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Could a Sulfite Sensitivity Be the Cause of Your Asthma?


Sulfites have been implicated as a cause of asthma symptoms that may range from mild wheezing to potentially life-threatening asthmatic reactions.

Sulfites occur naturally in the human body, from air pollution, and it’s also found in foods.

Sulfite sensitivity is more commonly found in women and it’s even more common in people who’re steroid-dependent asthmatics (aka, those who use steroid inhalers to control their asthma).

If you’re a sulfite-sensitive asthmatic, it’s important to consider the upper limit at which you expose yourself to sulfites through the environment and the foods you consume.

This article will review:

Read on and enlighten yourself about how sulfites may be impacting your asthma.

What’s a Sulfite?

Sulfites have been used since Roman times to preserve food flavor & color, inhibit bacterial growth, reduce spoilage, stop fresh food from spotting and turning brown, and help preserve medications to increase their shelf life.

Sulfites release sulfur dioxide (also known as SO2), which is the active component that helps preserve these foods and medications.

Sulfites in foods are primarily used to prevent browning and discoloration during preparation and storage. Sulfites can also happen naturally in the process of making wine and beer. Additionally, it’s also a common air pollutant in the form of sulfur dioxide (SO2).

Sulfites usually don’t cause problems in people without asthma, even when large amounts are consumed.

However, in about 5 to 10 percent of individuals who suffer from asthma, sulfites are known to increase asthma symptoms like wheezing, chest tightness, and coughing.

Sulfite Verus Sulfate

As I stated, an estimated 5-10% of asthmatics in the U.S. experience asthmatic symptoms stemming from sensitivity to sulfites.

In healthy individuals, sulfite is generally rapidly detoxified into its less-reactive counterpart, sulfate.

Sulfate (as opposed to sulfite) is an anti-inflammatory chemical that is needed for making stomach acid and producing digestive enzymes in our bodies. It also detoxifies chemicals found in foods and drugs.

Sulfite sensitivity is likely due in part to a deficiency of the enzyme sulfite oxidase which converts sulfite into it’s less-reactive counterpart sulfate.

Patients with sulfite-sensitive asthma have been shown to have markedly decreased sulfite oxidase activity. This means more sulfite gets backed up in the body because it can’t be converted into sulfate. This back up eventually leads to asthmatic type reactions as described above.

Those who are sulfite-sensitive may also want to check their B12 and molybdenum levels as deficiencies in these nutrients can also cause a reduced conversion of sulfite into the its less-reactive counterpart sulfate.

Wow, that was quite a mouthful. But hopefully now you’ve got a greater understanding about the difference between sulfate & sulfite and why that matters!

What foods contain a high amount of Sulfites?

Sulfites are most widely known to be used in winemaking, which has been the case for centuries.

These days, sulfites are now added to many other foods during their processing.

However, the U.S. Food and Drug Administration (FDA) has required the presence of added sulfites to be declared on the food label and no longer allows its addition to fresh produce since 1986.

Interestingly, the FDA still permits use of sulfite on processed potatoes. Sulfites must be declared on the label when they are >10ppm SO2.

Of note, sulfites are prohibited from being added to meats as they serve as a good source of Thiamine. Sulfite scavenges this vitamin from foods so it’s been prohibited from adding it to meat products.

Added Sulfites may be identified on a food label as the following:

There are a number of foods that contain sulfites. Here’s a short list to get you started:


Perhaps the most popularly known sulfite containing beverage is wine.

The labeling of the presence of sulfites in alcoholic beverages is under the jurisdiction of the Tax and Trade Bureau (TTB).

Sulfites occur naturally in wine making but are also commonly added to prevent undesirable growth of acid producing bacteria.

Some organic wineries are now creating wine with “no added sulfites”. The winemaker is only allowed to label their wine “sulfite free” when it is <8ppm.

Of note, LaRocca’s red wine contains no sulfites, and their white wine contains only 1 part per million sulfite. Visit for more information.

Other Factors to Consider

Polluted air can be a source of sulfite too.

Levels of sulfite in air are highest around oil, natural gas and coal burning plants. Hydrogen sulfide is as a by-product in the purification of natural gas and refinement of crude oil.

Exposure to sulfur dioxide in the air can lead to broncho-constriction, even in individuals who don’t usually suffer from asthmatic symptoms.

You can find out the content of sulfite in the atmosphere where you live by visiting:

Additionally, you can protect yourself from polluted air by:

Also, take a look at common cleaners you’re using around your house. Often the harmful chemicals in these products can ramp up asthmatic symptoms.

Try switching to cleaning with plain old vinegar instead. You can also choose EWG (Environmental Working Group) approved cleaning products to reduce your asthma flares. Visit for more information.

Bottom line:

Sulfite in air can aggravate your asthma, and should be your first line of defense before eliminating all sulfite foods.

Avoid the highest and moderate containing sulfite foods for additional help in combating your sulfite-sensitive asthma while investigating a potential B12 or molybdenum deficiency.

It’s important to work with someone who’s well-versed in food sensitivities to help you identify your reactive foods that are contributing to your asthma flares.

You can schedule a free health strategy session with me to see how I can help you relieve your asthma symptoms once and for all!