Amaranth
A synthetic dark-red azo dye used to colour aperitif drinks and fish roe. Banned in the US since 1976; permitted in the UK and EU for a narrow list of products.
Animal studies found kidney calcification and reproductive effects at higher doses, which led regulators to significantly cut the acceptable daily intake. Heavy regular consumers of aperitif wines containing this dye at maximum permitted levels may exceed that limit.
What is it?
Amaranth is a synthetic azo dye producing a deep reddish-purple colour. Despite sharing a name with the amaranth plant, it is entirely petrochemical in origin and has no connection to it. Its chemical name is trisodium (4E)-3-oxo-4-[(4-sulfonatonaphthalen-1-yl)hydrazinylidene]naphthalene-2,7-disulfonate. It is also known as FD&C Red No. 2 in older US nomenclature and CI Food Red 9.
What does it do?
Like other azo dyes, Amaranth absorbs light in the orange-yellow range and reflects deep red and purple wavelengths, giving food a rich crimson colour. It is water-soluble and stable across a range of food processing conditions. In the gut, intestinal bacteria break down the azo bond (-N=N-) through reductive cleavage, releasing aromatic amine metabolites including naphthionic acid derivatives.
Where you will see it
Its use in the UK and EU is restricted to aperitif and spirit drinks (including certain vermouth-based cocktails and aromatised wines) and fish roe products such as lumpfish roe. It is extremely unlikely to appear in everyday packaged food. On a UK label it will read 'Amaranth' or 'E123'.
What the science says
Kidney effects drove the EU safety review
A two-year rat feeding study found that female rats at all tested doses showed increased kidney calcification and pelvic epithelial changes. EFSA's 2010 panel concluded the dose previously treated as a no-adverse-effect level should actually be classified as a low observed-adverse-effect level, which is why the acceptable daily intake was cut to roughly a third of the previous figure. The findings were in animals at doses well above likely human intake from food use.
A 2-year rat study found renal calcification and pelvic epithelial hyperplasia with degenerative changes in females at all dose levels tested. EFSA reclassified the prior no-adverse-effect level as a low observed-adverse-effect level, leading to a lower ADI.
EFSA established an ADI of 0.15 mg/kg body weight per day, significantly lower than the previous Scientific Committee on Food figure of 0.8 mg/kg bw/day and the JECFA figure of 0.5 mg/kg bw/day.
Reproductive and developmental toxicity signals
Several studies in mice, rats, rabbits, cats and dogs contributed to setting the acceptable daily intake. Although the panel noted methodological weaknesses in some studies, they were collectively considered sufficient to establish no-adverse-effect levels across multiple species. These findings, taken together with the kidney data, defined the safety threshold that regulators now use.
Reproductive and developmental toxicity studies across multiple species (mouse, rat, rabbit, cat, dog) contributed to setting the ADI alongside the 2-year kidney study. The combined dataset shifted the point of departure to 15 mg/kg bw/day.
Carcinogenicity: US ban versus EU assessment
The FDA banned Amaranth in 1976 after a Soviet study reported tumour formation in rats and the FDA's own tests were inconclusive. Under the Delaney clause, which prohibited chemicals where cancer risk could not be ruled out, the FDA delisted it. EFSA's 2010 re-evaluation reviewed all available data and concluded Amaranth is neither genotoxic nor carcinogenic. The US ban reflects a 1970s regulatory standard rather than a finding of proven human carcinogenicity.
The FDA terminated certification of FD&C Red No. 2 in February 1976 after inconclusive tests on carcinogenicity in female rats at high doses, applying the Delaney anticancer clause which prohibited use when cancer risk could not be excluded.
EFSA's ANS Panel concluded that Amaranth is not genotoxic and not carcinogenic based on review of all available toxicological data.
Gut breakdown and aromatic amine metabolites
Azo dyes including Amaranth are broken down by gut bacteria into aromatic amine compounds. Research shows Amaranth is reduced by more bacterial species than other common azo food dyes. The toxicological significance of its specific metabolites in humans at food-use doses has not been fully characterised. This is a general concern for the azo dye class, and Amaranth's gut metabolism received less individual study than some other members of the group.
Among four food azo dyes tested, Amaranth was reduced by the highest number of bacterial species in the human gut microbiome, releasing aromatic amine metabolites via reductive cleavage of the azo bond.
Azo dye metabolites produced by intestinal microorganisms include compounds with potential toxicological activity. The review notes that parent dyes classified as acceptable may generate different breakdown products in the human gut environment.
Heavy aperitif drinkers may exceed the ADI
EFSA's 2013 refined exposure assessment found that the average person consuming food and drinks containing Amaranth at permitted levels stays well within the ADI. However, adults who regularly drink large amounts of vermouth-based aperitifs and aromatised wines at the maximum permitted colour concentration could exceed the ADI by around six times. Children's exposure from permitted products was estimated to be about 30 times below the ADI.
Adults who regularly consume high amounts of Americano cocktails and aperitif wines containing Amaranth at maximum permitted levels could exceed the ADI approximately 6-fold. Mean adult exposure from all sources remained below the ADI.
Allergic reactions in sensitive individuals
As with other azo dyes, Amaranth can trigger reactions in people who are sensitive to azo compounds, particularly those with aspirin intolerance or asthma. Reported reactions include urticaria (hives), skin rash, and in some cases worsening of asthma symptoms. The number of documented cases in the literature is small, and this cross-reactivity is a recognised class property of azo dyes rather than unique to Amaranth.
Azo dye sensitivity, including reactions to Amaranth, can manifest as urticaria, angioedema, and asthma-like symptoms, particularly in individuals with aspirin intolerance. Only a limited number of intolerance reactions to Amaranth specifically have been reported.
Where it stands with the regulators
Who should be careful
People with known azo dye sensitivity, aspirin intolerance, or asthma-related conditions may react to this dye. On a label it appears as 'Amaranth' or 'E123', typically in aperitif drinks and fish roe products.
The honest read
The scientific picture on Amaranth is genuinely divided between jurisdictions. The US banned it in 1976 based on inconclusive animal data and a regulatory principle that uncertainty about cancer risk was itself grounds for prohibition. The EU and UK continued to permit it, and EFSA's 2010 review concluded it is not carcinogenic or genotoxic. However, EFSA also substantially lowered the acceptable daily intake because animal studies showed kidney and reproductive effects at doses that earlier regulators had treated as having no adverse effects. The discrepancy between the US ban and EU approval reflects different regulatory frameworks and different thresholds for precautionary action, not a resolved scientific question. The restriction to only aperitif drinks and fish roe reflects how uncomfortable regulators remain with wider use. Studies on gut bacteria breaking down azo dyes into aromatic amine metabolites add a layer of complexity that existing safety assessments did not fully explore.
Related additives
Common questions
Is E123 banned in the UK?
No. E123 Amaranth is approved in the UK and EU but is restricted to a very small number of products: aperitif and aromatised wines and fish roe. It was banned in the United States in 1976 as FD&C Red No. 2. Several other countries outside the EU and UK do not permit it, though specific jurisdictional bans should be verified with the relevant national food authority.
Why did the US ban Amaranth if the EU still allows it?
The FDA banned it in 1976 under the Delaney clause, which prohibited food chemicals where the risk of cancer could not be ruled out. The FDA's own tests were inconclusive after a Soviet study reported tumours in rats. EFSA reviewed the full evidence base in 2010 and concluded Amaranth is not carcinogenic, but still significantly lowered the acceptable daily intake because of kidney and reproductive effects in animal studies. The two positions reflect different regulatory principles rather than different underlying science.
What foods contain E123?
In the UK and EU, E123 is only permitted in aperitif and spirit drinks (such as vermouth-based cocktails and aromatised wines) and fish roe products such as lumpfish roe. It is not permitted in most packaged foods.
Is E123 vegan?
E123 Amaranth is a synthetic petrochemical dye with no animal-derived ingredients. It is considered vegan in itself, though it may appear in fish roe products which are not vegan.
Sources
- EFSA Scientific Opinion on the re-evaluation of Amaranth (E 123) as a food additive, EFSA Journal 2010;8(7):1649
- EFSA Refined exposure assessment for Amaranth (E 123), EFSA Journal 2013;11(10):3442
- UK FSA Approved additives and E numbers
- EU Regulation (EC) No 1333/2008 on food additives, Annex II (UK legislation.gov.uk version)
- FDA CPG Sec 587.200 Uncertified or Delisted Colors in Foods for Export (FD&C Red No. 2)
- EFSA lowers amaranth ADI and questions standards, FoodNavigator 2010
- Metabolism of azo food dyes by bacterial members of the human gut microbiome, Food and Chemical Toxicology 2023
- Toxicological significance of azo dye metabolism by human intestinal microbiota, PMC5870118
- The Truth About Red Dye No. 2, Live Science
- Telford Council - Colours in food: food and drink warnings (Southampton Six list)
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