Is sodium sulphite bad for you?

December 6, 2025 •

3 min read

According to the FDA, an estimated 1 out of 100 people is sensitive to sulfites in food or wine, leading to concern about whether is sodium sulphite bad for you. This common food preservative is generally safe for most individuals, but can trigger allergy-like symptoms in susceptible people, especially asthmatics.

Quick Summary

Sodium sulphite, a widely used food additive, is generally recognized as safe for the public. However, a small portion of the population with sulfite sensitivity may experience adverse reactions, including severe asthmatic symptoms.

Key Points

Generally Safe: Sodium sulphite is an approved food preservative, safe for most people when consumed within regulated levels.
Sensitivity, Not Allergy: Reactions to sulphites are typically sensitivities or intolerances, not true allergies involving the immune system.
Asthmatics at Higher Risk: People with asthma are a key risk group, with 5-13% potentially reacting to sulphites.
Varied Symptoms: Reactions can cause respiratory, skin, and digestive issues, ranging from mild wheezing to severe anaphylaxis.
Widespread Use: Sodium sulphite is found in many products, including dried fruits, wine, processed potatoes, and some medications.
Avoidance is Key: For sensitive individuals, reading labels and avoiding products containing sulphites is the primary management strategy.
Sulfite vs. Sulfa: Sulphite sensitivity is different from a sulfa drug allergy, and there is no cross-reactivity.

What is Sodium Sulphite?

Sodium sulphite ($Na_2SO_3$) is an inorganic salt widely used as a preservative and antioxidant in the food industry. As a food additive, its primary function is to prevent spoilage, inhibit microbial growth, and stop foods from browning due to oxidation. It is commonly found in dried fruits, baked goods, processed meats, and, perhaps most famously, in wines and beers. Sulfites can also occur naturally during fermentation.

Sulphite Sensitivity vs. True Allergy

For the vast majority of people, consuming sodium sulphite in regulated amounts poses no health risk. The potential problems are almost exclusively confined to a small subset of the population with a sulfite sensitivity or intolerance. It is important to distinguish this from a true IgE-mediated allergy, which is extremely rare for sulfites. Sensitivity reactions, though not a true allergy, can still cause significant and sometimes severe symptoms in susceptible individuals. Some of the proposed mechanisms for sulfite sensitivity include the inhalation of sulfur dioxide gas released from the sulphite in the stomach, or a deficiency in the enzyme sulfite oxidase, which is needed to break down sulphites.

Symptoms of Sulphite Sensitivity

Reactions to sulphites can vary widely in severity and type, though they often affect multiple body systems. The symptoms can appear quickly, within 15 to 30 minutes of ingestion, and range from mild to life-threatening.

Commonly reported symptoms include:

Respiratory: Wheezing, coughing, chest tightness, shortness of breath, and nasal congestion. This is the most common form of reaction, particularly in asthmatics.
Dermatological: Hives (urticaria), skin rashes, redness, itching, and swelling of the face, lips, or tongue.
Gastrointestinal: Nausea, vomiting, diarrhea, and abdominal pain.
Cardiovascular: Flushing, dizziness, and low blood pressure.
Severe reactions: In rare cases, sulphite sensitivity can lead to anaphylaxis, a severe, full-body reaction that can cause collapse and circulatory issues.

Who is at Risk?

While anyone can develop a sensitivity at any time, certain groups are at a higher risk of adverse reactions.

Asthmatics: This group is disproportionately affected by sulfite sensitivity, with an estimated 5–13% experiencing symptoms after ingesting sulfites. Asthmatics who are steroid-dependent or have marked airway hyperresponsiveness are at greater risk.
General Population: The FDA estimates that less than 1% of the general population has a sulfite sensitivity. Adverse reactions in non-asthmatics are considered extremely rare.

Sodium Sulphite in Foods and Medications

Sodium sulphite and its related compounds (like potassium metabisulphite) are widespread, serving as indispensable preservatives for food manufacturers. However, regulatory bodies like the FDA have placed restrictions on their use in certain foods due to safety concerns for sensitive individuals.

Foods that often contain added sulphites:

Dried fruits (especially apricots and raisins)
Wines and beers (both natural and added)
Pickled foods and condiments
Fruit juices
Processed potatoes (pre-cut or dehydrated)
Certain baked goods and dough products

Sulphites are also present in some medications, cosmetics, and topical treatments as a stabilizer.

Managing Sulphite Sensitivity

For those who are sensitive, the primary management strategy is to avoid sulphite-containing products. Reading food labels is critical for this purpose. Ingredients to watch for include:

Sodium sulfite
Sulfur dioxide
Potassium bisulfite
Potassium metabisulfite
Sodium metabisulfite

Sulfite Sensitivity vs. Sulfa Allergy

It is important not to confuse sulfite sensitivity with a sulfa allergy. A sulfa allergy is a reaction to sulfonamide-containing antibiotics, which are chemically unrelated to sulfites.


Feature	Sulphite Sensitivity	Sulfa Allergy
Trigger	Sulphite additives ($SO_3^{2-}$) and naturally occurring sulphites	Sulfonamide-containing drugs like some antibiotics
Mechanism	Non-immune sensitivity reaction, possibly enzyme deficiency or chemical irritation	True IgE-mediated immune system response to the sulfa drug
Symptoms	Respiratory, skin, and gastrointestinal reactions. Can trigger asthma.	Skin rashes, fever, and in severe cases, anaphylaxis.
Cross-Reactivity	No cross-reactivity with sulfa drugs or sulfates.	No cross-reactivity with sulfites.

Conclusion

For the majority of the public, sodium sulphite is a safe and effective preservative regulated by food safety authorities like the FDA. The real health concerns are concentrated among a small percentage of the population with sulphite sensitivity, particularly asthmatics, who can experience a range of mild to severe allergy-like symptoms. For these individuals, careful label reading and avoidance are key to managing symptoms and preventing adverse reactions. Individuals with severe sensitivities should carry an emergency epinephrine auto-injector.

For more detailed information on regulations and safety, consult the FDA's guidance on food additives.

Frequently Asked Questions

Sulphites are primarily used as a food preservative and antioxidant to prevent discoloration, stop microbial growth, and extend the shelf life of food and beverages like dried fruits, wine, and processed vegetables.

While often blamed for wine headaches, there is little scientific evidence to support this claim. Headaches are more likely linked to other wine components like histamines and tannins, or simply dehydration from alcohol consumption.

Sulphite sensitivity is not very common in the general population, affecting an estimated less than 1%. However, the incidence is significantly higher among asthmatics, with up to 13% experiencing symptoms.

Sulphites can be both naturally occurring and added. They are a natural byproduct of the fermentation process in foods like wine, but are also added deliberately as a preservative.

If you experience symptoms of a severe reaction, such as difficulty breathing, swelling of the throat, or dizziness, you should seek immediate emergency medical treatment. Those with known severe sensitivities should carry an epinephrine auto-injector.

Yes, all wines contain some level of naturally occurring sulphites produced during fermentation. However, some winemakers choose not to add extra sulfites, and wines labeled "organic" in the U.S. have stricter limits on or prohibition of added sulphites.

In many countries, including the US and EU, packaged foods with sulphite levels of 10 parts per million (ppm) or more must declare the presence of sulfites on the label. Checking the ingredient list for terms like "sodium sulphite" is the best approach.

Sulphites cannot be effectively removed from food by washing or cooking. The best way to avoid them if you are sensitive is to read labels and avoid the food entirely.