What are sulfites?

Technically sulfites are compounds that contains a sulfite ion, which is composed of a sulfur atom bound to three oxygen atoms. They are commonly combined with sodium or potassium and used as preservatives. They are used in a wide range of food and drinks to prevent spoilage (e.g., in processed foods), prevent food from browning (e.g., in dried fruits), and to prevent growth of undesirable microorganisms during fermentation or to halt fermentation (e.g., in wine). At Natural Grocers we don’t carry any food products with added sulfites, and we carry only organic and biodynamic wines, which contain significantly lower amounts of sulfites. (For more information about organic and biodynamic wine see the Customer Literature File “Wine”)   

What’s wrong with sulfites?

In some people sulfites cause symptoms such as wheezing, chest tightness, coughing, extreme shortness of breath, flushing, itching, hives, contact dermatitis, eye swelling, nausea, diarrhea, and, in extreme cases, loss of consciousness and anaphylactic shock.ⁱ  Asthmatics seem to be especially susceptible, and between 3% and 10% of asthmatics are believed to be sensitive to sulfites.ⁱⁱ Persons with no history of asthma can also be sensitive, although the actual percentage of these individuals is unknown.

Sulfites may also cause problems outside of the symptoms listed above. In vitro, beneficial bacterial strains were killed or inhibited when exposed to sulfites in concentrations that are well within the range someone eating a standard American diet would be exposed to.ⁱⁱⁱ There is also some research to suggest that sulfites may interfere with glutathione, one of the body’s most important free radical scavengers and an important detoxification agent.^{iv v} While these studies alone are not enough to establish firm conclusions, they do suggest that more research is needed to determine the safety of sulfites as food additives.    

Where are they found?

Because sulfites can cause such severe reactions, the Food and Drug Administration requires that any food containing sulfites with 10 parts per million (ppm) or more must declare their presence in the ingredients list. Terms that indicate sulfites include: sulfur dioxide, sodium sulfite, sodium hydrogen sulfite, sodium metabisulfite, potassium metabisulfite, calcium sulfite, calcium hydrogen sulfite, and potassium hydrogen sulfite.^vi Because alcoholic drinks don’t require ingredient lists, the Alcohol and Tobacco Tax and Trade Bureau (TBB) instead requires a sulfite declaration (such as “Contains Sulfites”) on the label of any alcoholic drink with sulfite levels at or above 10 ppm.ⁱⁱ 

Sulfites naturally occur in some foods, such as fermented foods (sauerkraut, kimchi, etc.), wine and wine vinegars, and even some vegetables, but generally these levels are very low and of less concern. It is the sulfites that are added to foods and drinks that raise the most concern. Dried fruits, commercially peeled and/or prepared potatoes, maraschino cherries, some juices (such as grape, lemon, and lime), shrimp, jams/jellies and pickles/relish are a short list of foods that may contain added sulfites in ranges from less than 10 ppm to over 1,000 ppm.^{vi vii} Remember that sulfites are a food additive and not all manufacturers use sulfites in the production of the listed foods. To know if a product contains sulfites, be sure to read the ingredient list. And you can always know your food is free from added sulfites when you shop at Natural Grocers because we don’t sell any foods that contain added sulfites.    

Sulfites and Wine

When yeasts eat the sugar in grapes to create carbon dioxide and alcohol, a small amount of sulfur dioxide is also produced. Although sulfur dioxide is not technically a sulfite, it is a closely related chemical that must also be labeled as a sulfite. Therefore, all wines contain at least a small amount of sulfites.^viii Sulfites are also commonly added to wine as a preservative and to protect the color. In the U.S., conventional wines are permitted to contain up to 350 ppm. Although sulfite levels in wine can vary greatly depending on the wine’s acidity, sugar level, color, temperature, and growing conditions, the average glass of conventional red wine contains 70 ppm, while the average glass of conventional white contains 122 ppm.^{ix x} Wines that are certified USDA Organic do not have any added sulfites, although, if they contain 10 ppm or more naturally occurring sulfites, the label is still required to say “Contains Sulfites”. If, however, an organic wine contains sulfites in less than 10 ppm, the label may state “Sulfite Free”.  Wines not certified 100% organic but made with organic grapes and biodynamic wines can contain some added sulfites, up to 100 ppm.^xi Organic wine, wine made with organic grapes, and biodynamic wine generally have significantly lower levels of sulfites than their conventional counterparts, with producers reporting lower than 30 ppm on average.^xii

Does Sulfite Cause Headache?

Sulfites are often blamed for the dreaded wine headache some people experience after drinking even a little wine, but in most cases, sulfites probably aren’t the culprit. While it is certainly possible for sulfite-sensitive individuals to develop a headache, the most common symptoms of sulfite sensitivity are allergy-related, like facial flushing, hives, wheezing, etc. Besides, many people who get wine headaches get them from red wine, but not white wine, which almost always contains higher levels of sulfites than red. If someone is sulfite-sensitive, they will experience similar symptoms after eating many of the sulfite-containing foods listed above. 

This is not to say a wine headache isn’t real. There are many possible reasons other than sulfites why people might react poorly to wine. Red wine is particularly high in phenolic flavonoids, owing to the fact that the skin, which is high in these compounds, is used to make red wine and gives wine its color, mouthfeel and taste.^xiii While these compounds are responsible for many of the health benefits of red wine, in some people they can cause headaches.^xiv Another possible culprit is histamines, which tend to be higher in red wines. Some people lack the ability to break down histamines and can experience symptoms when they ingest high amounts.^{xv xiii}  People who are histamine-sensitive would also react to aged cheeses, cured meats and fermented foods, such as sauerkraut. (See the Customer Literature File “Histamine Intolerance” for more information.) Still other possible explanations exist, such as a sensitivity to the amino acid tyramine; sugar added to cheaper wines, which produces a less pure kind of alcohol; or even just plain old, alcohol-induced dehydration.^xvi

One would think that as long as humans have been drinking wine we would know more about this phenomenon, but researchers have yet to reach a conclusion. Until then, if you are one who suffers from wine headaches and you aren’t ready to give up your wine, pay attention to which varieties of wine or growing regions work for you and try to stick to those varieties and/or regions. In general, organic wines, biodynamic wines and wines made with organic grapes will be lower in pesticides and synthetic chemicals, as well as sulfites, so they may also be a good place to start. 

References Available Upon Request