Sulfites Did Not Give You That Headache (Probably)

foundations

Apr 2

You have seen it on every bottle. That small, slightly ominous line on the back label: "Contains Sulfites."

For a lot of wine drinkers, those two words have become shorthand for "here comes the headache." But the science tells a different story, and it is one worth knowing before you blame the wrong culprit.

So What Actually Are Sulfites?

Sulfites are a group of compounds containing sulfur dioxide (SO2). They have been used as preservatives in food and drink for centuries, and in wine they do two important jobs: they prevent oxidation and they inhibit microbial growth. Without them, a lot of bottles would taste like vinegar long before they reached your glass.

Here is the part that surprises most people: sulfites occur naturally in all wines as a byproduct of fermentation. There is no such thing as a completely sulfite-free wine. Winemakers often add extra sulfur dioxide on top of what fermentation produces, but the idea that sulfites are some foreign chemical being sneaked into your bottle is not quite right. They are part of how wine works.

Why Does the Label Say That Then?

In the United States, wines that contain 10 or more parts per million of sulfites must state on the label that they contain sulfites. This rule applies to both imported and domestic wines. That threshold is low enough that nearly every wine triggers it, which is why you see it everywhere. It is a disclosure requirement, not a danger warning.

Fun Facts

Organic wine in the U.S. cannot have added sulfites, but it still contains naturally occurring ones from fermentation. "No added sulfites" and "sulfite free" are not the same thing.
The "contains sulfites" label requirement in the U.S. dates to 1987, after a small number of severe reactions in people with asthma prompted the FDA to act.
A bottle of white wine may have up to 150 parts per million of sulfites, while dried apricots can have over 2,000 ppm. Your trail mix is working harder than your Chardonnay.
Burning sulfur candles inside wine barrels is one of the oldest preservation techniques in the world. Romans were doing it.

The Headache Question

Here is where it gets interesting. Sulfites have become the go-to scapegoat for wine headaches, and the reputation has stuck hard. But consider this: white wines usually have more sulfites than red wines, yet red wine headaches are more commonly reported. If sulfites were really the main culprit, white wine drinkers would be suffering more than anyone. They are not.

Dried fruits have about 10 times more sulfites than wine. If you can eat a handful of dried apricots without consequence but blame your Cabernet for a headache, sulfites are probably not your problem.

So what actually is? A few more likely candidates:

Histamines. Research points to a group of compounds called biogenic amines, particularly histamine, as a more likely cause of reactions. Histamine is produced when microbes remove carbon dioxide from amino acids during fermentation, and it is present in higher levels in red wine due to longer fermentation and aging.

Tannins. Tannins, found in the skins, seeds, and stems of grapes, can trigger headaches in some people by releasing serotonin, a neurotransmitter that can cause blood vessels to constrict.

Alcohol itself. It is a vasodilator and a diuretic. It expands blood vessels and pulls water out of your body. Dehydration is one of the most straightforward causes of headaches, and wine delivers it efficiently if you are not also drinking water.

Who Actually Needs to Watch Out for Sulfites?

The FDA estimates that fewer than 1% of the general population have sulfite sensitivity. People with this sensitivity can experience various symptoms after consuming sulfites, including breathing difficulties, swelling, nausea, and abdominal cramping. Notably, headaches are not the primary symptom. Respiratory issues are. If you have asthma, it is worth paying attention to your sulfite intake. For most everyone else, the "contains sulfites" label is not something to worry about.

What About Natural Wine and No Added Sulfites?

This is where it gets a little ironic. A recent research paper argues that wines made without added sulfites might actually be more likely to generate symptoms like headaches, because lower sulfite levels allow biogenic amines like histamine to develop more freely during fermentation. In other words, the bottle marketed as the gentler, more natural option could be the one giving you trouble.