E127: Erythrosine

What is E127 (Erythrosine)?

Erythrosine (E127), also known as FD&C Red No. 3 or Cherry Red, is a synthetic cherry-pink iodine-containing xanthene dye used as a food colorant. Unlike most synthetic food dyes which are azo compounds, erythrosine belongs to the xanthene class of dyes. It contains four iodine atoms per molecule, making it unique among food colorings and raising specific thyroid-related health concerns. It has a distinctive cherry-red shade used in certain specific food applications.

Source and Production

Erythrosine is produced synthetically through a specific chemical process:

Base Compound: Fluorescein serves as the starting material 2. Iodination: Four iodine atoms are introduced onto the fluorescein molecule 3. Saponification: The ester is hydrolyzed under alkaline conditions 4. Salt Formation: The disodium salt form is most commonly used in food 5. Purification: Recrystallization produces food-grade quality material

The high iodine content (approximately 58% by weight) distinguishes erythrosine from other food dyes and contributes to its unique biological activity.

Common Uses in Food

E127 is used in relatively limited food applications due to its specific color profile:

Cocktail and maraschino cherries
Canned fruit products
Certain confectionery and sweets
Some cake decorating products
Glacé cherries
Certain medications (tablets and capsules)
Dental disclosing tablets (highlights plaque)
Some red-colored sweets

Health and Safety

Thyroid Effects

The most significant concern with erythrosine is its effect on the thyroid gland. Because the dye contains iodine:

High doses in animal studies caused thyroid follicular cell adenomas (benign tumors)
This led the US FDA to ban erythrosine from cosmetics and externally applied drugs in 1990
The iodine released from erythrosine metabolism can affect thyroid hormone levels
Individuals with thyroid conditions or iodine sensitivity may be particularly at risk

Other Health Concerns

Photosensitivity: Can cause light sensitivity reactions in some people
Neurobehavioral effects: Some early research suggested a link to hyperactivity, though less robustly than the azo dyes
Chromosome effects: In vitro studies showed some genotoxic potential at high concentrations

Regulatory Status

European Union: Permitted as E127, primarily in cocktail cherries and canned cherries in syrup
United States: FDA approved for use in food (FD&C Red 3) but banned from cosmetics and externally applied drugs since 1990 due to carcinogenicity concerns in animals; a delistment process for food use has been slow-moving
ADI: 0.1 mg/kg body weight/day (JECFA) — one of the lower ADIs for food colorings

Identification on Labels

Erythrosine may be listed as:

E127
Erythrosine
FD&C Red No. 3
Red 3
C.I. 45430
Food Red 14

Alternatives

Natural alternatives with similar red/cherry hues:

Cochineal/Carmine (E120): Natural insect-derived red dye
Betanin (E162): Beetroot-derived red
Anthocyanins (E163): Berry-derived red-purple pigments
Cherry/fruit juice concentrates: Natural coloring from fruit itself

Conclusion

E127 (Erythrosine) is a distinctive synthetic food dye notable for its high iodine content and related thyroid concerns. While approved for food use in many jurisdictions, its partial ban in the US (cosmetics and drugs) and its very low ADI reflect caution about its safety profile. Consumers with thyroid disorders, iodine sensitivities, or those following precautionary principles should consider avoiding erythrosine-containing products and choosing naturally colored alternatives.