What “Contains Sulfites” (or Sulphites) actually means when printed on a bottle of wine? Why some people claim to be allergic to sulfites, or complain that sulfites give them headaches?
What Sulfites are
Sulfites are substances often used as preservatives in dried fruits and other products, but they naturally occur in wines because they are a natural product of the alcoholic fermentation. Any bottle of wine containing over 10 mg/l (10 parts per million) sulfites is required to bear “CONTAINS SULFITES” on the label. In other words, as no wine cannot naturally contain less than 15-20 mg/l sulfites when bottled, all bottles of wine must actually bear that sentence.
This not necessarily means that sulfites are added even if, as a preservative, sulfites can be added to a wine in order to prevent its spoilage or oxidation, and even as a protection from bacteria.
In fact, sulfur dioxide is commonly used in the food industry, partly because of its antibacterial nature! Sulfite levels in wine are actually much lower than those found in the majority of food: sugar, fruit juice, jams, jellies, cookies, crackers, and other common foods contain substantially high levels of sulfites
Allergies and Headache
Although a small number of people actually suffer from sulfite allergies, the majority of us do not. We can eat food containing “hidden” sulfites without developing a rash, itching, or swelling up. Nevertheless, many people point to the label “Contains Sulfites” if a headache follows a pair of red glasses. Sometimes those people prefer white wine instead…
Contrary to popular thought, red wines contain fewer sulfites than white wines, and sweeter wines contain more sulfites than drier ones. Red wines require less sulfur dioxide to protect them, because of the tannins these wines naturally contain. Though sulfites have often been blamed for causing headaches, many people choose to drink whites with higher sulfite levels to avoid headaches! The headaches such people experience when drinking red wine are, therefore, not caused by sulfites, but might be caused by the tannins in red wine, which release serotonin. And high levels of serotonin are known to produce headaches. If tannins are really the issue, think twice the next time you have a bar of chocolate or a cup of tea: these foods are also rich in tannins!
Sulfites abound in the foods we eat daily, from pizza to processed potatoes, yet these foods do not display large “Contains Sulfites” labels. Dried fruit, alone, contains about ten times more sulfites than a glass of red wine. If you consume dried fruit snacks and feel fine afterward, you probably do not have a sulfite allergy, but obviously, if you experience frequent or severe headaches you should talk to your doctor…