Sulfites (or sulphites) describe a group of compounds containing the SO32- ion.
Sulfites are added to foods for the following reasons:
- As a preventives
- To inhibit oxidation (“browning”) of light-colored fruits and vegetables, such as dried apples and dehydrated potatoes.
- Prevent melanosis (“black spot”) on shrimp and lobster
- Reduce bacterial growth as wine ferments
- “Condition” dough
- Bleach food starches
- Maintain the stability and potency of some medications.
Sulfites seem pretty useful as a food additive.
They are also a natural byproduct of fermentation, so all beer and wine contains at least some sulfites. Producers sometimes add sulfites as well.
Some people are allergic to sulfites, especially asthmatics. According to the FDA, of all the reports they receive about adverse food reactions, reactions to sulfites are most likely to cause a true allergic reaction.
Responses range from mild to life-threatening.
According to the FDA:
A person can develop sulfite sensitivity at any point in life, and no one knows what triggers onset or the mechanism by which reactions occur. “Doctors believe that asthmatics develop difficulty breathing by inhaling sulfite fumes from treated foods,” notes Dan Atkins, M.D., a pediatrician at the National Jewish Center for Immunology and Respiratory Medicine in Denver, Colo. He says that in a severe reaction an overwhelming degree of bronchial constriction occurs, causing breathing to stop. This can lead to lack of oxygen reaching the brain, heart, and other organs and tissues and, possibly, a fatal heart rhythm irregularity.
“We now know that asthmatics who have more severe symptoms and are dependent on corticosteroids, such as prednisone or methylprednisolone, are especially prone to sulfite sensitivity and are most at risk of having a severe reaction,” notes Atkins. But it’s a chicken-and-egg situation, notes Simon: “We don’t know which comes first, the asthma or the sulfite sensitivity, because some people’s first experience with asthma is a sulfite reaction, and as their asthma becomes more severe they eventually become steroid-dependent.”
Click the link for a list of foods containing sulfites.
In the USA, the FDA requires that all foods containing sulfites be labeled as such. Other countries are expected to follow this lead.
Other Names for Sulphites
Scan the list of ingredients for the following:
- E 220, E 221, E 222, E 223, E 224, E 225, E 226, E 227, E 228 (European codes)
- Potassium bisulphite/metabisulphite
- Sodium bisulphite/dithionite/metabisulphite/sulphite
- Sulfur dioxide
- Sulphiting agents
- Sulphurous acid