What Is E100?
E100 is the E-number for curcumin, a natural yellow-orange pigment extracted from turmeric root (Curcuma longa). It's used as a food colouring to give products a warm yellow or golden hue.
Turmeric has been used for thousands of years as a spice, dye, and traditional medicine in South Asian cuisines. The curcumin extract used in food is the same compound that gives curry its distinctive yellow colour.
On a UK label
E100 is a plant-derived colour with an unrestricted ADI under EFSA's 2010 re-evaluation. EFSA, FDA and the FSA carry no current concern flag. Turmeric itself has been a food staple for centuries.
Common Uses of E100 (Curcumin)
You'll find E100 in many UK foods:
- Dairy products: Butter, margarine, cheese (especially processed cheese)
- Baked goods: Cakes, pastries, biscuits
- Sauces and condiments: Mustard, curry sauces, pickles
- Ready meals: Indian and Asian dishes, rice products
- Snacks: Crisps, popcorn, savoury snacks
- Beverages: Some soft drinks and flavoured drinks
What the evidence shows
Regulatory position
E100 is approved in the UK, EU, US and most countries worldwide. In its 2010 re-evaluation EFSA set no numerical ADI for curcumin — the agency concluded the available toxicology did not warrant one. The FDA classifies turmeric and curcumin as approved colour additives. There is no FSA concern flag.
Allergy
Curcumin and turmeric allergy is rare in the published literature. Where reported, it's typically contact dermatitis in people occupationally exposed (curry production, food handlers). Oral reactions to dietary E100 doses are not commonly described.
The supplement-dose evidence (and why it doesn't translate to food doses)
Curcumin has been studied extensively as a supplement at gram-scale doses for anti-inflammatory, antioxidant and joint-health endpoints. Trial evidence is mixed and most reviews note small or inconsistent effects. Crucially, the food-additive use of E100 is at milligram doses — orders of magnitude below the supplement trial range — so neither the supplement evidence base nor its caveats apply meaningfully to a yellow tint in a margarine or curry sauce.
Medication interactions
At supplement-level doses, curcumin can affect anti-coagulant drugs (warfarin), some chemotherapy drugs, and blood-glucose-lowering medications. These interactions are not a meaningful concern at food-colouring doses, but anyone taking high-dose turmeric supplements alongside prescription medication should discuss the combination with a pharmacist or GP.
Practical notes
- Staining — curcumin's strong yellow pigment stains clothing, work surfaces and teeth (the tooth staining is temporary). Worth knowing if you cook with turmeric at home.
- Source — most commercial E100 is extracted from turmeric (Curcuma longa) grown in India and southeast Asia.
E100 vs synthetic yellow dyes
E100 is often used as a plant-derived alternative to synthetic yellow dyes:
- E102 (Tartrazine) — azo dye in the Southampton Six, carries the FSA warning
- E110 (Sunset Yellow) — azo dye in the Southampton Six, carries the FSA warning
E100 carries no equivalent warning.
Reading a UK label
Look for "E100", "Curcumin", or "colour: turmeric" in the ingredient list. Some brands declare both the colour family ("turmeric") and the technical name (curcumin) — same thing.