Sulfite is the name given to a class of commonly used preservatives that reduce spoilage, act as antioxidants, and prevent fruit and vegetable browning. They may be present in baked goods, condiments, shrimp, certain wines (white wine usually more than red wine) and beer. They are present in dried fruits in high quantities. Since 1986, the FDA has banned them in most fresh fruits, vegetables, and salad bars. Asthma exacerbations, anaphylaxis, and urticaria have all been reported from reactions to sulfites, and the FDA requires labeling on any food or beverage with greater than 10 parts per million of these preservatives. Some common names include sulfur dioxide, potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium metabisulfite, or sodium sulfite. There is currently no reliable blood or allergy skin test to test for sulfite reactions.
Sulfa drugs, antibiotics and other medicines that contain a sulfonamide molecule, are not the same thing as sulfites.
Sulfates are salts of sulfuric acid and are present in many medicines, supplements, and personal care products – they are not the same thing as sulfites or sulfa drugs.
Sulfur is an element that is essential for life, and is found in sulfites, sulfates, and sulfonamides, but by itself is not responsible for the reactions people have to these other molecules. Elemental sulfur can rarely cause problems if inhaled.
Find out more about food allergyies and the relationshop to dyes, sulfites and other food additives.