Premium Nahrungsergänzungsmittel | artgerecht

Sodium Sulphite (E221): Uses, Effects & Safety

Sodium sulphite (E221) is a food additive used as a preservative and antioxidant. It protects food from oxidation and microbial spoilage, and is found in wine, dried fruit, and seafood.

Regular tips about health Regular tips about health

Things worth knowing about "Sodium sulphite"

Sodium sulphite (E221) is a food additive used as a preservative and antioxidant. It protects food from oxidation and microbial spoilage, and is found in wine, dried fruit, and seafood.

What is Sodium Sulphite?

Sodium sulphite (chemical formula: Na₂SO₃) is an inorganic salt of sulphurous acid. In the food industry, it is authorised under the EU additive number E221 and is used as a preservative and antioxidant. It belongs to the group of sulphites, which also includes sodium hydrogen sulphite (E222), sodium metabisulphite (E223), and several related compounds. As a white, crystalline powder that dissolves readily in water, sodium sulphite is used across a wide range of food products as well as in technical and pharmaceutical applications.

Use in the Food Industry

Sodium sulphite is used in food processing primarily for two purposes:

Preservation: It inhibits the growth of bacteria, yeasts, and moulds, thereby extending the shelf life of food products.
Antioxidant: It prevents both enzymatic and non-enzymatic browning (e.g. in dried fruit, vegetables, and wine) by blocking oxidative processes.

Typical foods that may contain sodium sulphite include:

Dried fruit (e.g. dried apricots, raisins)
Wine and fruit juices
Seafood and fish products
Potato products (e.g. chips, potato waffles)
Starch and starch-based products
Vinegar and mustard

Mechanism of Action

In aqueous solution, sodium sulphite releases sulphite ions (SO₃²⁻) and sulphurous acid (H₂SO₃). These compounds act on multiple levels:

They react with reactive oxygen species, interrupting oxidative chain reactions.
They inhibit enzymes such as polyphenol oxidase, which is responsible for the browning of fruit and vegetables.
They disrupt the cellular metabolism of microorganisms, providing an antimicrobial effect.

Technical and Pharmaceutical Applications

Outside the food industry, sodium sulphite is used in several other fields:

Photography: As a developing agent and fixing component.
Textile and paper industry: As a bleaching and reducing agent.
Water treatment: To remove chlorine from drinking water and industrial water supplies.
Pharmaceuticals: As an antioxidant in injectable solutions and medicines to protect active ingredients from oxidation.

Health Aspects and Tolerability

For most people, sodium sulphite in the amounts found in food is considered safe. The European Food Safety Authority (EFSA) has established an acceptable daily intake (ADI) of 0.7 mg per kilogram of body weight per day for all sulphites combined.

However, certain groups of people may be sensitive to sulphites:

Asthma patients: Sulphites can trigger bronchospasm in a subset of asthma sufferers. It is estimated that approximately 5-10% of people with asthma are sulphite-sensitive.
Individuals with sulphite intolerance: Possible symptoms include skin reactions, gastrointestinal complaints, headaches, and, in rare cases, severe allergic reactions.
Individuals with sulphite oxidase deficiency: This rare inherited enzyme deficiency prevents the normal breakdown of sulphites in the body and can lead to serious neurological problems.

Labelling Requirements

Under the EU Food Information Regulation (FIR, Regulation (EU) No 1169/2011), sulphites -- including sodium sulphite -- must be declared on food labels when the concentration in the final product exceeds 10 mg/kg or 10 mg/l. They are among the 14 major allergens subject to mandatory labelling in the EU. On labels, they appear as sulphites, sulphur dioxide, or under their E-numbers (E220-E228).

Metabolism in the Body

In the human body, sodium sulphite is metabolised by the enzyme sulphite oxidase, which converts it into harmless sulphates that are then excreted in the urine. In healthy individuals, this process is efficient, meaning that an excessive accumulation of sulphites in the body is not expected under normal dietary conditions.

References

European Food Safety Authority (EFSA): Re-evaluation of sulphur dioxide (E 220), sodium sulphite (E 221), sodium bisulphite (E 222), sodium metabisulphite (E 223), potassium metabisulphite (E 224), calcium sulphite (E 226), calcium hydrogen sulphite (E 227) and potassium hydrogen sulphite (E 228) as food additives. EFSA Journal, 2016.
Regulation (EC) No 1333/2008 of the European Parliament and of the Council on food additives.
Regulation (EU) No 1169/2011 of the European Parliament and of the Council on the provision of food information to consumers (Food Information Regulation).

Building Blocks for a Healthy Life

As an integrated manufacturer, we develop & produce evidence-based, patented, and non-patented formulations. We work exclusively with plant and natural extracts according to the strictest purity & quality standards.
The combination of science & modern technology with the laws of nature creates solutions consistently tailored to humans – for the highest good: health.