Humans produce about 1,000 milligrams of sulfites each day, but sulfites are also used as a food presevative for several foods, including wine and dried fruit. The U.S. Food and Drug Administration classifies sulfites as "generally recommended as safe," or GRAS, though a small number of people can have a sulfite sensitivity. In general, sulfites have no appreciable impact on your health and only pose a health risk if you're sensitive.
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Sulfites, when used as a preservative, are inorganic salts that help extend the shelf life of certain foods. The salts are used to keep foods from turning brown, to prevent the growth of bacteria and to help maintain the stability of certain medications. Sulfites also occur naturally as part of the fermentation process in foods such as beer and wine.
A small number of people have a sensitivity to sulfites, and the reactions to the sulfites can cause a range of symptoms. These symptoms occur in people who have asthma, and it's far less common for those without asthma to have a sulfite sensitivity. People deficient in sulfite oxidase, the enzyme necessary to break down sulfites, can experience symptoms without having asthma.
Range of Symptoms
Symptoms of a sulfite sensitivity generally occur within 15 to 30 minutes after consuming sulfites. Skin changes and difficulty breathing are common, and nausea, abdominal cramping and diarrhea might also occur. You might also experience changes in your heart rate or serious breathing problems that require immediate medical attention. Many people claim that sulfites cause them to get headaches, but this hasn't been supported by credible research, notes Andrew L. Waterhouse, writing for the University of California Davis.
Reading labels on food and drinks that can contain sulfites is necessary if you have a sensitivity. Wine, for example, that contains sulfites must list that on the label, notes Liza Gross writing for "Wines and Vines." Also, look at the ingredient list for sulfur dioxide, potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium metabisulfite or sodium sulfite, all of which indicate the presence of sulfites.