Cyanidin
A natural red-purple pigment extracted from berries and red cabbage, used to colour drinks, sweets and dairy products.
What is it?
Cyanidin is an anthocyanidin, the pigment class responsible for the red, purple and blue colours in many fruits and vegetables. It occurs naturally in blackcurrants, elderberries, blackberries, cherries, red cabbage and red apples. As a food additive it is concentrated by maceration or solvent extraction of these plant sources, then used in its glycoside (anthocyanin) form. The colour shifts from red at low pH to violet and blue at higher pH, so it performs best in acidic products. E163a is the sub-code for cyanidin within the broader E163 anthocyanins group.
What does it do?
Cyanidin absorbs light in the green-yellow range, producing the visible red and purple hues. In food manufacturing it replaces or supplements colour lost during heat processing, storage or dilution. Manufacturers may list it as E163a (cyanidin specifically) or simply as E163 (anthocyanins) on the label.
Where you will see it
Soft drinks and fruit-flavoured waters, blackcurrant and berry cordials, jams and fruit preserves, flavoured yoghurts and dairy desserts, ice cream, sweets and chewing gum, and some flavoured breakfast cereals. On UK ingredient labels it appears as anthocyanins, E163 or E163a.
What the science says
Regulatory data gap: no numerical ADI established
When the European Food Safety Authority re-evaluated E163 anthocyanins in 2013, the panel found the toxicological database too limited to set a numerical acceptable daily intake. In particular, there were no long-term toxicity or carcinogenicity studies of the kind normally required. The panel's conclusion was that, because additive exposure is similar to levels naturally consumed from fruit and vegetables, the absence of an ADI was unlikely to signal a real safety problem, but the data gap was formally noted.
EFSA concluded the toxicological database was inadequate to establish a numerical ADI for anthocyanins and identified the absence of long-term toxicity and carcinogenicity studies as a significant data gap.
Short-term animal toxicity studies
A 2024 study testing isolated cyanidin in rats found no adverse effects at any dose tested. No changes in organ weight, blood biochemistry, liver or kidney function, or tissue structure were observed across a 28-day feeding study. The highest dose tested established a no-observed-adverse-effect level, and the researchers called for longer-duration studies to confirm these findings over time.
Oral cyanidin produced no toxicity in rats in acute (single-dose) or 28-day subacute feeding studies. A NOAEL of 30mg/kg/day was established; researchers recommended chronic studies of at least three months.
Cardiovascular effects: observational associations and RCT evidence
Large observational studies have found that people with higher dietary anthocyanin intake have lower rates of heart disease, but diet studies cannot separate anthocyanins from other aspects of fruit-rich diets. Pooled analysis of randomised trials found anthocyanin supplements modestly reduced LDL cholesterol, triglycerides and inflammatory markers in people who already had elevated levels, but the evidence in healthy people was weaker and most trials were small and short.
A meta-analysis of 15 prospective cohort studies (over 554,000 participants) found high anthocyanin intake associated with 17% lower coronary heart disease incidence and 27% lower total cardiovascular disease incidence, though observational studies cannot establish cause.
A meta-analysis of 44 RCTs found purified anthocyanin supplementation significantly reduced LDL cholesterol and triglycerides, with effects most pronounced in participants with elevated baseline values; effects on blood pressure and BMI were not significant.
Bioavailability: low but metabolically active
Cyanidin and its glycosides are absorbed in the stomach and small intestine, but apparent bioavailability measured in blood plasma is low, partly because extensive metabolism in the gut converts them into smaller phenolic acids that may carry some of the biological activity. The gap between strong laboratory results and more modest human data is partly explained by this conversion and by the difficulty of measuring all relevant metabolites.
Bioavailability of cyanidin 3-O-galactoside from food is estimated at approximately 2%, partly because of extensive presystemic metabolism to phenolic acid metabolites; in vitro antioxidant effects do not reliably translate to in vivo outcomes.
Where it stands with the regulators
Who should be careful
No specific group is required to avoid cyanidin at the levels found in food. People taking high-dose anthocyanin supplements alongside warfarin or other anticoagulants should discuss this with their doctor, as laboratory data suggest potential platelet effects at supplement doses; the amounts present as a food colouring are far lower. Look for anthocyanins, E163 or E163a on the label.
The honest read
Cyanidin is one of the most common pigments in everyday fruit and vegetables, and the amounts used as a food colour are within the range of what most people consume naturally from a berry-containing diet. EFSA's 2013 re-evaluation flagged the absence of long-term carcinogenicity studies as a formal data gap, which is why no numerical ADI was set. That gap has not been filled by a comprehensive chronic study since. Short-term animal data and the long history of dietary exposure to cyanidin-rich foods are reassuring, but the long-term picture has not been rigorously tested in isolation from the rest of a diet. The cardiovascular evidence from observational studies is consistent but cannot confirm cause and effect. The gap between strong laboratory antioxidant results and more modest human trial outcomes reflects the compound's low bioavailability and complex gut metabolism. The science is reasonably well-characterised for short-term safety; the long-term picture remains less thoroughly examined than for many synthetic food colours.
Related additives
Common questions
Is E163a banned in the UK?
No. E163a (cyanidin) falls under E163 anthocyanins, which is authorised in the UK under assimilated EU Regulation (EC) No 1333/2008. Its authorisation was retained in UK law after Brexit.
Does cyanidin have any health effects at the amounts used in food?
At the levels used as a food colouring, no specific health effects have been demonstrated. Higher intakes from whole fruit and vegetables have been associated in observational studies with lower rates of heart disease, but these studies reflect overall diet patterns rather than the additive alone. Randomised trials using anthocyanin supplements have shown modest effects on LDL cholesterol in people with elevated levels.
What foods contain E163a?
E163a can appear in soft drinks, blackcurrant and berry cordials, jams and fruit preserves, flavoured yoghurts, ice cream, sweets, chewing gum and some flavoured breakfast cereals. On UK labels it is listed as anthocyanins, E163 or E163a.
Is E163a vegan?
Yes. Cyanidin is extracted from plant sources such as blackcurrants, elderberries, red cabbage and grapes. No animal-derived ingredients are involved.
Sources
- UK FSA Approved Additives and E Numbers - E163 Anthocyanins
- EFSA Panel ANS: Scientific Opinion on the re-evaluation of anthocyanins (E163) as a food additive, EFSA Journal 11(4):3145
- Commission Regulation (EU) No 1129/2011 amending Annex II to Regulation (EC) No 1333/2008 (consolidated Annex II of authorised food additives), EUR-Lex
- Assessment of oral toxicity and safety profile of cyanidin: acute and subacute studies on anthocyanin, PubMed Central PMC11140675
- Anthocyanins, Anthocyanin-Rich Berries, and Cardiovascular Risks: Systematic Review and Meta-Analysis of 44 RCTs and 15 Cohort Studies, PubMed Central PMC8714924
- Cyanidin 3-O-galactoside: A Natural Compound with Multiple Health Benefits, PubMed Central PMC7956414
- NATCOL: Anthocyanins INS 163 / E163 regulatory overview
- International Association of Color Manufacturers: Anthocyanins colour profile
- Wikipedia: Cyanidin
See this on every food you scan
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
Get NutraSafe on the App Store