Around 1 in 10 asthmatics react to a food substance known as sulfites. These substances do not cause asthma. Instead it can trigger an asthma attack or worsen asthma symptoms. Sulfites are present in many foods and beverages, particularly processed edibles. It can also be found in certain fruits and vegetables. Sulfites are not only a problem in asthma. It can cause a host of other symptoms beyond the airways in people who are sensitive to sulfites.
About Asthma and Sulfites
Asthma is an airway conditions where airflow through the respiratory passages is impaired due to a narrowing. This narrowing of the airway occurs as a result of sensitivity of the respiratory lining to certain substances. These problem substances may either irritate the lining or trigger an allergic response. The airway swells, excess mucus is produced and the muscles in the airway wall may constrict to cause a narrowing.
The substances that trigger asthma are usually inhaled, such as dust, smoke or pollen. However, some edible substances may also prove to be a trigger in hypersensitive indivdiuals. One of the problem food substances for many asthmatics of all ages is sulfites. This sensitivity to sulfites is not always present from early life. It can develop in adulthood, even in the forties and fifties.
In asthmatics with sulfite sensitivity, there may be bronchospasm when foods containing these substances are consumed. This causes narrowing of the lower airway. The reaction may occur within 15 to 30 minutes of consuming a food containing sulfite. However, the amount of sulfite also determines whether there is a reaction and this can vary among individuals. Some people are more sensitive and others less so.
Read more on common asthma triggers.
Sulfites are not only found in foods. Some medication may also contain sulfites such as certain antibiotics, antiemetics, anesthetics, analgesics, cardiovascular drugs, muscle relaxants, steroids and tranquilizers. Sulfites may also be found in bronchodilator solutions that are used in nebulizers. When these drugs that contain sulfite are injected, it can trigger a reaction within 5 minutes in sensitive individuals.
Overall sulfite sensitivity is rare in non-asthmatics. Apart from triggering asthma attacks or worsening asthma symptoms, sulfites may also cause or trigger nausea, hives (urticaria), angioedema, diarrhea and abdominal cramps. Sulfites can also trigger anaphylaxis, a severe form of allergic reaction, which affects the entire body. It can be life threatening without prompt medical attention.
What are sulfites in foods?
Sulfites (also known as sulphites) are sulfur compounds which are found in many foods and beverages. It is used in food for its preservative and enhancing abilities. Sulfites inhibit microbial growth and therefore prevent foods from spoiling. It also helps certain foods maintain its natural color for longer periods of time. While these compounds are added to several foods, it also occurs naturally and may become concentrated in these foods during preparation.
The following six substances fall within the category of sulfites – sulfur dioxide, sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium bisulfite and potassium metabisulfite. Legislation requires food manufacturers to clearly stipulate when sulfites are added to foods. However, this may not always apply to naturally-occurring sulfites. It is therefore important to know which foods may have sulfites beyond the details on the packaging.
Natural Foods with Sulfites
These are some of the foods with naturally-occurring sulfites. The concentration of sulfites varies among the different foods and may not pose a problem to some sensitive asthmatics if consumed in small quantities.
- Corn starch
- Fish, such as salmon and dried cod
- Maple syrup
Fresh fruits and vegetables, except for potatoes, are not allowed to have any added sulfites beyond those that are naturally occurring due to legislation.
Sulfite Foods for Asthmatics to Avoid
These are some of the foods that may contain sulfites and should therefore be avoided by people who are sensitive/allergic to sulfites. Most of these foods are processed to some degree. Not all asthmatics react to sulfites but it should be considered when other trigger have been eliminated as a problem.
Read more on allergy foods.
Pickles, Sauces and Dressings
Sulfites are commonly used in pickles, salad dressings and sauces as preservatives. This may include fermented foods like sauerkraut as well as pickled meats. Wine vinegar may also contain sulfites. Relishes, avocado dips and guacomole may also be laden with sulfites.
Sulfites may be found in a range of seafood including shellfish and fish. Dried cod, clams (canned), lobster (frozen), salmon, scallops and shrimp (canned, dried, fresh or frozen) are some of the seafood that should be avoided. Even seafood broths without seafood meat can be a problem.
Apple cider, beer, cocktail mixes, wine and wine coolers are some of the alcoholic drinks that may contain sulfites. These sulfites may not always be added to these beverages but be released as part of the fermentation process.
Dried fruit, canned fruit, fruit fillings in puddings, fruits james and jellies as well as bottled lemon/lime and sparkling grape juice may also contain sulfites.
Sufites should be suspected to be in all canned foods, including canned vegetables, fruits, meats and other foods, unless it is clearly specified that it is not present on the can.
A number of convenience foods has sulfites. This includes baked goods (example: cookies, crackers, pizza crust) and fast foods. TV dinners, french fries and mashed potatoe mixes may also contain sulfites.
How to Diagnose a Sulfite Allergy?
Skin or blood tests for a sulfite allergy may not always be positive. Therefore it is necessary to use other methods to identify a sensitivity to sulfite, if an overt allergy to it is undetactable. It is important to consult with a medical professional about the possible approaches to adopt in identifying a food allergy.An elimination diet is one of the ways to identify a sulfite sensitivity.
A food diary should be kept to spot problem foods that may have triggered recent asthma attacks. These foods, as well as other known sulfite-rich foods, should be removed from the diet completely. Gradually each of these potential problem foods should be reintroduced into the diet. If a reaction occurs, the most recent food should be discontinued immediately.