What Causes Red Wine Headaches? A Wine Chemist May Finally Know

For many, wine is a way to kick back and relax after a long day. But for some, wine — and red wine in particular — can be a pain, literally.

Some people develop headaches shortly after ingesting wine, often within 30 minutes to three hours after consuming it, no matter how much they pour themselves. The phenomenon is common enough it’s earned itself a title: red wine headache, or RWH.

It’s not just red wine that causes headaches. According to an oft-cited 2008 review paper, about one-third of participants reported headaches triggered by alcohol. But for whatever reason, red wine seems to be the most popular headache inducer. Despite the fact that the red wine headache has been known about for decades, researchers are still debating the exact cause of the malady. But a recent study published in Scientific Reports introduces a new potential player that might be responsible for the aches.

What’s in red wine that could cause headaches?

For some time, researchers and consumers alike largely attributed red wine headaches to sulfites. These compounds are used as preservatives in wine and are advertised on the bottle, making them an easy thing for consumers to blame. However, in recent years, experts have largely debunked this theory, as white wine actually tends to have more sulfites than red wine.

Other products found in red wine that have been pegged to headaches include phenolics, biogenic amines, and tannins. Phenolics, for example, are chemical compounds that contribute to the wine’s taste, feel, and color. They are present in larger quantities in red wine compared to white, which makes them an easy culprit. But no one could nail down a mechanism for how they could cause headaches. Not to mention, other foods high in phenolics don’t seem to cause headaches.

One of the most recent studies on this topic, conducted by a pair of chemists at the University of California, Davis, and a neurologist at UCSF, suggests a different compound might be to blame: quercetin-3-glucoronid. Quercetin belongs to a class of molecules called flavonols, which are found in all sorts of fruits and veggies –– grapes included. On its own, it doesn’t cause trouble, but when it mixes with alcohol, it can impact the way your body processes the alcohol.

When you drink wine (or any beverage containing alcohol), you metabolize the alcohol in two steps, Andrew Waterhouse, a wine chemist and one of the study’s authors, tells Inverse. First, the body converts the alcohol to a compound called acetaldehyde, which itself is chemically reactive and can cause inflammation, among other things. Then there’s a second step, where that somewhat toxic chemical is converted to acetate, which is much more palatable to the human body.

The key ingredient for this important chemical process is an enzyme called acetaldehyde dehyrdogenase. While most people have a functioning enzyme, about 8 percent of the world's population has a faulty version of the gene that encodes the protein. Because those with the mutation can’t break down the acetaldehyde as efficiently, it will build up — causing flushing, nausea, and sometimes, headaches. The researchers propose that the enzyme and the lack of efficient breakdown could be to blame for the headaches in red wine.

Waterhouse and his team hypothesized that maybe there was something more abundant in red wine that was the “magic inhibitor” of the enzyme, keeping it from doing its job of breaking down the alcohol. They tested a number of different compounds and found that the quercetin-3-glucuronide, which is derived from the various forms of quercetin in red wine, was a fantastic inhibitor. When the compound was present, there were higher levels of acetaldehyde. Because the compound is already associated with inflammation and irritation, the authors argue that this subsequent build-up could be what’s responsible for those nasty headaches.

This work was conducted in a test tube, so more research will be needed to see if it holds true when it comes to humans drinking actual wine out of a bottle. A small human clinical trial is in the works at UCSF to fully test out whether quercetin leads to more headaches in people.

One issue with studying this compound, Waterhouse says, is that the amount of quercetin varies tremendously in wines, primarily because the level of sunlight affects the quercetin production of the grape. Lower-quality wines tend to have less quercetin because they’re grown in a vineyard with large vines, which prevent each grape from getting a sufficient blast of sunlight.

This could also explain why people who buy “lower quality” wines don’t report as many headaches.

“Let’s not rush out and start changing production,” he says, “but if it is established, there are a couple of things we could do.” Waterhouse notes that there could potentially be a way to remove quercetin from the wine, though that’s not as straightforward as it sounds.

He also hopes that the findings could have implications for other fields, especially headache pain management, though more work is needed in that area.

Hopefully, one day, we may have a better solution than the tried-and-true one so many of us must still swear by. Water and ibuprofen.