Last reviewed: 7 May 2026
The UK label-reader's guide to E220–E228 and the asthma trigger
E220 is sulphur dioxide (SO₂), the parent member of a family of eight UK food additives — E220 through E228 — collectively called sulphites or sulphiting agents. They all release the same active species, SO₂, when dissolved in food or drink, and they are regulated as one group. Under retained UK law (Annex II of Regulation (EU) No 1169/2011), any food or drink containing sulphur dioxide and sulphites at concentrations above 10 mg/kg or 10 mg/L (expressed as SO₂) must declare them on the label as a mandatory allergen — typographically emphasised in the ingredients list, usually in bold. The Food Standards Agency lists sulphites among the 14 allergens UK businesses must declare. NHS and Asthma + Lung UK both flag sulphites as a recognised trigger for bronchoconstriction in a minority of people with asthma. This page is a label-reader's guide to spotting them.
You will not always see the word "sulphite" in an ingredients list. Often the chemical is named, or only the E-number appears. All eight of the following are members of the same family and all release SO₂ in solution:
Functionally they all do the same job — preserving against microbial growth, slowing oxidation and enzymatic browning, controlling fermentation in winemaking — and from a sensitivity standpoint they are interchangeable. If a label declares any one of them above the threshold, treat it as a sulphite-containing product.
Note the spelling. UK labels increasingly use the British "sulphite" / "sulphur dioxide", but legacy packaging and US-derived ingredient lists still use "sulfite" / "sulfur dioxide". Either spelling means the same thing.
Annex II of Regulation (EU) No 1169/2011 — retained in UK food information law — sets the trigger at 10 mg/kg or 10 mg/L expressed as SO₂. Below that, no allergen declaration is required. At or above it, the label must say so, and the words must be emphasised so the reader can pick them out at a glance (UK convention is bold type).
The usual phrasings on a UK pack are:
Because the threshold is set on total SO₂, a product can use any combination of E220–E228 and still trip the same declaration once the cumulative SO₂-equivalent crosses 10 mg/kg. There is no "carry-over" loophole on packaged retail food: if the finished product as sold contains more than 10 mg/kg of SO₂ from any source, it must be declared.
Loose food and food sold without packaging (a bakery counter, a deli, a restaurant) is also covered — UK businesses must make sulphite information available, in writing or on request, under the same allergen rules.
Sulphites are one of the few food additives with a well-documented respiratory effect. The mechanism is straightforward: when an SO₂-containing food or drink is consumed, a small amount of sulphur dioxide gas evolves in the mouth and upper airway, and in some people this provokes bronchoconstriction — the airway narrowing characteristic of an asthma attack.
Published estimates from clinical studies and the FSA's own allergen guidance put the prevalence of sulphite-sensitive asthma at roughly 5–10% of people with asthma, with severe reactions concentrated among those with steroid-dependent asthma. Symptoms can include wheeze, chest tightness, cough and shortness of breath, and onset is typically within minutes of ingestion. NHS guidance recognises sulphites as a recognised trigger and is the reason the FSA includes them in the UK's 14 mandatory allergen declarations.
Two clarifications worth nailing down. First, sulphite sensitivity is not the same as a "sulpha drug allergy". Sulpha drugs (sulphonamides) are an entirely different class of molecule used in some antibiotics; reacting to one does not predict reacting to the other. Second, sulphites in wine are not the established cause of "wine headaches" in the general population — published reviews point to histamines, tannins, congeners and alcohol itself as more likely drivers. Sulphite-driven reactions are predominantly respiratory, not headache-shaped.
If you suspect a sulphite reaction, the practical step is to log it (which food, what dose, what symptom, when it resolved) and take the record to a GP or asthma specialist. We are a tracking tool, not a diagnostic one.
The list is short but commercially important.
Wine. The single largest dietary source of sulphites for most UK adults. Sulphur dioxide is added during winemaking to control fermentation, kill wild yeast and prevent oxidation. White wines typically carry more added SO₂ than reds — reds contain natural antioxidants from grape skins that do some of the work — and dessert and sweet wines, where residual sugar makes spoilage more likely, sit higher still. Conventional white wines commonly fall in the 80–150 mg/L range; pale dessert wines can be higher again. Even wines marketed as "no added sulphites" can carry around 10 mg/L from yeast metabolism alone, which is why nearly every commercially sold wine bottle in the UK still declares "contains sulphites".
Beer and cider. Use is variable. Some ciders and a minority of beers have sulphites added or carried over from concentrate; declarations on UK supermarket packs are the way to tell.
Dried fruit. The colour gives it away. Bright orange dried apricots, pale golden sultanas and uniformly coloured dried apple rings have almost always been treated with sulphites to prevent enzymatic browning. The unsulphited equivalents are visibly darker — brown, almost mahogany apricots; deeper-coloured raisins. Dried mango, dried pineapple and other tropical dried fruits are commonly sulphited too.
Sausages. Traditional British bangers have historically used sulphites (often as sodium metabisulphite, E223) as a preservative; many UK supermarket sausages still declare them. Continental cured meats use nitrites and nitrates instead.
Vinegars, brined vegetables and pre-prepared mustards. Sulphites are a long-standing preservative for malt vinegar, jarred brined vegetables and some made-up mustards.
Frozen prawns and shrimp. Sodium metabisulphite is widely used at the catch or processing stage to prevent melanosis (the harmless dark spotting that develops on prawn shells post-mortem). UK retail packs declare it.
Pre-cut salads and ready-prepared potato. Sulphites were historically used here as anti-browning agents; the use is less common in UK retail today and largely confined to some catering supply chains, but check the label.
Soft drinks and fruit juices. Some fruit juices and concentrates use sulphites as a preservative; declarations are mandatory above the threshold.
Almost every wine bottle in the UK shows the words "contains sulphites". That is the 10 mg/L declaration in action. Two practical points worth knowing:
For someone with documented sulphite-sensitive asthma, "no added sulphites" is not the same as "no sulphites" — talk to a GP or asthma specialist before relying on the distinction.
Sulphites are volatile. Boiling drives off some SO₂ as gas, and soaking dried fruit in water and discarding the soak water removes a meaningful fraction. Neither method is a complete removal, and the residual amount depends on starting concentration, cooking time and surface area. If sulphite avoidance is a clinical need, the safer route is to choose unsulphited dried fruit (the dark brown apricots, for example) rather than rely on cooking to strip them out.
EFSA re-evaluated the sulphite family in 2016 and confirmed a group acceptable daily intake of 0.7 mg SO₂/kg body weight per day across E220–E228. In the same opinion, EFSA noted that high consumers — particularly children — could exceed this ADI under realistic dietary patterns, and flagged the group for further toxicological review. The ADI was retained as a "temporary" figure, reflecting the limitations of the underlying long-term studies. There has been no successor regulation lowering the threshold in retained UK law to date, but the 2016 opinion is the live regulatory position.
Every barcode scan in NutraSafe flags additives in the ingredients list, including the full E220–E228 family — by E-number, named chemical and family label. Free users see the additives surfaced on each scan and can log up to 25 foods per day. NutraSafe Pro (£3.99/month) adds the allergen warning detail panel — which surfaces sulphite presence prominently on packaging that declares them — alongside the AI Coach, full reaction history, processed-food and NRV insights, and the suspected-trigger analysis that lets you correlate sulphite-containing meals with logged symptoms over time. We don't tell you what to do about a reaction; we give you the log to take to a GP or asthma specialist.
Scan any UK pack in NutraSafe and we surface E220–E228 alongside the rest of the additives. Free to log up to 25 foods/day · NutraSafe Pro £3.99/month for AI Coach, allergen warning detail and full reaction history.
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