Yellow Dye 5 vs Perfluorinated Compounds (PFAS): which is worse?

What is Yellow Dye 5?

Yellow Dye 5 (tartrazine) is a synthetic lemon-yellow azo dye derived from petroleum. It produces a bright, stable yellow color in acidic conditions and is one of the most widely used yellow dyes globally. Its chemical formula is C16H9N4Na3O9S2.

What is Perfluorinated Compounds (PFAS)?

Per- and polyfluoroalkyl substances (PFAS) are a large family of synthetic chemicals characterized by extremely strong carbon-fluorine bonds. They are used in food packaging (grease-resistant coatings), non-stick cookware (PTFE/Teflon), food processing equipment, firefighting foam, and many industrial applications. The 'forever chemicals' moniker reflects their extreme environmental persistence.

Documented risks

Yellow Dye 5: Yellow Dye 5 was one of six dyes studied in the landmark 2007 McCann et al. study in The Lancet. The study found statistically significant increases in hyperactivity in children ages 3 and 8–9 given a mixture containing tartrazine and sodium benzoate. EFSA reviewed the evidence and confirmed the effect was real, mandating the EU warning label from 2010. A 2012 review in Neurotherapeutics (Arnold et al.) confirmed that artificial food colors including tartrazine have a small but statistically significant adverse effect on children's behavior that is not confined to those with diagnosed ADHD. Tartrazine is one of the most documented causes of food dye hypersensitivity. Cross-reactivity with aspirin (acetylsalicylic acid, ASA) is well established in allergy literature: individuals with aspirin hypersensitivity have elevated risk of reacting to tartrazine. Symptoms include urticaria, angioedema, rhinitis, and in rare cases anaphylaxis. Prevalence of tartrazine sensitivity is estimated at 0.1% of the population but higher in aspirin-sensitive individuals. Because of this known hypersensitivity risk, the FDA specifically requires Yellow No. 5 to be declared by name on US food labels — an exceptional requirement not applied to most other additives, reflecting the FDA's acknowledgment of this real clinical concern. EFSA's 2009 re-evaluation found no evidence of genotoxicity in standard test systems at food use levels, setting an ADI of 7.5 mg/kg body weight, but noted in vitro evidence at higher doses. In April 2025, the FDA announced plans to phase out Yellow 5 along with other petroleum-based dyes.

Perfluorinated Compounds (PFAS): PFAS are among the most extensively studied and harmful groups of synthetic chemicals in the modern environment. Their unique carbon-fluorine bond stability means they do not break down in the environment or in human body tissues — contributing to bioaccumulation over a lifetime. Health effects documented in human epidemiological studies include: - Cancer: PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid) have been associated with kidney cancer, testicular cancer, thyroid cancer, bladder cancer, and non-Hodgkin lymphoma in occupationally exposed workers and community members with contaminated drinking water. IARC classified PFOA as Group 1 (human carcinogen) in 2023 and PFOS as Group 2B. - Endocrine disruption: PFAS disrupt thyroid hormone signaling and sex hormone balance. Multiple studies find associations between PFAS exposure and hypothyroidism, early puberty in girls, and reduced sperm quality. - Immune suppression: studies have found that PFAS exposure is associated with reduced vaccine response in children and adults, suggesting PFAS may impair immune function. - Developmental effects: prenatal PFAS exposure has been associated with lower birth weight, developmental delays, and reduced immune response in infants. - Cholesterol: PFAS exposure consistently raises LDL cholesterol levels, increasing cardiovascular disease risk. The 2023 EPA MCLG (maximum contaminant level goal) for PFOA and PFOS is zero — reflecting the agency's conclusion that there is no safe level. The EPA set enforceable MCLs in drinking water in 2024. The DuPont/3M PFOA/PFOS contamination of drinking water in communities near Teflon manufacturing facilities led to a $671 million settlement (DuPont/Chemours, 2017) and $10.3 billion 3M settlement (2023) — among the largest environmental contamination settlements in history.