Are sulphites in food harmful? What you need to know about sensitivities

January 13, 2026 •

4 min read

According to the Australasian Society of Clinical Immunology and Allergy (ASCIA), between 5% and 10% of people with asthma may experience adverse reactions to sulphites in food, including wheezing and chest tightness. This raises the question for many: are sulphites in food harmful? The answer is nuanced and depends largely on individual sensitivity, with most people tolerating them without issue.

Quick Summary

Sulphites are common food preservatives that are generally considered safe for most people but can cause allergic-like symptoms in sensitive individuals, especially those with asthma. These reactions are typically intolerances, not true allergies, and can range from mild respiratory issues to severe, though very rare, anaphylactic responses.

Key Points

Sensitivity, Not Allergy: Sulphite reactions are typically a sensitivity or intolerance, most common in individuals with asthma, rather than a true immune system-mediated allergy.
Common Trigger for Asthmatics: Up to 10% of asthmatics may experience adverse respiratory symptoms like wheezing and chest tightness after consuming sulphites.
Sulphites Prevent Spoilage: Added sulphites are effective preservatives that stop microbial growth and prevent the discoloration of many foods and beverages.
Sulphites are Widely Used: They are found in a broad array of processed foods, including wine, dried fruit, sausages, and condiments.
Reading Labels is Crucial: Food products containing sulphites are required to declare them on the label, often listed by name or as E-numbers (E220-E228).
Anaphylaxis is Extremely Rare: While reactions can be severe, including asthmatic episodes, true anaphylactic shock caused by sulphites is very uncommon.
Avoidance is the Main Treatment: The best way to manage a sulphite sensitivity is to identify and avoid foods containing the additive.

What are sulphites?

Sulphites are inorganic salts and sulphur dioxide ($SO_2$) that serve as versatile food additives, primarily functioning as preservatives and antioxidants. Used for centuries, they prevent microbial spoilage, inhibit bacterial growth, and maintain the colour and freshness of many food and beverage products. They are added to a wide range of commercially produced items, from wine and beer to dried fruits and processed potatoes. Some foods, such as wine, also contain naturally occurring sulphites as a byproduct of fermentation. On food labels, sulphites are often identified by their specific E-number, such as E220 for sulphur dioxide, or E221 through E228 for various related compounds.

Why are sulphites used in food production?

Sulphites play a crucial role in modern food production by extending the shelf life of products and preventing spoilage. Their main functions include:

Preventing Oxidation: They act as antioxidants, which stop the browning of foods, especially fruits and vegetables, when exposed to air. This keeps products like dried apricots and shredded potatoes looking fresh and appealing.
Controlling Microbial Growth: Sulphites possess antimicrobial properties that inhibit the growth of bacteria, yeasts, and molds. This is especially important for preserving fermented products like wine and cider.
Stabilizing Medications: Beyond food, sulphites are also used in some pharmaceutical products and cosmetics to maintain the stability and potency of active ingredients.

Sulphite sensitivity: Who is at risk?

While generally safe for the majority of the population, a small subset of individuals, particularly those with asthma, may experience adverse reactions to sulphites. This is more accurately described as a sensitivity or intolerance rather than a true IgE-mediated allergy. The prevalence of this sensitivity is higher among asthmatics, affecting between 5% and 10% of this group. Individuals with severe or poorly controlled asthma may be at an even greater risk.

Common symptoms of sulphite sensitivity

Respiratory: Wheezing, shortness of breath, chest tightness, and coughing are the most common reactions and are triggered when sulphites release sulphur dioxide gas, which can irritate the airways.
Skin: Some people may develop skin rashes, hives (urticaria), or swelling.
Gastrointestinal: Symptoms can include stomach pain, cramps, vomiting, and diarrhea.
Other: Less common symptoms can include a flushed face, rapid heartbeat, dizziness, or a metallic taste in the mouth.

It is important to note that severe, life-threatening anaphylactic reactions to sulphites are extremely rare.

Comparison of sulphite pros and cons


Aspect	Benefits of Sulphites	Potential Harms for Sensitive Individuals
Food Preservation	Prevents browning and spoilage, extending shelf life.	Can trigger asthma attacks and respiratory symptoms.
Microbial Control	Inhibits the growth of bacteria, yeasts, and moulds.	May cause gastrointestinal issues like cramping and diarrhea.
Consumer Safety	Ensures food is safe by preventing bacterial contamination.	Can cause allergic-like skin reactions, including hives and swelling.
Product Appearance	Preserves colour and aesthetic appeal, especially in dried fruits.	Difficult to avoid, as sulphites are widespread in processed foods.

How to identify and manage sulphite sensitivity

For those who suspect a sulphite sensitivity, managing the condition is centered on dietary avoidance. Since a reliable skin-prick or blood test for sulphite sensitivity does not currently exist, a diagnosis is often made based on a patient's history and symptoms, sometimes confirmed by a supervised oral challenge.

Tips for managing sulphite sensitivity:

Read Labels Carefully: Food labels are required to list sulphites if they are present above a certain threshold (10 parts per million in the U.S.). Look for terms like "sulphites," "sulphur dioxide," and the E-numbers E220-E228.
Know Common Sources: Be aware of foods notorious for high sulphite content, including dried fruits, wine, beer, processed meats, and some pre-cut potatoes.
Practice Vigilance at Restaurants: Fresh salads and other prepared foods can sometimes be treated with sulphites to maintain freshness. Always ask restaurant staff about the use of sulphites in their dishes.
Keep a Food Diary: Tracking your food intake and any subsequent symptoms can help you identify triggers and make the connection between sulphite consumption and your reactions.
Choose Sulphite-Free Alternatives: Many products, particularly wines, are now available with low or no added sulphites. Opt for fresh, unprocessed foods whenever possible.

Is it an allergy or an intolerance?

It is crucial to understand the distinction between a true allergy and a sensitivity. A genuine food allergy involves an immune system response mediated by IgE antibodies. In contrast, sulphite sensitivity does not typically involve the immune system in the same way. The adverse reactions are caused by other mechanisms, such as the irritating effect of sulphur dioxide gas on the airways. This distinction is why allergy tests are generally ineffective for diagnosing sulphite sensitivity. For those with a severe sensitivity, carrying emergency medication like an epinephrine auto-injector is advised, despite the reaction not being a true IgE-mediated anaphylaxis.

Conclusion: Making informed choices

For the vast majority of consumers, the sulphites used in food are perfectly safe, and their benefits in preservation and food safety are well-established. However, for the segment of the population with a pre-existing sensitivity, particularly asthmatics, sulphites can be harmful, causing a range of adverse, though typically manageable, symptoms. The key to navigating this issue lies in informed consumer choices, diligent label reading, and recognizing personal triggers. The ongoing re-evaluation by bodies like the European Food Safety Authority continues to scrutinize the acceptable daily intake, reflecting the need for ongoing research into this common food additive.

Sources and further reading

Healthline: What Are Sulfites—and Should You Avoid Sulfite-Rich Foods?
Food Standards Australia New Zealand: Sulphites

Frequently Asked Questions

Sulphites are chemical compounds containing the sulfite ion ($SO_3^{2-}$) and are used as preservatives and antioxidants in many food products. They occur both naturally in some foods and are added during processing.

Individuals with asthma are most at risk of sulphite sensitivity. Studies show that between 5% and 10% of asthmatics can experience adverse, allergy-like reactions to sulphites.

Common symptoms include respiratory issues like wheezing and chest tightness. Other reactions can affect the skin (hives, rashes) and the digestive system (stomach pain, diarrhea). Severe reactions are rare.

No, sulphite reactions are typically sensitivities or intolerances, not true IgE-mediated allergies. The immune system is not involved in the same way as with a conventional food allergy.

Foods with notoriously high sulphite levels include wine, beer, dried fruits (like apricots), sausages, processed potatoes (frozen fries, dehydrated), and bottled lemon or lime juice.

The most effective method is reading food labels carefully for the word 'sulphites' or the E-numbers E220-E228. Also, focus on consuming fresh, unprocessed foods and be cautious with fermented or preserved items.

Yes, some studies suggest that children who are high consumers of certain sulphite-containing foods, such as cordials and dried fruit, may exceed the acceptable daily intake. Parents of asthmatic children should be particularly vigilant.

No, while some producers state no sulphites were added, very low levels are still naturally present as a byproduct of the fermentation process.