Caramel Color IV vs Perfluorinated Compounds (PFAS): which is worse?

What is Caramel Color IV?

Caramel Color IV (Class IV caramel, E150d) is a food coloring made by heating sugar with both ammonium and sulfite compounds. This production method creates a unique set of reactive byproducts, notably 4-methylimidazole (4-MEI), which has been linked to cancer in animal studies. It is the most widely used caramel coloring in beverages like Coca-Cola and Pepsi.

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

Caramel Color IV: The primary concern with Caramel Color IV is 4-methylimidazole (4-MEI), a byproduct of the ammonia-sulfite caramel production process. The National Toxicology Program (NTP) found that 4-MEI caused lung cancer in male and female mice at high doses in 2-year bioassay studies, leading to California listing 4-MEI as a known carcinogen under Proposition 65 in 2011. The Prop 65 safe harbor level is 29 micrograms 4-MEI per day (the level that would cause 1 additional cancer per 100,000 people over a 70-year lifetime). CSPI testing in 2011-2012 found Coca-Cola and Pepsi sold in California contained 4-MEI levels that, at typical consumption rates, would exceed this threshold — triggering voluntary reformulation by both companies to reduce 4-MEI in their US products. The FDA reviewed 4-MEI and concluded that typical exposure levels 'are not a safety concern.' EFSA's evaluation found the NTP findings concerning but noted the margin of safety at typical European exposure levels. The cancer mechanism in mice involves high doses that may not extrapolate to typical human cola consumption.

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.