Q: How widespread is sulfur sensitivity, and what are the symptoms of an allergic reaction to sulfites in wine?—Charley, Monroe, La.
A: Sulfites are one of the most fascinating aspects of wine science. They’re also one of the most misunderstood. For starters, they don’t cause headaches. You can blame biogenic amines, a polyphenol called quercetin, and alcohol itself for those.
Sulfites aren’t the same as sulfates or sulfides. They’re present in much higher quantities in many common food items—including dried fruits, shrimp, bread dough and even maraschino cherries—than in wine. They’re also found in some medicines. Even though they’ve been widely used for their antimicrobial and antioxidant properties since ancient times and are tolerated well by the vast majority of people, they remain a hot topic of controversy among wine lovers and winemakers.
How Many People Have a Sulfur Sensitivity?
That said, there is a very small number of people who have a true allergy or sensitivity to sulfites. The vast majority of these people also have asthma. The medical literature estimates the proportion to range between 0.05 percent and 1 percent of the general population, with around 5 percent of asthmatics reporting sensitivity.
Adult women with asthma are most likely to have a sulfur sensitivity, and some people don’t become sensitive until well into adulthood. If you suspect you may have a sensitivity, an allergist or other physician should be able to perform an oral challenge test to determine whether or not you react.
What Are the Symptoms?
Symptoms, and their severity, can vary widely. The majority of reactions are mild, though severe reactions have been documented. Symptoms often resemble those of asthma and include wheezing, cough and chest tightness. Some people may also experience sneezing, hives, a runny nose or gastrointestinal discomfort.
Many sulfur compounds exist in wine; most of these are dissolved in the liquid, but some SO2 will also be released in gas form. People are allergic to that vapor form of SO2—so if wine gives you issues, it’s likely what you inhale, not what you drink, that’s causing the problem. It’s been speculated that SO2 produced in the stomach after ingesting sulfites can also be inhaled and trigger a reaction.
How much is required to set off a sensitivity? The threshold varies by person, but one paper suggests that 20–50 mg of ingested sulfites may provoke sensitivity. According to Understanding Wine Chemistry, a typical glass of wine contains 10–15 mg of SO2. Again, thresholds vary by person, so you may be OK having a glass or two of wine, even if you have a known sensitivity. But that depends on the wine and on your physiology. According to the Cleveland Clinic, several treatments may help alleviate or prevent a reaction, including antihistamines and vitamin B12.
Can I Still Enjoy Wine?
If you have a sensitivity but still want to enjoy wine, there are many wines made with low or no added sulfur that may be worth exploring. However, know that there’s no such thing as a completely sulfur-free wine. That’s because some sulfites are produced by yeast during alcoholic fermentation. It may also be possible to remove some sulfites by adding hydrogen peroxide, but that’s likely to negatively impact how your wine smells and tastes.
As always, consult your healthcare provider about incorporating wine into a healthy lifestyle.—Kenny Martin
