear that some of the publicity about dietary matters will incite new rounds of misinformation, fallacious arguments, and distraction from very important matters (e.g., effective instruction!).
Historical examples
I wrote about concerns with food additives in the 1990s. On a Web site I developed (with assistance from then-doctoral-students Kerry Martin Frymier and Sean Joseph Smith) I discussed a widely discussed diet that removed food additives from children’s diets.
Food Additives
Another popular notion is that food additives, especially artificial colorings and flavorings, cause hyperactive behavior. The idea that food additives cause hyperactivity was championed in the 1960s and 70s by Ben Feingold, who wrote the widely cited book, Why Your Child Is Hyperactive. Feingold argued that salicylic acids in some foods (it occurs naturally in, for example, tomatoes and strawberries) and, especially, food additives caused an allergic reaction that was manifested as hyperactivity.
Based on this assumption, Feingold developed the "Feingold Diet" (also known as the Kaiser-Permanente Diet) in which people ate very carefully controlled foods and avoided other products that might contain salicylates (e.g., toothpaste with artificial colorings). He provided case studies indicating that following the diet reduced hyperactive behavior in children. The diet was very difficult to follow, making it hard to test its effects independently; scientists had to devise equally difficult diets as placebos. However, many careful studies of the effects of the Feingold diet were conducted; they revealed that it did not help reduce hyperactivity. When Ken Kavale and Steve Forness (1983) aggregated all the studies of the Feingold diet done by the early 1980s, they could find few benefits from it. At best, there may be a small subgroup of children for whom it works.
The following figure provides a graphic representation of the effect size for the Feingold diet (data from Kavale & Forness, 1983). Forness et al. (1997) and Lloyd et al. (1998) reported that, in comparison to other special education methods (e.g., curriculum-based measurement, Direct Instruction, mnemonics) the Feingold diet was among the least beneficial—right down there with learning styles.
More recent evidence
To get a more contemporary look at artificial food additives on children’s behavior, I searched for relatively recent reviews. I found lots of reports, many of which provided more opinion than evidence. That is, many read more like position papers than scientific reviews. Here are notes about four reports I found and read; this is not a representative sample of reports.
Ambroziewiz et al. (2024) reported a narrative review (i.e., not a meta-analysis) that led them to argue that there are relationships between artificial food colorants and behavior.
Arnold et al. (2012) noted the flaws common to many studies (“nonstandardized diagnosis, questionable sample selection, imperfect blinding, and nonstandardized outcome measures”) and then they said they believed there were small effects of artificial food colors on behavior. Theirs was a narrative—not a quantitative literature—review.
Conners (2012), who conducted many original studies about food additives and hyperactivity, was skeptical that there was a relationship.
Miller et al. (2022) argued that human clinical trials and animal literature “support an association between synthetic food dyes and behavioral effects observed in children.” I doubt their conclusion for these reasons: (a) they argue cause from correlation data; (b) much of the evidence they evaluate is not from humans; and (c) they did not include dozen of studies that had shown no effects.
Nigg et al. (2011) conducted an integrative review of 24 studies. They concluded that “A restriction diet benefits some children with ADHD. Effects of food colors were notable were but susceptible to publication bias or were derived from small, nongeneralizable samples.”
I was unprepared for the diverse character of the literature that I found. As I remarked, many of the sources were more like opinion papers, even though they said they “reviewed” literature. I thought I might find something more rigorous in scientific data bases of reviews (e.g., Campbell Collaborative), but came up empty. I’m left with the impression that there is little conclusive evidence either way. I hope that a couple of well-respected teams of scientists will weed through the papers that purport to review this literature and conduct a systematic and objective analysis.
So, do food additives cause behavior problems? Well…maybe?
Sources
Ambroziewicz, Z. M., Siemiątkowski, R., Łata, M., Dowgiert, S., Sikorska, M., Kamiński, J., Więcław, K., Grabowska, H., Chruściel, J., & Mąsior, G. (2024). Long-Term Health Effects of Artificially Colored Foods in Adults and Children: A Review of Scientific Literature on Attention Deficits, Carcinogenicity, and Allergy Risks. Journal of Education, Health and Sport, 76, 56522-56522.
Arnold, L. E., Lofthouse, N., & Hurt, E. (2012). Artificial food colors and attention-deficit/hyperactivity symptoms: conclusions to dye for. Neurotherapeutics, 9(3), 599-609.
Forness, S. R., Kavale, K. A., Blum, I. M., & Lloyd, J. W. (1997). What works in special education and related services: Using meta-analysis to guide practice. Teaching Exceptional Children, 29(6), 4-9.
Kavale, K. A., & Forness, S. R. (1983). Hyperactivity and diet treatment: A meta-analysis of the Feingold hypothesis. Journal of Learning Disabilities, 16, 324-330.
Lloyd, J. W., Forness, S. R., & Kavale, K. A. (1998). Some methods are more effective. Intervention in School and Clinic, 33(1), 195-200.
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), 45.
Nigg, J. T., Lewis, K., Edinger, T., & Falk, M. (2012). Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. Journal of the American Academy of Child & Adolescent Psychiatry, 51(1), 86-97.