What is The Big Deal With Sulfites?
What are Sulfites?
Sulfites, also called Sulfiting Agents, have been used since the 1660’s as preservatives because of their antibacterial,
antioxidant, and anti-browning properties.   They are added to a variety of foods such as fruits, vegetables, shellfish, and baked
goods  to prevent spoilage.  Sulfites are also found naturally in fermented drinks such as wine and beer but wine makers often
add extra sulfiting agents to help preserve it longer.  Sulfites are also found in some types of medications to help prevent bacteria
growth.

Sulfite Sensitivity
The vast majority of adverse events related to sulfites occur in asthmatic individuals.  Some believe that as many as 5% of
asthmatics are sensitive to sulfites.   Usually, this occurs in patients with difficult to control asthma.   Respiratory symptoms
(shortness of breath, chest tightness, wheezing) usually develop within 15-30 minutes of ingestion.   Other symptoms, such as
rashes (including hives and angioedema), nausea, abdominal cramping, and diarrhea have been reported in non-asthmatic
individuals, but this is rare.   While they are often blamed for wine headaches, sulfites are not felt to be the cause.   While the
cause of sulfite reactions is unknown, the majority are not allergic in nature.   Allergic reactions to sulfiting agents are extremely
rare, with only a very few cases reported in the medical literature.  One explanation is that sulfite is metabolized into sulfur dioxide
which irritates the lungs of some asthmatics.     

What should I avoid?
Avoiding sulfites can be difficult as they are found in many different types of foods including:

  • Dried fruits (except prunes and raisins), canned vegetables, guacamole
  • Fresh and concentrated lemon and lime juice (frozen is OK)
  • Molasses, jams, maple syrup
  • Sauerkraut
  • Grape juice
  • Pickled onions, peppers, and pickles
  • Dried, frozen, and canned potatoes
  • Wine vinegar
  • Gravy, soup mixes
  • Beverages such as wine, beer, hard cider, and some soft drinks
  • Pizza and pie crust
  • Beet sugar
  • Cookies, crackers
  • Shrimp

They key is to read labels carefully.   Foods containing sulfites should be labeled with one of these terms: sulfur dioxide, sodium
bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, sodium sulfite, sulfite, or sulfiting agents.
                                         
Sulfites and Medications
Sulfites are also found in some medications—usually injectables such as steroid injections, dental anesthetics, and some
antibiotics.    Sulfite is also found in the epinephrine injectors use for allergic reactions.  Although there might be a small risk of a
reaction from the sulfite  in an epinephrine injector, even sulfite sensitive people should use them as the benefits of the
medication far outweigh the risks.   

Sulfite sensitivity is not to be confused with sulfur sensitivity.  There are some medications that contain sulfur molecules.   One
example is the antibiotic Septra (also called Bactrim or trimethoprim/sulfamethoxazone).  There is no cross-reactivity between
this type of medication and sulfites.

Sources:
Sulfite Sensitivity: Significance in Human Health J Am Coll Nutr 1995 Jun;14(3):229-32.
Middleton’s Allergy Principles and Practice, 6th Edition
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