Hyperactive behaviors in children improve immediately after removing artificial food dyes from their diet. This paper reviews dozens of human and animal studies linking food dyes with behavioral and brain changes. The paper expresses heightened concern regarding blue food dyes as they are the only dye able to cross the brain's protective Blood Brain Barrier.
ABSTRACT
Attention Deficit Hyperactivity Disorder, also known as ADHD, is a neurodevelopmental disorder diagnosed in children. The exact cause of ADHD is not known, but, along with genetic factors, it is possible that environmental factors including toxins and diet may affect symptom severity. Of these dietary components, artificial food coloring (AFC), while approved by the Food and Drug Administration (FDA), has been suspected to be associated with ADHD symptoms. Of the nine FDA-certified food colors, two are used for artificial blue coloring: Blue No. 1 and Blue No. 2. There is limited literature describing the possible role of blue AFC in causing symptoms of ADHD in children. This paper provides a review of the literature surrounding artificial food coloring and its ability to affect the neurodevelopment of children in a way that could increase the behavioral indicators of ADHD. To do this, search criteria were established using a combination of MeSH terms about blue AFCs and ADHD and were entered into PubMed, along with limits on article types and publication dates from January 2000 to June 2022. There was a total of 20 articles that met this search criterion. These articles were reviewed by authors, and the ones not relevant to the topic were excluded. In total, four studies were chosen to be included in this article. After reviewing the literature, it was found that restriction diets, specifically those excluding AFCs, may affect symptom severity. The source of these changes is not known, but possible mechanisms include AFCs causing nutritional deficiencies and allergic reactions or altering neurotransmitter levels. More research is necessary to describe the neurotoxicity of artificial blue dyes in humans.
CONCLUSION
The studies that were reviewed in this article show that diet, especially consumption of artificial food coloring, produces statistically significant increases in ADHD symptoms in children. The mechanism for how AFCs cause such neurological and behavioral changes is not definitively known, but there are a few possible explanations. These include some well-studied hypotheses for the mechanism of ADHD that AFCs could contribute to, such as the dopamine hypothesis, but some less-studied causes like nutritional deficiencies and histamine release may also be possible. While several studies examine the effect of a combination of AFCs on ADHD symptoms in children, there is very little research done on just Blue No. 1 or Blue No. 2 in children. This is illustrated by the low number of studies reviewed in the article after the PubMed search on blue AFC and ADHD, limiting the strength of the conclusions that can be made from the results. In mice and rats, Blue No. 1 specifically has been found to affect neurodevelopment and hyperactive behavior, while Blue No. 2 has not been shown to have any definitive toxicity. There is a need for more research to determine how these individual compounds affect humans, especially because of the ability for Blue #1 to cross the blood-brain barrier. Understanding how artificial blue food dyes affect the brain and behavior of humans through increased research on the topic could provide alternative treatment options for children with ADHD.