Sulphites are food preservatives that can cause allergies and other health problems. It’s difficult to know how many sulphites we introduce into our body through the diet because they are added by the food industries to many foods, especially those pre-cooked or ready to eat.
According to the European Community Regulation on Food Additives E numbers from E200 to E297 are assigned to preservatives. In the large family of preservatives sulphites take the numbers from E220 to E228.
E220 is the sulphur dioxide, a gas harmful to health, its derivative products, in the form of salts, are equally harmful because they also release sulphur dioxide:
- E221 Sodium sulphite,
- E222 Sodium hydrogen sulphite,
- E223 Sodium metabisulphite,
- E224 Potassium metabisulphite,
- E225 Potassium sulphite,
- E226 Calcium sulphite,
- E227 Calcium hydrogen sulphite,
- E228 Potassium hydrogen sulphite.
They are sometimes given in food labels with only the E-number instead of the full name.
These food additives are used extensively by the food industries to protect food stuffs from micro-organisms and oxidation. In fact, sulphites are also used as antioxidants to prolong the original pink colour of meat and fish (especially shellfish such as shrimps) making them to appear fresher and more attractive therefore more salable.
We find sulphites especially in wines, where they occur naturally due to the natural fermentation, but they can be added in the form of sulphur dioxide to preserve wines in various stages of wine making. Usually, white wines contain more sulphites than red wines, especially the sweet white wines. We also can find sulphites in dried fruits, fruit juices, beers, in nuts and many other products including pickles, dehydrated mashed potatoes, dressings, breakfast cereals and others.
The most common symptoms that can be felt just a few minutes after the intake of foods or beverages containing sulphites are: breathing difficulty, shortness of breath, wheezing and coughing. People with asthma and/or allergic to acetylsalicylic acid or aspirin should be very careful to not have foods or beverages containing sulphites; these people run the risk of needing immediate emergency treatment, In rare cases and high concentrations sulphites can even be fatal.
In healthy people, but sensitive to these substances, sulphites may cause rash, nausea and chest pain. Out of curiosity, the typical red colouring that appears in the face of some people after drinking wine is due to the presence of sulphites in the wine.
The law requires manufacturers to report the words ‘Contains Sulphites‘ on the label of foods or beverages to which they were added, but only if concentration is higher than 10 mg / l or kg.
In the U.S., the FDA (Food and Drug Administration) estimates that at least one individual in a hundred is sulphite-sensitive. The sensitivity can develop at any time of life, we don’t know yet the minimum threshold necessary to trigger the reaction in susceptible individuals, even because it is different from person to person.