What are sulfites in food/ allergies
The excellent news is that sulfites generally don't cause problems in people without allergies and asthma, even when large amounts are consumed. However, in 3 to 10 percent of people with asthma, sulfites are known to increase asthma symptoms love wheezing, chest tightness, and coughing. This generally occurs in adults with severe and/or poorly controlled disease.
Numerous well-controlled studies show that some asthmatics can own severe asthma symptoms after eating sulfite-containing foods/beverages or inhaling sulfite fumes or vapors.
Less is known about developing hives/swelling and anaphylaxis as a result of sulfites, although various cases own been described in which consuming sulfite-containing foods/beverages led to severe allergic reactions. Some of these people even had positive skin tests for sulfites, suggesting allergic antibodies to the preservative were present.
Other people own experienced severe reactions from sulfite-containing medications, including intravenous drugs and inhaled medications.
These reactions included flushing, hives, and a drop in lung function as a result of taking the medications.
Sulfites don't appear to be a culprit in people suffering from repeated episodes of anaphylaxis of unknown cause. They're also not a risk for anaphylaxis in people with mastocytosis, a rare disorder caused when an excessive number of mast (immune) cells collect together and appear to present little to no risk for people without asthma and without atopy, the genetic tendency to develop allergic diseases.
Why Sulfites Are Added to Foods
Sulfites are added to foods for various reasons. These include:
- Reducing bacterial spoilage
- Conditioning of dough in the frozen pie and pizza crust
- Slowing the browning of fruit, vegetables, and seafood
- Inhibiting growth of bacteria during fermentation of wines
- Bleaching effect for maraschino cherries and hominy
In the past, sulfites were added to unused foods in restaurants and grocery stores to prevent browning.
An increase in reactions led the Food and Drug istration (FDA) to ban the use of sulfites in unused foods in 1986, particularly on unused lettuce in salad bars.
Foods That Contain Sulfites
There are a number of foods that contain sulfites.
Greater than 100 ppm of sulfites (very high levels; strict avoidance advised in people with sulfite allergy)
- Bottled lemon juice (non-frozen)
- Sauerkraut (and its juice)
- Bottled lime juice (non-frozen)
- Dried fruits (excluding dark raisins and prunes)
- Grape juices (white, white sparkling, pink sparkling, red sparkling)
- Pickled cocktail onions
Between 50 and 99.9 ppm of sulfites (moderate to high levels of sulfite; avoidance advised in people with sulfite allergy)
- Dried potatoes
- Fruit toppings
- Wine vinegar
- Maraschino cherries
Between 10 and 49.9 ppm of sulfites (low to moderate levels of sulfite, may cause symptoms in people with severe sulfite allergy)
- Cornbread/muffin mix
- Imported sausages and meats
- Imported jams and jellies
- Pickled peppers
- Avocado dip/guacamole
- Clam chowder
- Corn syrup
- Various cheeses
- Maple syrup
- Dehydrated vegetables
- Imported fruit juices and soft drinks
- Frozen potatoes
- Cordials (alcoholic)
- Fresh mushrooms
- Fresh shrimp
- Canned/jarred clams
- Ciders and cider vinegar
Less than 10 ppm of sulfites (very low sulfite levels, generally do not pose a risk, even for people with sulfite allergy)
- Dry soup mix
- Soft drinks
- Beet sugar
- Frozen pizza and pie dough
- Malt vinegar
- Canned potatoes
- Domestic jams and jellies
- Fresh fruit salad
- High fructose corn syrup
While there own been some case reports of people being diagnosed with sulfite allergy using skin testing, there's no dependable, commercially available skin test for sulfite allergy.
Typically, the diagnosis is suggested by a history of adverse reactions after consuming sulfite-containing foods or medications.
In order for the diagnosis to be confirmed, an allergist may act out an oral challenge for a patient suspected of having a sulfite allergy. This procedure involves giving a person increasing amounts of sulfites to swallow while closely monitoring lung function and vital signs. A significant drop in lung function confirms sensitivity to sulfites.
This test should only be performed under the direct supervision of a physician who's been trained and is experienced with this procedure.
The immune system
The immune system protects the body by producing specialised proteins called antibodies.
Antibodies identify potential threats to your body, such as bacteria and viruses.
They signal your immune system to release chemicals to kill the threat and prevent the spread of infection.
In the most common type of food allergy, an antibody known as immunoglobulin E (IgE) mistakenly targets a certain protein found in food as a threat. IgE can cause several chemicals to be released, the most significant being histamine.
Histamine causes most of the typical symptoms that happen during an allergic reaction.
For example, histamine:
- causes little blood vessels to expand and the surrounding skin to become red and swell up
- affects nerves in the skin, causing itchiness
- increases the quantity of mucus produced in your nose lining, which causes itching and a burning sensation
In most food allergies, the release of histamine is limited to certain parts of the body, such as your mouth, throat or skin.
In anaphylaxis, the immune system goes into overdrive and releases large amounts of histamine and numerous other chemicals into your blood.
This causes the wide range of symptoms associated with anaphylaxis.
Medications That Contain Sulfites
Sulfites are added to some medications for their antioxidant properties as well as to prevent browning (discoloration) of medications. Sulfites are added to injectable epinephrine (for example, the EpiPen) to prevent browning, which decreases the effectiveness of the drug.
However, epinephrine has not been reported to cause adverse reactions in people with a sulfite allergy and should not be withheld in an allergic emergency.
Injectable epinephrine may prove life-saving in people with a sulfite allergy who are experiencing anaphylaxis.
Some inhaler solutions used to treat asthma contain sulfites, although numerous asthma drugs own had sulfites removed due to safety concerns. People with a sulfite allergy should avoid medications containing sulfites, except for injectable epinephrine (for example, EpiPen and Twinject).
Here are examples of medications that contain sulfites:
The FDA now requires that any food containing more than 10 parts per million (ppm) concentration of sulfites to be declared on the label. This is because foods that contain less than 10 ppm of sulfites own not been shown to cause symptoms, even in people allergic to sulfites.
The Codex Alimentarius Commission (part of the World Health Organization and the Foodand Agriculture Organization program of the United Nations and will be referred to as ‘Codex’ in this document) lists sulfites as one of the priority ‘allergens’.
Of course, sulfites do not cause allergic reactions but can elicit adverse reactions upon ingestion in a little percentage of consumers.
Codex placed sulfites on the priority list to provide guidance to individual countries by indicating that the labeling of sulfites was significant to protect sulfite-sensitive consumers.
Sulfites are used as food additives for a variety of applications. In most countries, sodium and potassium sulfite (NaHSO3, KHSO3), sodium and potassium metabisulfite (Na2S2O5, K2S2O5), sodium sulfite (Na2SO3) are allowed along with sulfur dioxide gas (SO2). In some countries, potassium sulfite (K2SO3) and sulfurous acid (H2SO3) are allowed.
Some countries restrict certain uses of sulfite. The U.S. has a long-standing restriction on use of sulfites in meats, but this restriction does not exist in most other countries. The U.S. also prohibits the use of sulfites on unused fruits and vegetables (salad bars, etc.) intended to be consumed raw.
Sulfites may also happen naturally in some foods especially fermented foods as some strains of yeast can produce sulfite from sulfate that exists in much larger quantities in nature.
However, naturally occurring levels of sulfite are typically fairly low (<10 ppm entire SO2).
Labeling regulations for sulfites vary from one country to another. But, numerous countries require the declaration of the presence of sulfites in foods when residue levels exceed some specified concentration. Commonly, 10 ppm entire SO2 is the specified concentration and this is the level specified in the U.S. Entire SO2 can be sure by several methods but the optimized Monier-Williams distillation-titration procedure is the most widely accepted (Official Method 990.28 in Official Methods of Analysis of AOAC International, 17th edition.
2000. Dr. William Horowitz, Ed. Gaithersburg, MD USA).
Sulfur dioxide (SO2), sodium bisulfite (NaHSO3), potassium metabisulfite (KHSO3), sodium metabisulfite (Na2S2O5), potassium metabisulfite (K2S2O5), and sodium sulfite (Na2SO3) are allowed as food ingredients in the U.S.
These substances are considered as GRAS (Generally Recognized as Safe).
The U.S. Foodand Drug istration (FDA) requires that the presence of sulfites be declared on food labels when used as an ingredient in the food and also when used as a processing aid or when present in an ingredient used in the food (e.g. dried fruit pieces). Sulfites must be declared in these cases when the concentration in the food is ≥10 ppm entire SO2. [21 CFR 101.100 (a)(4) «For the purposes of paragraph (a)(3) of this section, any sulfiting agent (sulfur dioxide, sodium sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, and potassium metabisulfite) that has been added to any food or to any ingredient in any food and that has no technical effect in that food will be considered to be present in an insignificant quantity only if no detectable quantity of the agent is present in the finished food.
A detectable quantity of sulfiting agent is 10 parts per million or more of the sulfite in the finished food.»] If naturally occurring sulfites also exists in foods, it would contribute to the analytical result. Basically, if the food contains≥ 10 ppm entire SO2, then sulfite must be declared on the label. This will most typically happen when sulfite is deliberately added to the food. The specific name of the additive (e.g. sodium bisulfite) must be declared in the case of use as an intentional ingredient.
Sulfites are also prohibited from certain uses in the U.S.
Sulfites may not be used in products such as meats that serve as a excellent source of vitamin B1 because sulfites can scavenge that vitamin from foods. In 1986, following the identification of numerous cases of sulfite-induced asthma occurring on ingestion of green or fruit salads treated with sulfites, FDA prohibited the use of sulfites on fruits and vegetables intended to be served raw or presented unused to the public (Fed. Regist. 51:25021-25026, 1986). The only exception is sulfite use on minimally processed potatoes sliced or shredded for frying where sulfite use is still permitted (although FDA has a long-standing, though never finalized, proposal to ban that use also).
Sulfite use as a fungicide during the shipment of unused table grapes is regulated by the U.S. Environmental Protection Agency, but the concentration of SO2 residues on the table grapes as consumed must be <10 ppm entire SO2.
The labeling of the presence of sulfites on alcoholic beverages is under the jurisdiction of the Taxand Trade Bureau (TTB) of the U.S. Dept.
of Treasury. While most ingredients in alcoholic beverages are not declared on the container, the presence of sulfites must be declared. Sulfites are commonly used in wine fermentation to control undesirable growth of acid-producing bacteria while allowing alcohol-producing yeast to proliferate.
Total SO2 levels in foods and beverages should be sure by the optimized Monier-Williams distillation-titration procedure, a method approved by the Association of Official Analytical Chemists (AOAC). Alternate methods do exist but FDA and other federal agencies will typically use the AOAC method so any alternative method must provide similar results.
Food products that contain undeclared sulfites at levels above 10 ppm entire SO2 will be subject to potential recall actions.
In the U.S., three recall categories are used:
- Class I recalls are the most serious and involve situations where there is a reasonable probability that exposure to the violative product will cause serious adverse health consequences or deaths. FDA is aware of deaths occurring among sulfite-sensitive asthmatics.
- Class II recalls include situations where exposure to the violative product may cause temporary or medically reversible adverse health consequences or where the probability of serious adverse health consequences is rare.
- Class III recalls includes situations where exposure to the violative product is not likely to cause adverse health consequences.
For sulfites, recalls can drop into any of the 3 recall classifications.
Using data from controlled oral clinical challenges of sulfite-sensitive asthmatics, the FDA has established dose levels that are associated with Class I, Class II, or Class III recalls. Analysis is done for entire SO2 based upon the AOAC procedure. The analytical result is given in terms of a concentration (ppm). FDA determines a worst case dose (mg SO2 equivalents) by using the 95th percentile level of consumption of the food in question.
Dose estimates are based upon single occasion exposures. The estimated 95th percentile sulfite ingestion dose (in mg) for a single occasion is then obtained by multiplying the sulfite concentration of the food product (in ppm or mg per kg of food) by the 95th percentile level of food consumption (in kg) for the specific food.
|Class||Est. 95th Percentile Dose|
|Class I||≥10 mg|
|Class II||3.7 — 9.9 mg|
|Class III||< 3.7 mg|
Timbo B, Koehler KM, Wolyniak C, Klontz KC.
2004. Sulfites — a Foodand Drug istration review of recalls and reported adverse events. J Food Prot 67:1806-1811.
You’ve probably heard of red wine headaches and the suspected culprit, sulfites. While their reputation as the migraine harbingers isn’t exactly deserved, they can cause other serious problems.
Sulfites prevent browning or discoloration in food love baked goods, condiments, potatoes and shrimp. The chemicals are particularly prevalent in dried fruit love apricots, to preserve the light coloring after drying.
Winemakers also use sulfites to maintain freshness and prevent oxidation. In the ’70s and ’80s, the use of sulfites as food preservatives drastically increased, as did the number of people who began experiencing reactions.
«A sulfite sensitivity is a genuine thing, but it’s not a true allergy,» says Dr. Steve Taylor, director of the Food Allergy Research and Resource Program at the University of Nebraska. «An allergy involves some abnormal response of the immune system, and the immune system is not involved in this at every. It is some form of intolerance.»
Most allergic reactions happen after inhaling the sulfites powdered on foods while eating them.
This can then lead to difficulty breathing or wheezing, but the Food and Drug istration (FDA) says that less than 1% of the population in the United States experiences this sensitivity.
The people most at risk are asthmatics, especially those who use steroid medications. Taylor says that about 5 to 10% of people with asthma will own a sulfite sensitivity, but it’s extremely rare for non-sufferers to experience it. Even 80% of asthmatics with mild symptoms don’t own sulfite sensitivities.
Since 1986, the FDA has become more stringent about sulfites in foods, banning it in unused fruits and vegetables (minus potatoes) as well as salad bars.
For those looking to avoid sulfites, skip snacks with these ingredients:
- Potassium bisulfite
- Sodium metabisulfite
- Sulfur dioxide
- Potassium metabisulfite
- Sodium bisulfite
- Sodium sulfite
As for the oft-cited wine headache, Taylor says there’s no confirmation supporting the link. In fact, wine contains 10 times less sulfites than dried fruits. For those people who own eaten dried fruits and own never had issues, a sulfite sensitivity is most likely not the cause.
If you suspect you might own a sensitivity, Taylor recommends seeing an allergist.
A professional confirmation means you’ll own to give up wine and dried fruit, but there are plenty of other treats that are fair game.
A food allergy is caused by your immune system handling harmless proteins in certain foods as a threat. It releases a number of chemicals, which trigger an allergic reaction.
It’s not completely known how sulfites cause reactions in certain people.
Some people clearly make allergic antibodies against sulfites, while others do not.
The gasses generated from sulfites might cause muscle spasms in the lungs of some asthmatics, or the reaction could be related to the inability of some people to metabolize the sulfites appropriately.