European researchers are close to finding an effective alternative to adding sulfur dioxide to red wine and other foodstuffs, which could make future holiday seasons happier and healthier for millions.

Sulfur dioxide (SO2), often labeled as E220, is used as a preservative for certain dried fruits and in winemaking as an antimicrobial and antioxidant. Most people can tolerate a small amount of SO2 in their food and wine, but for others it can cause allergic reactions or have other side effects such as headaches.

The European Union-funded so2say project believes it may now have identified a combination of two extracts that can be used instead. Both of them occur naturally in wine and could reduce the presence of SO2 by more than 95 percent, say researchers.

Wine containing the new additive has already been tasted in the U.K., Spain and Germany and judged to be as good as reference bottles containing added sulfur. A further batch was bottled in May 2012 and will be opened in January 2013 by the project's nine consortium members. Further tests will follow four months later. If successful, the technical feasibility of the new extract will have been demonstrated and the procedures for its authorization can start.

The main advantage of SO2 is the combination of anti-oxidative activity with its ability to inhibit the "enzymatic browning" of food products – for instance, fresh cut apples. It also acts as a food and wine preservative, preventing microbial growth and oxidation. Furthermore, sulfur dioxide is a natural byproduct of fermentation. Most yeast strains yield 10–20 milligrams per liter of SO2 during fermentation.

However, SO2 and sulfites strongly reduce vitamin B1 uptake. Reduced uptake of this vitamin can lead to several health problems, such as chronic headache and temporary memory loss. Asthmatics are at particular risk. For these patients, an intake of less than 10 mg sulfite might be enough to provoke an asthma attack.

Wine contains other compounds that may cause headaches or breathing difficulties, such as tyramines and histamines, but the finger is most often pointed at sulfites – sometimes unfairly. Most wine-induced headaches are caused by drinking one too many glasses. 

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