Natural or added sulfites are present in every bottle of wine, as well as in many foods. What are sulfites, and do they carry health risks?
If you’ve ever looked closely at a bottle of wine, “Contains Sulfites” is likely to appear somewhere on the label. These two little words have been the subject of some confusion and concern in recent years, especially as people have been paying more attention to what goes into the foods and beverages they consume. “Contains sulfites” has a somewhat scary ring to it, and it makes people wonder if sulfites, as additives, are automatically something bad. Before deciding whether to avoid products containing sulfites, it’s important to understand what sulfites are, what they’re used for, and whether they present any health risks.
Sulfites are naturally-occurring compounds that plants produce to protect themselves from microbial infection. In winemaking, sulfur dioxide (SO2) is also released during fermentation; and traditionally, winemakers add extra sulfur to wine to preserve freshness and prevent spoiling. Both white and red wine contain sulfites, ranging between 20 and 200 parts per million. Even wines with no sulfites added are usually required to have “contains sulfites” on the label, because natural fermentation creates as much or more SO2 than what would have been added by the winemaker.
Are sulfites in wine harmful? Probably not. While 200 parts per million sounds like a lot, it is really a tiny amount compared to some foods, such as dried fruit, which can contain as much as 3,000 parts per million.
But what about the famous “wine headache?” Don’t sulfites have something to do with this common complaint? The wine headache phenomenon has been studied repeatedly, and still no scientific link has been found between sulfites and headaches. And according to these same studies, sulfites cannot be blamed for hangovers, either. "In high doses, sulfites can cause an adverse reaction in asthmatics," cautions Abhijit Adhye, MD, FACP, a board-certified internal medicine physician at St. Joseph Health Medical Group. "Less than 1 percent of the population is estimated to have a specific sensitivity to sulfites. These people may experience rashes, itching or hives, or have trouble breathing. In rare cases, people can go into anaphylactic shock."
The Food and Drug Administration (FDA) has decreed that sulfites are safe, but recommends that they should be avoided by people with asthma, liver or kidney problems. The World Health Organization recommends, for a man of average weight, that sulfite consumption not exceed the equivalent of a third of a bottle of white wine per day.
Besides wine and dried fruits, there are many commercially-prepared foods that typically contain some sulfites. These include processed meats, fish and shellfish, drink and soup mixes, beer and cocktail mixes, baked goods, frozen pizza, jams, sauces and toppings, fruit and vegetable juice, processed grain products and various condiments.
Sulfites are often confused with nitrites (and their close cousins nitrates, both of which are used as preservatives--they're nearly identical, so we'll just refer to nitrites). But sulfites and nitrites are not exactly the same thing, even though both are used to preserve cured meats, where they prevent the growth of bacteria keep meat looking red. These salts are found in jerky, lunch meat, ham and bacon.
Are nitrites harmful? "Nitrites are considered safe, but not especially healthy," says Dr. Adhye. "Most nitrites need to be consumed in huge amounts to be toxic, though multiple studies have found a connection between processed meat consumption and increased risk of colorectal cancer." Moreover, even unprocessed meats cooked over high heat can form nitrosamines, which have also been linked to cancer. One food that is probably best to eat in moderation (or avoid) is bacon. Bacon is especially high in nitrites, and produces high levels of nitrosamines when fried at high temperatures. To reduce the risk, bacon should be cooked slowly at a low temperature.
Given the low risk of sulfites in wine, plus its documented health benefits, it’s probably just fine to indulge in that second glass, says Dr. Adhye. Just go easy on the bacon and pepperoni pizza!
This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.