Sulfites are food additives that are sometimes added to processed foods to enhance flavor and preserve freshness. You'll see them on listed on the food label as:
- Sulfur dioxide
- Potassium metabisulfite
- Potassium bisulfate
- Sodium bisulfate
- Sodium metabisulfite
- Sodium sulfite
Sulfites are useful as food additives because they slow down bacterial growth on foods; improve the quality and texture of bread dough; prevent oxidation, or browning, of sliced raw vegetables and fruit; and reduce the chance of black spots developing on shrimp and lobster.
Sulfites aren't a problem for most people. However, the United States Food and Drug Administration estimates about one percent of the American population are sensitive to sulfites. The FDA also estimates five percent of people who have asthma are allergic to sulfites.
Sulfite sensitivities may start at any time in a person's life, and reactions can be mild, such as a rash or hives, or severe enough to trigger an asthma attack. There are no treatments to block sulfite allergies and severe reactions may require the use of epinephrine, allergy medications or asthma inhalers to reduce the symptoms.
Experts are not yet sure how much sulfite is enough to cause a reaction, or what mechanisms cause the reactions. The reactions and allergy symptoms may occur after eating foods that contain sulfites or maybe even from breathing any fumes that emanate from those foods.
Sulfites are found in wine, bottled lemon or lime juice, dried apricots, molasses, grape juice and sauerkraut. Processed foods like premade gravies and sauces, canned vegetables, condiments, frozen shrimp, dehydrated potatoes, pickled foods, jams and trail mix may also have them, but fresh fruits and vegetables that are meant to be eaten raw are not allowed to contain any sulfites.
Sulfites: Safe for Most, Dangerous for Some. United States Food and Drug Administration. Accessed July 29, 2009. http://vm.cfsan.fda.gov/~dms/fdsulfit.html.