Sulfite sensitivity explained: the wine preservative to watch

A glass of wine, and within minutes a tight chest, a wheeze, a stuffy nose. A handful of dried apricots, and the same. It's easy to put it all down to "the wine" in a vague way - but for some people the reaction is to something very specific carried inside it: sulfites.

Sulfite sensitivity is one of the better-defined food-chemical reactions, with a clear and well-known link to asthma, and the sections below cover how it works.

What sulfites actually are

Sulfites are a family of preservative additives - sulfur dioxide and various sulfite salts such as sodium and potassium metabisulfite.

They're used widely in the food industry to stop browning, prevent oxidation and protect against microbial spoilage.¹ Wine is the classic source, where sulfites guard against oxidation and bacteria.⁴ They also turn up in dried fruit, packaged and dehydrated potato products, bottled lemon and lime juice, pickled foods, some shrimp and a range of processed foods.¹

The active ingredient in all of them is the same: sulfites release sulfur dioxide gas (SO2), and it's that gas that does the preserving. Because reactions are well recognised, sulfites generally have to be declared on labels above a set threshold - the familiar "contains sulfites."

How it differs from a classic allergy

As with histamine and salicylates, the mechanism is worth pinning down first.

A true IgE-mediated allergy to sulfites does exist, and it's documented in only a minority of cases.³ For most people, sulfite sensitivity is a non-allergic reaction with a direct chemical mechanism behind it.

The mechanism is not fully settled

The exact mechanism of sulfite sensitivity isn't fully understood, and researchers describe several plausible routes.¹

The leading one is SO2 gas irritation. In an acidic environment - the mouth, and especially the stomach - sulfites release sulfur dioxide gas. SO2 is a known respiratory irritant, and breathed in or in contact with the airway it can provoke the airways to narrow.² A related idea is a reflex: SO2 stimulating sensory nerves in the airway, which triggers a reflex tightening.¹

A third route is about clearance. The body normally detoxifies sulfite with an enzyme called sulfite oxidase, which converts it into harmless sulfate. Some people - including some people with asthma - appear to have lower sulfite oxidase activity, so they clear sulfite less efficiently.² It's the same capacity story familiar from other intolerances: not enough of the enzyme that's meant to handle the compound.

The asthma connection

The defining feature of sulfite sensitivity is its link to asthma.

The great majority of reported reactions are bronchoconstriction - wheezing, chest tightness, cough - in people who already have asthma. Estimates suggest somewhere around 3 to 10% of people with asthma react to sulfites, with higher rates in those whose asthma is more severe.¹ In other words, sulfite sensitivity is far more a feature of existing asthma than something that appears out of nowhere on its own.

Other reactions are reported too - hives, flushing, a drop in blood pressure, abdominal pain and diarrhoea - and while serious reactions are uncommon, they are documented.¹

Why it varies: dose, acidity and form

Like the other food-chemical sensitivities, this is a threshold effect - and a few specific things move that threshold.

The dose matters: how much sulfite a food or drink actually contains. Acidity matters: a more acidic food releases more SO2 gas, so it tends to provoke more. And the form matters: an acidic liquid like wine releases gas readily, which is part of why wine is such a frequent culprit. On top of that, how well-controlled someone's asthma is on a given day shifts how easily a reaction is triggered. The same sulfite dose can do nothing one day and something the next.

Finding your pattern

Because the reaction is fast and fairly specific, a few things are worth tracking:

• High-sulfite foods and drinks - wine and beer, dried fruit, packaged potato products, pickled foods, bottled citrus juice.
• The type of symptom - chest tightness and wheeze (the airway route) versus skin or gut symptoms.
• The timing - sulfite reactions tend to come on fast, within minutes.
• The context - dose, and how settled your asthma is at the time.

Where Triggerbites fits in

Sulfite sensitivity hides inside foods you'd never group together - wine, dried apricots, a restaurant salad - and that scattered pattern is exactly what tracking is good at surfacing.

You log meals, drinks and symptoms in plain language, and Triggerbites extracts the ingredients, tags compounds like sulfites, and correlates them with your symptoms across time windows - including how dose-dependent a reaction is and how it tracks against the rest of your day. You get the specific pattern in place of a general suspicion about "wine."

It takes seconds a day, and the documented picture it builds is a clear, concrete thing to share with a doctor.

Log your day in 30 seconds

Text, voice or photo. Log as you go, or recap it all in the evening.

Your food, broken down

Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.

Everything in the same journal

Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.

See what repeats over time

Patterns between what you eat and how you feel, including delayed reactions that show up days later.

Triggerbites Features

• Log your day in 30 seconds: Text, voice or photo. Log as you go, or recap it all in the evening.
• Your food, broken down: Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.
• Everything in the same journal: Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.
• See what repeats over time: Patterns between what you eat and how you feel, including delayed reactions that show up days later.

For the related mechanisms, see salicylate sensitivity explained and could it be histamine intolerance?

Live, love, log. 🧡