also: Caramel · Caramel colouring · E150a · E150b
The brown in cola, gravy and soy sauce, made by heating sugar. Two of its four types are made with ammonia and carry by-products flagged in animal studies.
Scan a barcode to check a food for caramel (general). NutraSafe Pro · £6.99/month · iOS
Water, soya sauce extract (23%) (water, soya beans, wheat flour, salt), sugar, salt, distilled cane vinegar, colour (plain caramel), yeast extract powder
The ammonia-made types (E150c and E150d) contain a by-product called THI that lowered white blood cell counts in animal studies, and another, 4-MEI, that caused lung tumours in mice and is classed by IARC as possibly causing cancer.
2,316
of the 43,325 UK supermarket foods we checked declare E150 in their ingredients
That is 5.3%, counted by its code or its name. The count includes every form of E150 (E150a, E150b, E150c, E150d).
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. The ammonia-made types (E150c and E150d) contain a by-product called THI that lowered white blood cell counts in animal studies, and another, 4-MEI, that caused lung tumours in mice and is classed by IARC as possibly causing cancer. E150b and E150d are made with sulphites and may carry traces, which can set off breathing problems in people sensitive to sulphites.
Caramel colour is a dark brown mixture made by heating food sugars such as glucose, fructose or sucrose under controlled conditions. There are four types, depending on what else is added: E150a (plain, nothing added), E150b (made with sulphites), E150c (made with ammonia compounds) and E150d (made with both). The ammonia-made types, E150c and E150d, are the most used commercially.
It colours food and drink anywhere from pale straw to almost black, and in some uses adds a slightly bitter, roasted note. It dissolves in water and spreads evenly through drinks and sauces without changing their texture.
Cola and other dark soft drinks (usually E150d), beer and stout, cider, soy sauce, brown sauce, Worcestershire sauce, gravy, dark bread, biscuits, caramel sweets, breakfast cereals and Scotch whisky (usually E150a). UK labels call it colour (caramel), caramel colour or colour (E150), sometimes with the letter (E150a, E150c, E150d).
4-MEI forms as a by-product when the ammonia types, E150c and E150d, are made. A two-year US government feeding study found clear evidence of lung tumours in male and female mice, though not in rats. Tests for DNA damage were consistently negative, which suggests the tumours only appear above a certain dose. In 2013 IARC classed 4-MEI as possibly causing cancer in humans (Group 2B), based on the animal data, as there are no human studies.
A two-year feeding study found clear evidence of cancer in male and female mice, with more lung tumours. Results in rats were negative or unclear.
IARC classed 4-MEI as possibly causing cancer in humans (Group 2B), based on sufficient animal evidence and no human data.
4-MEI did not damage DNA in bacterial tests or in animal micronucleus tests, which suggests the mouse lung tumours need a threshold dose.
European reviewers concluded the mouse cancer effect of 4-MEI probably has a threshold, because it does not damage DNA, and did not see intake from caramel colours as a concern at current use levels.
The ammonia type E150c contains a minor by-product called THI. Several animal studies found that THI lowers the number of lymphocytes, the white blood cells central to immune defence. The effect depended on the dose and reversed when it stopped. Because of this, European reviewers set a stricter daily limit for E150c than for the other types.
THI lowered lymphocyte counts in mice and rats, more so at higher doses, and the effect reversed when it was stopped.
THI traps circulating T cells in the liver, lungs and kidneys, and suppresses T cell responses in the lab.
Reviewers set a separate daily limit of 100mg per kg of body weight for E150c, against 300mg per kg for the group, because of uncertainty about THI's immune effects in animals and the lack of human data.
E150b and E150d are made with sulphites, and some sulphur dioxide can remain in the finished colour. UK law requires sulphites to be declared on the label above 10mg per kg or per litre of the finished food, whether or not they still do anything. Sulphites can set off asthma-like symptoms and are one of the 14 allergens in UK law.
E150b and E150d are made with sulphites and may carry some sulphur dioxide. The purity rules allow up to 0.2% (2,000ppm) sulphur dioxide in the colour itself.
Sulphur dioxide and sulphites must be declared in UK food above 10mg per kg or per litre in the finished product, whether or not they still have a job in it.
When European reviewers set the limits in 2011, they found toddlers and adults who eat a lot of food coloured with E150c could go over its stricter limit of 100mg per kg. A 2012 estimate using real use levels found intake stayed under the 300mg per kg group limit for everyone, but toddlers could still go over the E150c limit.
Assuming maximum permitted levels, intake of E150c in toddlers and high-intake adults went over its limit of 100mg per kg of body weight.
Using real use levels, no group went over the 300mg per kg group limit, but toddlers could still go over the E150c limit of 100mg per kg.
Daily limit. 300mg per kg of body weight a day for all four types together, and 100mg per kg for E150c on its own because of the THI uncertainty.
People sensitive to sulphites, or whose asthma is set off by them, should look for E150b or E150d and for sulphites or sulphur dioxide in the allergen information. If a label just says colour (caramel) or E150 with no letter and no sulphite declaration, you cannot tell which type it is. No human limit has been set for THI or 4-MEI from caramel colour, so people who want to avoid the ammonia types should look for E150a, the only type made without ammonia or sulphites.
Caramel colour is one of the most eaten colours in the world, in cola, dark beer, sauces and spirits. The label E150 covers four different substances made in different ways, with different by-products. E150a, plain caramel, has the fewest process concerns. The ammonia types, E150c and E150d, are the most used and carry two separate signals: THI, which suppresses immune cells in animals, and 4-MEI, which caused lung tumours in mice. European reviewers concluded the cancer effect has a threshold and that real food intake is below it. California disagreed and requires a warning above 29 micrograms of 4-MEI a day. That is a real scientific disagreement about how the effect works, not just a difference in caution.
No. All four types of caramel colour, E150a to E150d, are approved in the UK and are on the Food Standards Agency's list.
4-MEI is only in E150c and E150d, the ammonia types. IARC classed it as possibly causing cancer in humans (Group 2B) in 2013, based on lung tumours in mice. European reviewers and the US FDA concluded the mouse tumours need a threshold dose and that normal food intake is well below it. California disagreed and requires a warning where a product gives more than 29 micrograms a day. These are different regulatory calls on the same animal data.
Cola and other dark soft drinks (mostly E150d), stout and dark beer (E150c), soy sauce, brown sauce, Worcestershire sauce, gravy, dark bread, some biscuits and cereals, caramel sweets and many blended Scotch whiskies (E150a). Labels call it colour (caramel), caramel colour or colour (E150), sometimes with a letter.
Yes. All four types are made from plant sugars, and the ammonia and sulphite compounds used are minerals, not from animals.
Last reviewed: 20 June 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iOS
