Sulphite ammonia caramel

also: Soft-drink caramel · Acid-proof caramel · Caramel colour Class IV

The dark caramel colour in cola and many brown foods. Making it creates a by-product, 4-MEI, that is rated a possible cause of cancer, so the amount allowed in the colour is capped.

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An ingredient list from the soft drinks and juices aisle

Carbonated Water, Colour (Sulphite Ammonia Caramel), Citric Acid, Flavourings, Sweeteners (Sucralose, Acesulfame K), Preservative (Potassium Sorbate)

E150dColour · Plant

Sulphite ammonia caramel

4-MEI, a by-product formed when this colour is made, is rated a possible cause of cancer because it caused lung tumours in mice.

VeganVegetarian

UK supermarket foods that declare E150d: 396 of the 43,325 we checked (0.9%)

Counted by its code or its name in the ingredient list.

Most of these labels print the code: 77% show “E150d”.

Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted

How common it is in UK food, by aisle

Soft drinks and juices253 products9.6% of 2,627
Sauces, dressings and condiments24 products0.9% of 2,776
Fruit, vegetables and salad21 products0.8% of 2,631
Crisps and savoury snacks14 products0.4% of 3,428

What sulphite ammonia caramel is, what it does and where you will see it

Why it’s worth knowing. 4-MEI, a by-product formed when this colour is made, is rated a possible cause of cancer because it caused lung tumours in mice.

What is it?

Sulphite ammonia caramel is a dark brown food colour made by heating sugars with ammonium and sulphite compounds. It is one of four kinds of caramel colour, and it is the kind used in cola.

What does it do?

It turns food and drink deep brown, and gives cola its colour.

Where you will see it

Cola and many soft drinks, soy sauce, dark beers and some whiskies, gravies, sauces, vinegars and sweets. UK labels call it E150d, colour: sulphite ammonia caramel, or caramel colour.

What the science says

Making it creates 4-MEI, a possible cause of cancer

Making the darker caramel colours (classes III and IV) creates 4-methylimidazole (4-MEI) as an unwanted by-product of the browning reaction. The WHO's cancer agency rates 4-MEI as possibly causing cancer in people, based on lung tumours in mice, which were not seen in rats. EU rules cap how much 4-MEI E150d may contain.

The WHO's cancer agency classes 4-MEI as Group 2B, possibly causing cancer in humans, based on lung tumours in mice.

2013Cancer classificationIARC Monograph 101

4-MEI forms as an unwanted by-product when class III and IV caramel colours are made.

2013Established factIARC Monograph 101

A study of commercial class IV caramel colours found 4-MEI at 112 to 1276mg per kg.

2013Lab studyPLOS One / IARC Monograph 101

A can of cola can go over California's cancer-warning level

California lists 4-MEI under Proposition 65 as a chemical known to cause cancer. A warning is required only when someone takes in more than 29 micrograms of 4-MEI a day. Tests found a 12oz (355ml) can of cola could hold about 130 micrograms, well over that, and several makers changed their caramel colour to lower 4-MEI and stay under the warning level.

California set the warning level for 4-MEI at 29 micrograms a day from February 2012. A Prop 65 warning is needed only above that.

2012State regulatorCA OEHHA Prop 65 (4-MEI findings)

A 12oz can of cola was found to contain about 130 micrograms of 4-MEI.

2012Lab testCA OEHHA

European reviewers set a daily limit and asked for by-products to be capped

European reviewers looked at all four caramel colours in 2011. They set a shared daily limit of 300mg per kg of body weight, with a tighter 100mg for E150c. They asked for the purity rules to cap worrying by-products.

Reviewers set a shared daily limit of 300mg per kg of body weight for caramel colours E150a to d, and a tighter 100mg per kg for E150c.

2011Regulator reviewEFSA ANS Panel re-evaluation of caramel colours (E150a,b,c,d)

Linked to more type 2 diabetes in a large French study

The NutriNet-Santé study followed 108,723 French adults for about 8 years and tracked the colours in the packaged food they ate. People who ate the most sulphite ammonia caramel (E150d) were 30% more likely to develop type 2 diabetes than those who ate little or none. This is one observational study.

Among 108,723 French adults followed from 2009 to 2023, higher intake of sulphite ammonia caramel as a food colour was linked to a 30% higher risk of type 2 diabetes (hazard ratio 1.30).

2026Observational study in peopleNutriNet-Santé cohort, Shah et al., Food Coloring Additives and Incidence of Type 2 Diabetes, Diabetes Care

Where it stands with the regulators

A permitted food colour in Great Britain and the EU

Daily limit. 300mg per kg of body weight a day, shared by E150a, b, c and d (European reviewers, 2011). E150c alone is limited to 100mg.

Legal basis: On the Food Standards Agency's list of approved additives, with purity rules that cap its 4-MEI
Permitted foods: Soft drinks, including colas · Beer and some spirits such as whisky · Soy sauce, sauces, dressings and vinegars · Gravies and gravy browning · Sweets · Other foods, within set limits
Maximum levels: The purity rules cap 4-MEI in E150d at 250mg per kg of colour.
History: European reviewers looked at caramel colours in 2011, set the shared daily limit and recommended capping by-products. California listed 4-MEI under Prop 65 in 2011 and set its 29 microgram warning level from February 2012. Public attention to 4-MEI in cola led several makers to change their caramel colour to lower it.

Who should be careful

People avoiding sulphites should know it is made with sulphite compounds, though the finished colour is not a declared allergen. If you want to limit 4-MEI, the main source is regular cola and other heavily caramel-coloured drinks. Check labels for E150d or caramel colour.

The honest read

4-MEI is rated a possible cause of cancer because of lung tumours in mice, and California requires a warning only when daily intake goes over 29 micrograms. A can of cola can sit above that, which is why many makers cut their 4-MEI. The open question is the by-product, and how much of it you get from drinking cola regularly.

Common questions about sulphite ammonia caramel

Is E150d banned in the UK?

No. E150d is an approved food colour in Great Britain, with a limit on its 4-MEI by-product.

Is the caramel colour in cola a cause of cancer?

Its by-product 4-MEI is rated by the WHO's cancer agency as possibly causing cancer in humans (Group 2B), based on lung tumours in mice. California requires a cancer warning only above 29 micrograms of 4-MEI a day, a level one can of cola can go over.

What foods contain E150d?

Cola and many soft drinks, soy sauce, dark beers and some whiskies, gravies, sauces, vinegars and sweets. Labels call it E150d or caramel colour.

Is E150d vegan?

It is made from sugars heated with ammonium and sulphite compounds, with no animal ingredients, so it is plant-based. Check the finished product if you are strict, as makers vary.