E132 – Indigo carmine | Child behaviour and FDA removal plans

Quick analysis summary about E132 – Indigo carmine food additive

Bottom line about E132

E132 is a synthetic blue food colour also called indigotine. It is graded ORANGE – SOME CONCERNS because toxicology is mostly reassuring, but high-dose animal findings and indirect child-behaviour evidence support caution.

Why this grade for E132

EFSA confirmed the 5 mg/kg body weight ADI in 2023 after a follow-up study did not reproduce earlier testicular effects [1]. A tumour signal occurred only at the highest dose in a long rat study [2,3].

Who may want to limit or avoid E132

Children with reproducible behavioural symptoms after foods containing synthetic colours may limit them under medical guidance. E132-specific oral allergy has not been established.

Common uses and where E132 appears

E132 provides blue or blue-purple colour in sweets, icings, desserts, drinks and decorations where local rules permit it.

E132 source or origin

E132 is synthetic. Industrial indigo is sulfonated to make it water-soluble, then the colour is isolated and purified to food-grade specifications.

Intake note for E132

The ADI (Acceptable Daily Intake) is 5 mg/kg body weight per day. EFSA confirmed this value for qualifying E132 disodium salts meeting revised identity and purity specifications [1].

Is E132 banned anywhere?

E132 remains authorised in selected European Union categories and FD&C Blue No. 2 remains federally listed in the US. FDA is pursuing voluntary industry removal by the end of 2027, while California’s public-school restriction begins on 31 December 2027. Neither is a general food ban.

Safety grading ORANGE – SOME CONCERNS

E132 is not RED because it remains authorised and evaluations do not identify genotoxicity or a demonstrated cancer risk at normal dietary exposure. The ORANGE grade is precautionary, reflecting a high-dose rat tumour signal and indirect neurobehavioural evidence for synthetic dyes as a group.

Study basis or key toxicological reasoning for E132

EFSA’s 2023 follow-up confirmed the ADI after a 56-day dietary study using 88%-pure E132 did not reproduce earlier severe testicular effects [1]. In the 30-month rat study, males received approximately 0, 304, 632 or 1,282 mg/kg body weight per day. Gliomas and malignant mammary tumours increased at the highest dose, while EFSA identified 632 mg/kg body weight per day as the No Observed Adverse Effect Level (NOAEL) and considered a threshold plausible because E132 was not genotoxic [2,3]. The original investigators did not consider the tumour pattern treatment-related, so interpretation remains disputed. A three-generation rat study found no reproductive effects at doses up to 250 mg/kg body weight per day, and developmental studies found no adverse effects in rats or rabbits at doses up to 250 mg/kg body weight per day [4,5]. Human child-behaviour evidence concerns synthetic dyes individually or in mixtures and does not establish an E132-specific effect [6].

Side effects of E132 – Indigo carmine food additive

No expected immediate effect at normal intake. Current evaluations do not identify an expected acute effect from permitted dietary exposure.
Possible behavioural sensitivity. Reviews of synthetic food dyes report that some children may experience increased activity, inattention or restlessness. This evidence does not prove that E132 affects every child [6].
No established oral allergy pattern. EFSA found no reported cases of indigo carmine intolerance or allergy after ingestion. Reactions after intravenous medical use are not equivalent to food exposure [2].
High cumulative exposure. Frequent consumption of several intensely coloured products can increase total dye exposure, although refined EFSA estimates remained below the ADI [2].
Specification dependence. The confirmed ADI applies to E132 material meeting the assessed identity and purity conditions [1].

Should You Avoid E132 – Indigo carmine food additive?

Most consumers do not need to treat occasional E132 exposure as dangerous. People who prefer to minimise synthetic colours can choose uncoloured or naturally coloured alternatives, and children with reproducible behavioural symptoms after coloured foods may benefit from medically supervised dietary assessment. E132-specific oral allergy has not been established. The ORANGE grade reflects precaution around indirect child-behaviour evidence, a high-dose animal finding and current policy changes, not proof that ordinary labelled exposure harms everyone.

Common uses of E132 – Indigo carmine food additive

Blue sweets and confectionery. E132 supplies a strong blue shade.
Icings and cake decorations. The colour supports visual presentation.
Selected drinks and drink mixes. It may be blended with other colours to create purple or green shades.
Frozen desserts and novelty foods. Bright colour improves appearance.
Decorations, coatings and processed foods. Use depends on the applicable food category and jurisdiction.

Common names and synonyms of E132 – Indigo carmine food additive

E132
Indigo carmine
Indigotine
FD&C Blue No. 2
Acid Blue 74
C.I. 73015
Sodium indigotindisulfonate
INS 132

What is E132 – Indigo carmine food additive?

E132, indigo carmine, is a water-soluble synthetic blue colour. Its principal colouring components are sulfonated salts related to indigo. Sulfonation makes the otherwise poorly water-soluble indigo structure suitable for colouring water-based foods. Depending on the specification and jurisdiction, sodium, calcium or potassium salts may be permitted. These salt forms retain the same basic blue colouring function.

Commercial E132 is produced by synthesising and purifying indigo, reacting it with sulfuric acid to introduce sulfonate groups, and then isolating and purifying the resulting colour. The finished additive contains the principal colouring matter together with controlled subsidiary colours, salts and trace impurities.

After oral intake, indigo carmine is poorly absorbed. EFSA found no genotoxicity concern and confirmed the 5 mg/kg body weight ADI in 2023 for disodium salts meeting the revised specifications. Poor absorption and reassuring genotoxicity findings support low concern at normal exposure, while the high-dose rat tumour finding and indirect evidence concerning synthetic dyes in children remain reasons for precaution [1-3,6].

Where is E132 – Indigo carmine food additive allowed (EU vs US)?

In the European Union, E132 is authorised in selected food categories under category-specific maximum levels and combined colour limits. In the United States, FD&C Blue No. 2 remains listed for colouring foods under current good manufacturing practice and every batch requires FDA certification. The FDA is working with industry toward voluntary removal by the end of 2027, while California’s restriction applies only to covered public-school foods and not general retail sales.

E132 – Indigo carmine