Yellow Dye 6 vs Potassium Sorbate: which is worse?

What is Yellow Dye 6?

Yellow Dye 6 (Sunset Yellow FCF) is a synthetic orange-yellow azo dye derived from petroleum. It produces a bright orange-yellow color and is structurally similar to Yellow 5 but produces a more orange shade. Its chemical formula is C16H10N2Na2O7S2.

What is Potassium Sorbate?

Potassium sorbate is the potassium salt of sorbic acid, a naturally occurring short-chain fatty acid originally derived from the mountain ash berry (Sorbus aucuparia). Commercial potassium sorbate is synthetically produced by reacting sorbic acid with potassium hydroxide. It is the most widely used food preservative globally.

Documented risks

Yellow Dye 6: Yellow Dye 6 was included in the 2007 Lancet study (McCann et al.), which found that a mixture of six dyes including Yellow 6 and sodium benzoate significantly increased hyperactivity in children. EFSA confirmed the effect warranted mandatory warning labels in the EU. EFSA's 2009 re-evaluation examined animal carcinogenicity data and found some studies showing adrenal tumors in male mice at high doses. EFSA set an ADI of 2.5 mg/kg body weight — lower than Yellow 5's ADI of 7.5 mg/kg, reflecting greater concern. The review noted limitations in the available data. Impurity concerns: commercial batches of Yellow 6 have been found to contain aromatic amine impurities including benzidine and 4-aminobiphenyl — both IARC Group 1 human carcinogens. A 1992 CSPI analysis documented these impurities, citing them as reason for concern. A 2007 study in Toxicological Sciences found Yellow 6 altered zinc and iron biomarker levels in rat blood at high doses, raising mineral metabolism concerns. Human relevance at typical exposure is unclear. Hypersensitivity reactions including urticaria, rhinitis, and contact dermatitis are documented. Cross-reactivity with aspirin is reported similarly to Yellow 5. In April 2025, the FDA announced plans to phase out Yellow 6 with other petroleum-based dyes.

Potassium Sorbate: Potassium sorbate has a generally good safety profile compared to other synthetic preservatives. EFSA's 2015 re-evaluation maintained the ADI at 3 mg/kg body weight, finding no significant carcinogenicity or genotoxicity. However, some human and in vitro studies have documented concerns. A 2010 study in Toxicology in Vitro found potassium sorbate was genotoxic (caused DNA strand breaks) in human blood cells at concentrations achievable in food. The study found it damaged peripheral blood lymphocytes. A 2014 study in Food and Chemical Toxicology found potassium sorbate caused DNA damage in human lymphocytes at food use concentrations. Contact dermatitis and allergic reactions from topical use are documented. At very high doses in animal studies, liver and kidney effects have been observed. The general regulatory consensus is that potassium sorbate is one of the safer food preservatives, but the in vitro genotoxicity findings deserve attention.