Propylene Glycol vs Sodium Sulfite: which is worse?
Quick answer: Sodium Sulfite carries the heavier risk profile. Propylene Glycol is — in the EU and — in the US; Sodium Sulfite is — in the EU and — in the US.
| Property | Propylene Glycol | Sodium Sulfite |
|---|---|---|
| EU status | — | — |
| US status | — | — |
| Risk level | — | — |
| Banned in | — | — |
| Restricted in | European Union (not permitted as a direct food additive in most food applications; only permitted as a carrier solvent for specific additives at low levels) | 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 Propylene Glycol?
Propylene glycol is a synthetic organic compound used as a humectant, solvent, and emulsifier in food, pharmaceuticals, cosmetics, and industrial applications. It is produced from propylene oxide (derived from petroleum). Its chemical formula is C3H8O2.
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
Propylene Glycol: Propylene glycol is generally considered safe by the FDA and is metabolized by the liver to lactic acid and pyruvate (normal metabolites). However, at high doses — particularly from intravenous pharmaceutical formulations — propylene glycol can accumulate and cause lactic acidosis, kidney toxicity, and CNS effects. These effects are seen in critically ill patients receiving high-dose PG-containing intravenous medications, not from food consumption. In children and people with impaired liver or kidney function, PG accumulation may occur at lower doses than in healthy adults. Animal studies have found reproductive and developmental effects at high doses. EFSA's 2018 re-evaluation found no concerns at typical food use levels but noted the EU limits PG use as a direct food additive, using it only as a carrier solvent for permitted additives.
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.
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