Sulfur Dioxide vs Sodium Sulfite: which is worse?
Quick answer: Sodium Sulfite carries the heavier risk profile. Sulfur Dioxide is — in the EU and — in the US; Sodium Sulfite is — in the EU and — in the US.
| Property | Sulfur Dioxide | Sodium Sulfite |
|---|---|---|
| EU status | — | — |
| US status | — | — |
| Risk level | — | — |
| Banned in | — | — |
| Restricted in | European Union (ADI 0.7 mg/kg body weight; mandatory 'contains sulfites' labeling in wine and food), United States (banned from fresh produce 1986; mandatory labeling above 10 ppm) | United States (banned from fresh produce and salad bars per FDA 1986 action), European Union (ADI 0.7 mg/kg body weight as sulfur dioxide equivalent), Australia (mandatory labeling if above 10 ppm) |
| Category | additive | additive |
| Where it hides | — | — |
What is Sulfur Dioxide?
Sulfur dioxide (SO2) is a colorless gas used as a food preservative and antioxidant. It is the primary active form of the sulfite family of food additives. It is generated by burning sulfur or as a byproduct of certain chemical processes. In food use, it is released from various sulfite salts (E221-E228) and directly applied to some foods.
What is Sodium Sulfite?
Sodium sulfite is an inorganic sulfite salt used as a food preservative and antioxidant. It releases sulfur dioxide when it contacts water or acid, which acts as the active antimicrobial and antioxidant agent. Part of the broader sulfite family of food additives (including sulfur dioxide E220, sodium bisulfite E222, and others).
Documented risks
Sulfur Dioxide: Same as sodium sulfite: sulfite-sensitive individuals (1% of population, 5% of asthmatics) can experience severe reactions. SO2 in wine has been identified as a contributor to wine-induced headache and asthmatic episodes. Occupational exposure to SO2 gas causes respiratory irritation, bronchospasm, and lung damage at higher concentrations — relevant to workers in winemaking and food processing but not typical dietary exposure levels.
Sodium Sulfite: Sulfites are among the more significant food allergy/intolerance triggers. An estimated 1 in 100 people, and up to 5% of asthmatics, are sulfite-sensitive. Reactions can include urticaria, angioedema, bronchospasm, and in severe cases anaphylaxis. Sulfite-induced asthma can be severe; several deaths attributable to sulfite-triggered anaphylaxis have been documented. The FDA banned sulfites from fresh produce and restaurant salad bars in 1986 after several deaths and severe reactions were linked to sulfite-treated salads. FDA mandates that sulfite content above 10 ppm be declared on US food labels. All forms of sulfites (E220-E228) share these sensitization concerns.
Scan a barcode and we'll flag both Sulfur Dioxide and Sodium Sulfite (plus 200+ other ingredients banned overseas).
Scan free →