What Are Sulfites—and Should You Avoid Sulfite-Rich Foods?

While they’re often (wrongly) blamed for your wine headaches and hangovers, sulfites are just found in vino. In fact, you can find sulfites in a plethora of food products, both naturally and as an additive. We often vilify this particular compound, but are we being unfair or have we been misled? What exactly are sulfites, and should we all be trying to avoid them at all costs? Time to dig into the truth on this common food and drink preservative.

What Exactly Are Sulfites?

“Sulfites are chemical compounds that contain a sulfur ion,” explains Amy Davis, RD, LDN, registered dietitian at FRESH Communications. Sulfites occur naturally in some foods, but are more commonly utilized as food additives, thanks to their preservative properties that help prevent unwanted bacterial growth. Sulfites also help prevent browning in food products exposed to oxygen (oxidation).

Sulfites vs. Sulfates

You’ve probably also heard of sulfates and confused them for one another. While sulfates are also sulfur-based, hence the very similar spelling, you typically won’t find these compounds in food. 

“Sulfates are synthetic sulfur-based chemicals that are typically found in cleaning and personal care products,” Davis says, including shampoos, body washes, skincare products, laundry detergents, and others.

Are Sulfites Safe, or Are They Bad for You?

Sulfites have gotten their fair share of negative health press over the years, but are they really that bad for you? 

“Sulfites are considered safe for most people in normal amounts, but there are currently no particular health benefits associated with them,” Davis says. This stands true for both natural sources of sulfites and the variety of sulfite-based food additives which are generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (USDA).

Issues with sulfites arise when someone has an allergy or sensitivity to the compound. Those who fall within this category typically have a negative reaction of some kind after eating foods rich in sulfites. “Effects may include headaches, skin rashes, swelling, stomach pain, and diarrhea. Individuals with asthma seem to be especially sensitive to sulfites,” says Davis. In fact, studies suggest that 3 to 10% of people with asthma also have a sensitivity to sulfites.

There are also some other general health impacts related to sulfites worth noting. For example, sulfites are not typically added to meat products because they scavenge vitamin B1 before we can absorb the micronutrient. Additionally, a 2017 study found sulfites to inhibit the growth of four beneficial gut bacteria species, even with small amounts. This effect could likely be mitigated by consuming probiotic-rich foods (or a probiotic supplement), but still may deter gut-health-conscious folks, even those without sulfite sensitivities.

Common Foods With Sulfites

Foods That Naturally Contain Sulfites

Ironically, many of the foods that are naturally rich in sulfites are also rich in probiotics, such as fermented foods like sauerkraut and kimchi. This is because sulfites are a natural byproduct of fermentation.

“You can also find naturally occurring sulfites in foods like black tea, peanuts, and even some vegetables like onions, lettuce, garlic, cabbage, kale, asparagus, leeks, chives, and broccoli,” Davis says. Plums, coconuts, strawberries, eggs, maple syrup, soy, and salmon are also natural sources of sulfites.

Foods With Added Sulfites

The list is even longer when it comes to processed foods with sulfites added to them. Wine is the classic example—although wine is also a natural source of sulfites, too, as the skins of grapes naturally contain sulfites, and wine is a fermented product. 

Otherwise, you can commonly find sulfites in plenty of packaged food options, including “juice, sodas, jams, jellies, and pickled vegetables,” Davis says. They may also be in canned vegetables, baked goods, soup or gravy mixes, dried fruit, snack foods like trail mix or chips, pre-peeled potatoes, some brands of shrimp, frozen fruit or veggies, and even molasses.

Should You Avoid Sulfites?

While most people don't experience adverse reactions after eating sulfites, some people try to avoid this compound altogether.

Limiting processed food intake, especially ultra-processed options, is always a smart idea, regardless of its sulfite content. However, it’s a little more convoluted when it comes to natural sulfite sources.

In my professional opinion, if you don’t have a negative reaction to them, the health benefits of natural sulfite sources—fruits, veggies, and protein options including eggs and salmon—far outweigh the minor health disadvantages associated with this compound.

Mindful Ways to Avoid Sulfites

For anyone who wants to eliminate sulfites due to a sensitivity or allergy, the most obvious way is simply to “decrease their intake of foods that are typically high in sulfites,” Davis says. This could be opting for low-sulfite or no-added-sulfite wines (Avaline, Bonterra, Terramore, or Frey Vineyards are a few good options). Some also say that red wine tends to be lower in sulfites than white wines, though there isn’t enough research to substantiate this claim (however it’s certainly worth trying an at-home experiment to see if it makes a difference, if you’re not allergic).

Looking more closely at ingredient lists is also important—the only way to know if a food product contains sulfites is to scour the ingredients list. There are many different types of sulfite additives, but the most common ones include: potassium bisulfite, sulfur dioxide, sodium bisulfite, sodium sulfite, potassium metabisulfite, and sodium metabisulfite.

And if you absolutely must avoid even the healthiest sulfite-containing foods due to health concerns, it can be helpful to write up a list of the most common culprits and post that on your fridge or somewhere in the kitchen. This can help you avoid accidentally eating a sulfite-rich food and serves as a good reminder when writing up grocery lists.

While some processed foods high in sulfites will be hard to find swaps for, more and more alternatives are making their way onto grocery stores shelves (though again, this will require some label reading). Alternatively, you could try your hand at making some typically sulfite-added foods at home: jams, pickled veggies, baked goods, gravy, and trail mix, for example.

The Bottom Line on Sulfites

While sulfites may not be a major health concern for everyone, they can cause unpleasant reactions for those with allergies or sensitivities. Additionally, some emerging research has found that sulfites may impact vitamin B1 absorption and gut microbiome health, potentially encouraging even those without allergies to cut down on their intake. Regardless of the reason, there are plenty of ways to reduce daily sulfite intake, including a basic understanding of natural sources and closely reading food labels.