What is it?
Sodium metabisulphite is a mineral salt that releases sulphur dioxide in food, which does the preserving. It is made in a factory, with nothing from animals.
E-numbers / Preservatives / E223
Sodium metabisulphite
also: Sodium metabisulfite · Sodium pyrosulphite · Sodium disulphite
The sulphite most often behind "contains sulphites" on dried fruit, wine and prawns. It can set off asthma, and regulators have been unable to set a daily limit.
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Beef (94%), Rice Flour, Dried Potato, Water, Dried Onion, Sea Salt, Spices, Sugar, Dextrose, Preservative (Sodium Metabisulphite), Salt, Black Pepper.
E223
Sodium metabisulphite
Sulphites set off asthma attacks and breathing problems in sensitive people, particularly those with asthma.
VeganVegetarian
1,106
of the 43,325 UK supermarket foods we checked declare E223 in their ingredients
That is 2.6%, counted by its code or its name.
Only 13% of these labels print “E223”. Most use the name: look for “sodium metabisulphite”.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
How common it is in UK food, by aisle
- Fresh meat, poultry and fish482 products10% of 4,835
- Soft drinks and juices230 products8.8% of 2,627
- Sauces, dressings and condiments79 products2.9% of 2,776
- Cooked and cured meats65 products3.4% of 1,938
What sodium metabisulphite is, what it does and where you will see it
Why it’s worth knowing. Sulphites set off asthma attacks and breathing problems in sensitive people, particularly those with asthma. At high intakes, European reviewers found the gap between real-world intake and doses that affected nerve function in animals was too narrow, and could not set a daily limit.
What does it do?
It releases sulphur dioxide, which stops bacteria, yeasts and moulds growing and blocks the enzymes that turn food brown. It also stops oxygen dulling the colour of dried and processed fruit and slows spoilage in wine and beer.
Where you will see it
Dried apricots and other brightly coloured dried fruit, wine, cider and beer, pickled onions, prawns and other shellfish (to stop the shells going dark), frozen and dried potato products and some baking. UK labels call it sodium metabisulphite, sodium metabisulfite or E223. Sulphur dioxide and sulphites (E220 to E228) must be highlighted above 10mg per kg.
What the science says
Sulphites linked to more cancer in a large French study
In 2026 the NutriNet-Santé study reported that French adults who ate more sulphites, the group that includes sodium metabisulphite, had 12% more cancer overall. These are observational studies: they show links, not proof that the additive causes the disease.
Among 105,260 French adults followed for an average of 7.5 years, higher intake of sulphites as a group was linked to a 12% higher risk of cancer overall.
2026Observational study in peopleHasenböhler et al., The BMJ, NutriNet-Santé cohort
Asthma and breathing reactions
Sulphites release sulphur dioxide gas in the stomach, which can reach the airways and make them tighten, particularly if they are already sensitive. Exactly how is not fully worked out, but it may involve nerve reflexes and chemicals released by immune cells. Under 2% of people overall are thought to be sensitive, rising to 5 to 13% of people with asthma, and more in those with severe or steroid-treated asthma.
Sulphite sensitivity affects fewer than 2% of people overall, rising to 5 to 13% of people with asthma, with those on steroids for asthma most at risk.
2023Clinical guidanceAllergy UK, Sulphites and Airway Symptoms factsheet
Airway tightening from sulphites is thought to involve a nerve reflex, histamine release and other inflammatory chemicals, though the exact mechanism is not resolved.
ObservationalAnaphylaxis UK, Sulphites fact sheet
Sulphite sensitivity has been estimated at about 8.4% of adults on steroids for asthma, and around 20% of children on steroids for asthma.
2012ObservationalGastroenterol Hepatol Bed Bench, Adverse reactions to the sulphite additives, 2012, volume 5, 16-23
A declared allergen, with a threshold
Sulphur dioxide and sulphites are one of the 14 allergens UK law makes labels declare. They must be highlighted in the ingredients whenever the total is above 10mg per kg or per litre as sold. They are the only one of the 14 with an amount below which no declaration is needed.
Sulphur dioxide and sulphites (E220 to E228) are one of the 14 major allergens in UK law and must be highlighted on labels above 10mg per kg or per litre.
LawUK Food Standards Agency, Food allergen labelling technical guidance: the 14 allergens
No daily limit can be set
In 2022 European reviewers followed up gaps left by their 2016 assessment and found makers had not supplied the missing toxicity studies. Using a margin-of-exposure approach based on a nervous system effect in animal tests, they found that high consumers in most age groups had margins below what they consider protective. They withdrew the temporary 2016 limit, saying the data were not enough to set any limit.
Reviewers withdrew the 2016 temporary shared limit of 0.7mg per kg of body weight a day, concluding the toxicity data were not enough to set a limit.
2022Regulator reviewEFSA Journal, Follow-up of the re-evaluation of sulfur dioxide (E220) and sulphites (E221-E228), 2022, volume 20, 7594
Margins of exposure were below 80, the level that signals a safety concern, for high consumers in all age groups except teenagers.
2022Regulator reviewEFSA Journal 2022, volume 20, 7594
The reference point was 38mg per kg of body weight a day, based on a slowed eye-to-brain nerve signal in animal studies.
2022Animal studyEFSA Journal 2022, volume 20, 7594
It breaks down vitamin B1
Sulphites break down thiamine, vitamin B1, lowering the vitamin content of food they preserve. That is why they are not allowed in foods that are an important source of thiamine. How much it matters depends on how much of someone's thiamine comes from sulphite-treated foods.
Sodium bisulphite destroyed thiamine in solution at rates that depended strongly on acidity. At pH 6.5, only 3 to 8% of the thiamine remained after 24 hours at room temperature.
1981Lab studyAmerican Journal of Health-System Pharmacy, Thiamine destruction by sodium bisulfite in infusion solutions
The US FDA notes that sulphites destroy vitamin B1 and are not allowed in foods that are important sources of it.
Regulator guidanceUS FDA, Center for Food Safety and Applied Nutrition
Where it stands with the regulators
Approved in the UK and the EU
Daily limit. None can currently be set. The temporary shared limit of 0.7mg per kg of body weight was withdrawn in 2022 because the toxicity data were not enough.
- Legal basis
- On the Food Standards Agency's approved list for England, Scotland and Wales
- Permitted foods
- Dried fruit · Wine, cider and beer · Prawns and shellfish · Frozen and dried potato products · Pickled vegetables and olives · Jams and marmalades · Some baking · Soft drinks and fruit juices · Breakfast sausages and burger meat with vegetable or cereal
- Maximum levels
- Set for each type of food, from 10mg per kg up to 2,000mg per kg.
- History
- Sulphites have been used as preservatives for centuries. European reviewers set a temporary shared limit in 2016 and flagged gaps in the data. A 2022 follow-up found the missing toxicity data had not been supplied, withdrew the limit and raised a safety concern for high consumers. Sulphites are one of the 14 declarable allergens in UK law, highlighted above 10mg per kg.
Who should be careful
People with asthma, particularly on steroids or with severe asthma, face the highest risk of breathing reactions. People known to be sensitive to sulphites should avoid them. Look for E220 to E228, sulphur dioxide, sulphites or sulphiting agents, highlighted in the ingredients. Our allergen checker reads those terms off the ingredient list we hold for a scanned pack, including sulphiting agents. Check the packet as well.
The honest read
Sulphites raise two separate issues that affect different people. The breathing risk is well established: sulphites set off real asthma attacks in a meaningful minority of people with asthma. The wider population question is less settled. The 2022 European review found high consumers above the level linked to early nervous system effects in animals, but without the studies needed to set a firm limit, reviewers could not set one at all. That does not mean everyone eating dried apricots is at risk: the reference point comes from animal data, and most people eat far less than high consumers. But regulators have flagged a concern they cannot yet put a number on. In 2026 a large French study also linked sulphites as a group to 12% more cancer. It is observational, so it shows a link rather than proof.
Common questions about sodium metabisulphite
Is E223 banned in the UK?
No. Sodium metabisulphite is approved in the UK by the Food Standards Agency.
Can E223 set off an asthma attack?
Yes. Sulphites, including sodium metabisulphite, are a recognised asthma trigger. Under 2% of people overall are sensitive, rising to 5 to 13% of people with asthma, with those on steroids most at risk. Reactions include wheezing, a tight chest, coughing and, rarely, severe airway spasm.
What foods contain E223?
Most often dried apricots and other bright dried fruit, wine, cider, beer, prawns and other shellfish, frozen potato products and some pickles. It must be highlighted on packaged UK food above 10mg per kg.
Is E223 vegan?
Yes. It is a mineral salt made in a factory, with nothing from animals.
Sources
- UK FSA: Authorised Regulated Food Products, E-223 Sodium Metabisulphite
- EFSA Journal 2016;14(4):4438 - Scientific Opinion on the re-evaluation of sulfur dioxide (E220) and sulphites (E221-E228) as food additives
- EFSA Journal 2022;20(12):7594 - Follow-up of the re-evaluation of sulfur dioxide (E220) and sulphites (E221-E228)
- PubMed - Follow-up of the re-evaluation of sulfur dioxide and sulphites (EFSA 2022)
- PMC full text - EFSA 2022 sulphites follow-up review
- Allergy UK: Sulphites and Airway Symptoms factsheet
- Anaphylaxis UK: Sulphites fact sheet
- UK FSA: Food allergen labelling technical guidance: the 14 allergens
- American Journal of Health-System Pharmacy: Thiamine destruction by sodium bisulfite in infusion solutions (1981)
- Food Navigator: Dietary intake of sulfites 'could be a safety concern': EFSA (2022)
- Gastroenterol Hepatol Bed Bench 2012;5(1):16-23 - Adverse reactions to the sulphite additives
- Hasenböhler A et al. (2026) Intake of food additive preservatives and incidence of cancer: results from the NutriNet-Santé prospective cohort, The BMJ
Last reviewed: 20 June 2026
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