How Do Artificial Food Dyes Affect Neurochemistry and Hyperactivity?
- Camryn Hall
- Sep 1
- 4 min read
Artificial food dyes are very common in everyday American foods and drinks. They are typically used to enhance the aesthetic of the product to make it more appealing to customers.
However, studies have found that certain food dyes have negative neurological effects specifically on children. Especially those with attentional problems such as attention-deficit/hyperactivity disorder (ADHD).
What negative effects do the food dyes have?
In human-clinical trials (there were 27 in total), scientists used a method called a double-blind or “challenge” test where kids consumed dye one week and a placebo in another. Sixteen of those trials recorded noticeably worse symptoms in the weeks that they were given dye. In another study (Rowe & Rowe 1964), they used a method called dose-response evidence. They had a group of children drink Yellow 5 at 1 mg. Then, within that same group of kids, they increased the dosage to 2, 5, 10, 20, and 50 mg, with their behavior worsening at each step, showing that even tiny amounts can matter and that the effect grows with each dose. In several animal studies (23 in total), rats and mice that were exposed at a young age (from pre-birth to juvenile) displayed higher spontaneous activity, more learning mistakes, or altered sleep patterns. Brain slices from these animals revealed smaller prefrontal regions and disturbed serotonin or dopamine chemistry.
Some immediate symptoms that were observed by parents and teachers include increased fidgeting, louder vocalizing, more interrupting, shorter work-time, and bedtime trouble after consuming the dye. In the best double-blinded challenge studies, the shift in parent-rated “hyperactivity” averages an effect size (ES) of ≈0.18–0.28—small for any one child but large enough to matter when an entire classroom consumes dyed snacks.
Another symptom caused by artificial food dyes is cognitive drag. Psychometric tests register slower reaction times and reduced sustained-attention scores during the weeks that the children consumed the dye (ES ≈0.27). Toxicologists concluded that the group-average loss of IQ points was ≈3 IQ points.
Food dyes also have physiological side effects that are connected to behavior. According to EEG mapping (aka a qEEG or Quantitative Electroencephalogram, which is a diagnostic tool used to measure electrical activity in the form of brain wave patterns), there is a jump in fronto-temporal β-band power (linked to restless motor activity) within hours of dye intake. One specific dye, Yellow 5 (aka tartrazine or sunset-yellow), can cause a spike in urinary zinc excretion, temporarily lowering serum Zn (an essential cofactor for dopamine metabolism). Mast-cell histamine release has been demonstrated in vitro (which means that it was observed in a controlled, artificial environment outside of a living organism) with this dye as well, further proving the symptom of being “hyperactive”.
What causes these negative effects?
The seven broadly approved U.S. dyes are: Brilliant Blue (FD&C Blue 1), Indigotine
(Blue 2), Fast Green (Green 3), Tartrazine (Yellow 5), Sunset Yellow (Yellow 6),
Erythrosine (Red 3), Allura Red (Red 40). Two niche dyes—Citrus Red 2 (orange skins)
and Orange B (sausage casings). All are synthesized from petroleum
aromatic rings.
Yellow 5 causes zinc chelation, which means that it removes the zinc and excretes it through urine. It also causes immune cells to dump histamine, and kids who carry “slow histamine-clearance” genes (HNMT variants) react more strongly in behavior trials. Animal work shows erythrosine (Red 3) raises corticosterone and alters hepatic enzymes, hinting at broader metabolic stress even outside the brain. In rat studies, maze errors and brain-cell losses caused by weeks of Red 40 or Yellow 5 dosing were cancelled out by antioxidants such as vitamin E or taurine, suggesting that those dyes can cause a lot of free-radical damage in the brain. Also in rat studies, six-week exposures to human-relevant doses of Red 40 or Yellow 5 shrank the medial prefrontal cortex and trimmed neuron branches in rats—exactly the circuitry that regulates attention and impulse control.
Who is affected the most?
Across trials, about 8-12% of children show repeatable, noticeable behavior changes after dye intake. However, the percentage climbs up to 15-30% in diagnosed ADHD groups. Preschoolers to early-grade students exhibit the strongest symptoms. Children with certain histamine-degrading gene types (HNMT Thr105Ile or T939C) or the common dopamine-transporter 10-repeat variant (DAT1) tend to react more, especially around ages 8–10.
In the United States’ top 5% of consumers, it is common to buy food and drink with artificial dye in them, such as neon cereals, sports drinks, and dyed medicines. These people ingest 1-8 mg of dye per kilogram of body weight in a single day. For Red 3, that already bumps into or exceeds the stricter World Health Organization limit.
All in all, there is more research yet to be done on this topic. For now, results show that these commonly consumed dyes have a negative effect on the health and behavior of children and people with ADHD.
Author’s note: This article is dedicated to one of my best friends, Hannah. She was the one that inspired me to write this blog on this topic. She is addicted to Baja Blast, but she says that she can’t drink it because the blue dye in it affects her ADHD. However, she still proceeded to drink 15 over the course of 5 days while we were at church camp this past summer. RIP her unbroken record of 17 from last year.
Sources:
Camryn Hall is a rising senior at Hughesville Jr./Sr. High School in Hughesville, Pennsylvania. She aspires to study Food Science because she appreciates chemistry and how it can relate to her love of food, cooking, and baking. She plans on studying Food Production and Food Chemistry.
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