What are Sulfites and Why are They Used?
Sulfites are inorganic salts derived from sulfur dioxide ($SO_2$). They have been used for centuries as a food preservative and antioxidant to prevent spoilage and maintain the fresh appearance of foods. Sulfites inhibit the growth of bacteria and molds, and prevent oxidation, which can cause discoloration. They occur naturally in fermented products like wine and beer, but are also widely added to processed foods.
For most people, consuming sulfites poses no health risk. However, a small percentage of the population, particularly those with asthma, may be sensitive. Reactions can range from mild discomfort to severe, allergy-like symptoms.
Foods and Drinks High in Sulfites
Identifying and avoiding high-sulfite foods is the primary management strategy for sensitive individuals. The following categories contain some of the most common sources of high sulfite content:
Dried and Processed Fruits and Vegetables
Dried fruit, in particular, is a notoriously high source of sulfites, as the chemical is used to prevent browning and preserve color.
- Dried apricots: Often treated with sulfur dioxide to maintain their bright orange color.
- Dried raisins and prunes: Many commercially available varieties contain added sulfites.
- Maraschino and glacé cherries: The vibrant red color is often maintained with sulfite additives.
- Dried potatoes and instant mashed potatoes: Used to prevent discoloration in potato products.
Alcoholic and Non-Alcoholic Beverages
Beverages represent another major source of sulfites, both naturally occurring and added.
- Wine: Sulfites are a natural byproduct of fermentation but are also added to preserve flavor and prevent oxidation. Commercially produced wines often have higher levels.
- Beer and cider: Contain sulfites, which can be naturally occurring or added during the brewing process.
- Bottled lemon and lime juices: Concentrates and bottled juices often rely on sulfites for preservation.
- Grape juice: May contain sulfites, depending on processing.
Processed Meats and Seafood
Sulfites are used in some meats and seafood to inhibit bacterial growth and prevent discoloration, particularly in restaurant or market preparations.
- Sausages and hot dogs: Processed meat products can contain sulfites.
- Deli meats: Some pre-sliced deli meats may be treated.
- Prawns and shrimp: Fresh or frozen shellfish may be treated to prevent black spots.
Condiments and Sauces
Many shelf-stable condiments and prepared food products use sulfites as a preservative.
- Vinegar and wine vinegar: Common sources of sulfites.
- Guacamole and sauces: Prepared guacamole often contains sulfites to prevent browning, and many packaged sauces and gravies do as well.
- Pickled foods: Sauerkraut, relishes, and other pickled vegetables can contain sulfites.
Other Sources
- Soy products: Tofu and certain soy products can contain sulfites.
- Molasses and fruit syrups: These can contain added sulfites.
- Baked goods: Some pie crusts, pizza doughs, and cookies may contain sulfites.
Comparison of Common High-Sulfite Foods with Low-Sulfite Alternatives
| Food Category | High-Sulfite Examples | Low/No-Sulfite Alternatives |
|---|---|---|
| Dried Fruit | Dried apricots, raisins, prunes | Fresh fruit, freeze-dried fruit, sun-dried fruit without sulfur dioxide |
| Beverages | Commercial wine, bottled lemon/lime juice | Organic wine (often lower in sulfites), fresh-squeezed juice, herbal tea |
| Potatoes | Frozen French fries, instant mashed potatoes | Fresh potatoes, homemade potato dishes |
| Meats | Processed sausage, deli meats | Fresh, unprocessed cuts of meat or poultry |
| Condiments | Wine vinegar, store-bought salad dressings | Apple cider vinegar, homemade vinaigrettes |
Managing a Low-Sulfite Diet
For those sensitive to sulfites, managing intake is about being aware and reading labels. In many countries, including the U.S. and Canada, regulations require sulfites to be declared on food labels if they exceed certain levels. Look for names such as:
- Potassium bisulfite
- Potassium metabisulfite
- Sodium bisulfite
- Sodium metabisulfite
- Sodium sulfite
- Sulfur dioxide
When dining out, especially at salad bars or seafood restaurants, be mindful that sulfites may be used to keep produce fresh or prevent seafood from browning. A low-sulfite diet focuses on whole, unprocessed foods, fresh fruits and vegetables, and meat without additives. Cooking at home from scratch is the most reliable way to control sulfite content in your meals.
Conclusion
For individuals with sulfite sensitivity, knowing what foods are high in sulfites is a critical step in managing symptoms and maintaining a healthy diet. Sulfites act as effective preservatives in a wide array of processed foods and beverages, from dried fruits and wines to processed meats and condiments. By carefully reading food labels and prioritizing fresh, whole foods, those with sensitivities can effectively control their sulfite intake and improve their overall well-being. Consulting a healthcare professional or registered dietitian is always recommended for personalized dietary advice, especially if symptoms persist. More information on sulfite sensitivity can be found at the Australasian Society of Clinical Immunology and Allergy website.
