Are sulfites harmful

Are sulfites harmful?

Pawel Malczewski
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Short Summary

For the general population, sulfites (sulphites) do not cause any side-reactions and are considered safe. However, a small percentage of the population is sulfite-sensitive (mostly a tiny percentage of asthmatics 5-10%) and for them sulfites may cause some mild to severe (rarely) side reactions. For a quick answer click here.

Explanation

What are Sulfites?

Sulfites are chemical compounds, produced in our bodies to process amino-acids that contain sulphur.

Sulfites also occur naturally in some foods, or can be used as an additive to foods or food packaging. Here is a summary of sulfite occurrence: (1)Health Canada. Sulphites – One of the ten priority food allergens. Available here.:

  • Naturally occur in human body;
  • Naturally occur in some foods (e.g. are produced in the process of fermentation of foods);
  • Used as preservatives to
    – prevent discoloration of food,
    – prolong shelf life,
    – prevent growth of microorganisms
  • Used in medications – to maintain its potency;
  • Used in bleaching food starches such as potato starch;
  • Used in production of packaging materials such as cellophane;
  • Used in bottle-sanitizing solutions for home brewing.

These chemical compounds have been used since the 17th Century and were approved in the U.S. in the 1800s. In general, they are regarded as safe with exception of sulfite-sensitive people which are estimated at up to 500,000 people (<0.05% of the population)in the U.S. (2)Lester MR. Sulfite sensitivity: significance in human health. Journal of the American College of Nutrition. Volume 14, Issue 3, 1995. Available here.

Sulfites in wines

Sulfites occur naturally in all wines in varied amounts, and can be also added to prevent from browning and as a preservative.

There is no such thing as 100% sulfite-free wine. Organic wines are lower in sulfites but not completely free from it.

In the United States, to be able to label a wine “organic”, the contents of sulfites must be only naturally occurring and cannot exceed 10 parts per million (ppm). Any wines with more than 10 ppm must have a label stating “Contains Sulfites.” (3)USDA. Guidelines for labeling wine with organic references. Available here.

White wines generally contain more sulfites than red wines. Sweeter wines contain more sulfites than dry ones. (4)Scampicchio M, Lawrence NS, Arecchi A, Mannino S. Determination of Sulfite in Wine by Linear Sweep Voltammetry. Electroanalysis. Volume 20, Issue 4, pages 444–447, February 2008. Available here.

Note: wines contain other additives and symptoms usually attributed to sulfites in wines can have other origins. Many of these additives have been approved and don’t have to be mentioned on the label. (5)Alcohol and tobacco tax and trade bureau. Wine and Juice Treating Materials and Processes for Domestic Wine Production. Available here. (6)Mountain peoples wine distributing, Inc. Wine Additives. Available here.

There are no “sulfates” in wine

Sulfates are often confused with sulfites. Sulfates and sulfites have a different atomic structure and properties and therefore different application in the industry. There are no sulfates in wines or foods such as dried fruit. They don’t occur naturally in wines and they are not added as preservatives.

Sulfate is a compound produced as a result of decaying organic matter such as plants and animals and is also produced by some industrial processes. Sulfates are also released to the environment by mines, pulp mills, tanneries and textile plants. (7)Wisconsin Department of Health Services. Sulfates. Available here.

Foods with sulfites

Sulfites are used in foods as preservatives to prolong their shelf life and to prevent spoilage, microbe growth, browning and discoloration. They are also added to some medications. (8)Cleveland Clinic. Sulfite sensitivity. Available here.

Sulfites are added to some foods, such as:

  • Baked products and pastry especially containing dried fruit;
  • Beers (alcoholic and non-alcoholic);
  • Canned and frozen fruit and vegetables;
  • Cereal products (e.g. cornmeal, crackers and muesli);
  • Ciders (alcoholic and non-alcoholic);
  • Condiments (e.g. ketchup, mustard, vinegar, pickles);
  • Dried fruit (e.g. raisins, shredded coconut, apricots); (read more..)
  • Dried herbs and spices;
  • Fish and seafood;
  • Fresh grapes;
  • Fruit and vegetable juices;
  • Lemon and lime juice concentrates;
  • Noodle and rice mixes;
  • Processed fruit products and fillings (e.g. jams, jellies, marmalade, fruit syrups);
  • Processed potatoes (e.g. frozen french fries);
  • Sauces, salad dressings, packet soups;
  • Shrimps;
  • Soy products;
  • Starches (e.g. corn starch, potato starch);
  • Sugar syrups;
  • Tomato products (e.g. pastes, pulps);
  • Wines (non-organic).

Symptoms of sulfite allergy

Asthmatic adults are the most affected by sulfites, especially women. Between 5% and 10 % of asthmatics may display allergic reactions. Sulfites can be especially dangerous to asthmatics that are steroid-dependent or whose airways are more sensitive and experience stronger reactions to allergens.

The majority of side-effects of sulfites in asthmatics are mild. However, the effects can range from no reaction to severe reaction.

The most common reactions resemble mild asthma symptoms while severe reactions may be anaphylactic and include (9)Health Canada. Sulphites – One of the ten priority food allergens. Available here.:

  • Anxiety, distress;
  • Cramps;
  • Diarrhea;
  • Difficulty breathing, speaking and swallowing due to swelling of the airways, throat and tongue;
  • Flushed face;
  • Loss of consciousness;
  • Lowering blood pressure, rapid heartbeat;
  • Hives;
  • Weakness, faintness, paleness;
  • Wheezing;
  • Swelling of the eyes, face and lips;
  • Vomiting.

It is very rare for non-asthmatics to be sulfite sensitive.

Severe anaphylactic reaction, although not common, may result in death.

In United States any drugs containing sulfites and food products with more than 10 parts per million must be labeled. This law was passed in 1987. (10)Wisconsin Department of Health Services. Sulfates. Available here.

Conclusion

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For most of the population the amounts of sulfites contained in foods are not harmful. A total of 5-10% of asthmatics may be affected and, although most cases are mild, a small percentage may experience severe reactions. Before reaching for a glass of wine, beer or a handful of dried fruits containing sulfites, consult your doctor to examine your medical history and perform the sulfite “challenge” test.

References   [ + ]

1. Health Canada. Sulphites – One of the ten priority food allergens. Available here.
2. Lester MR. Sulfite sensitivity: significance in human health. Journal of the American College of Nutrition. Volume 14, Issue 3, 1995. Available here.
3. USDA. Guidelines for labeling wine with organic references. Available here.
4. Scampicchio M, Lawrence NS, Arecchi A, Mannino S. Determination of Sulfite in Wine by Linear Sweep Voltammetry. Electroanalysis. Volume 20, Issue 4, pages 444–447, February 2008. Available here.
5. Alcohol and tobacco tax and trade bureau. Wine and Juice Treating Materials and Processes for Domestic Wine Production. Available here.
6. Mountain peoples wine distributing, Inc. Wine Additives. Available here.
7. Wisconsin Department of Health Services. Sulfates. Available here.
8. Cleveland Clinic. Sulfite sensitivity. Available here.
9. Health Canada. Sulphites – One of the ten priority food allergens. Available here.
10. Wisconsin Department of Health Services. Sulfates. Available here.

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