Polysorbate 80 vs Yellow Dye 5: which is worse?

What is Polysorbate 80?

Polysorbate 80 (Tween 80) is a synthetic nonionic surfactant and emulsifier derived from sorbitol and oleic acid (from vegetable oils) through ethoxylation. It is widely used in food to keep water-based and oil-based ingredients uniformly mixed. Chemical formula: polyoxyethylene (20) sorbitan monooleate.

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.

Documented risks

Polysorbate 80: Emerging research has raised concerns about polysorbate 80's effects on the gut. A landmark 2015 study in Nature (Chassaing et al.) found that dietary polysorbate 80 and polysorbate 60 at concentrations approaching food use levels promoted colitis and metabolic syndrome in genetically susceptible mice by disrupting the intestinal mucus layer and altering gut microbiome composition. The emulsifiers thinned the protective mucus layer, allowing bacteria to come into closer contact with gut epithelial cells and triggering inflammation. This study was a seminal contribution to gut health research, though it was conducted in mice and requires confirmation in humans. A 2020 follow-up study found that dietary emulsifiers including polysorbate 80 promoted gut inflammation and altered gut microbiome in human participants with Crohn's disease. People with inflammatory bowel disease may be most vulnerable to polysorbate 80's potential gut effects.

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.