If your alcoholic beverage of choice is a nice glass of red, perfectly paired with a steak dinner, sipped at a winery, or best enjoyed on the couch with your favourite movie, you might also be aware of the dreaded “red wine headache” that can follow.

Striking soon after your last sip rather than coming on the next morning, this headache is something of a mystery to pinot noir lovers — but now we might have a clue as to what causes it.

Researchers think they’ve found out why particularly red wine can bring on such a severe headache. It turns out that a particular ingredient, when broken down by the liver, produces a substance with the same impact as a drug used to treat alcoholism by making people feel terrible if they drink.

Researchers think they might have finally solved the red wine headache. Photo/123rf

Morris Levin, director of the Headache Centre at the University of California in San Francisco, says, “We think we are finally on the right track toward explaining this millennia-old mystery,” reports the Guardian UK.

“The next step is to test it scientifically on people who develop these headaches.”

Red wine headaches can come on as soon as 30 minutes after drinking only one or two modest glasses. Several ingredients in red wine have come under scrutiny over the years — is it the sulphites, the tannins, the biogenic amines or the phenolic flavonoids to blame?

According to the study published in Scientific Reports, researchers looked closely at phenolic flavonoids — compounds that come from grape seeds and skin, which help form red wine’s taste, colour and mouthfeel. Red wines have flavonoid levels up to 10 times higher than those in white wine.

When someone drinks wine, the alcohol is metabolised into acetate. First, the alcohol is converted from ethanol to acetaldehyde, and second, the acetaldehyde turns into acetate, with the whole process orchestrated by particular enzymes in the liver.

Researchers tested more than a dozen red wine compounds, with one in particular standing out. Quercetin, a flavanol found nearly exclusively in red wine, is processed into several substances in the body. One of these, quercetin glucuronide, blocks the enzyme that turns acetaldehyde into acetate.

Those who tend to get migraines are even more susceptible to get a headache after a glass of red. Photo / 123rf

What does this mean for wine drinkers?

It all sounds quite abstract, but this could be the key to solving those mystery headaches.

With that enzyme blocked, scientists believe acetaldehyde builds up in your bloodstream. High levels of this build-up can cause headaches, facial flushing, nausea and even sweating. The drug disulfiram blocks the same enzyme, and is used to treat alcoholics by giving them those exact symptoms when they drink.

It’s not clear why some people are more vulnerable to red wine headaches than others, but the research shows those who tend to get migraines are especially at risk of developing them when they drink red wine with even moderate amounts of quercetin.

The research team’s next step is to conduct a clinical trial using red wines with varying levels of quercetin.

Results from this trial could help people avoid this type of headache.

We know grapes produce quercetin as a response to sunlight — so grapes grown in clusters exposed to the sun, like cabernets from the Napa Valley in the US, can contain five times more quercetin than other varieties. Ageing, skin contact during fermentation, and the fining (clarification) process can also affect quercetin levels.

Levin says it could be “potentially very helpful” for red wine lovers when it comes to choosing a bottle in the wine aisle.

“Also, winemakers may use our findings to reduce quercetin in their wines,” he notes — meaning it might just become easier to avoid the headache in future.