Scientists say mystery behind red wine headaches could be solved | Culinary science

For the Greek philosopher Celsus, wine was the answer to countless ailments, from fatigue and fever to coughs and constipation. But despite its practical curative powers, grapes, he conceded to his loyal readers, could cause strange headaches.

Now, researchers think they have figured out why wine – red wine in particular – causes such rapid and undeserved headaches. When the liver breaks down a particular ingredient, it produces a substance that has the same effects as a drug used to make alcoholics feel bad if they drink.

“We think we are finally on the right track to explaining this millennia-old mystery,” said Morris Levin, director of the Headache Center at the University of California, San Francisco. “The next step is to test it scientifically on people who develop these headaches. »

Red wine headaches are a different beast than the hangover variety that set in the morning after the day before. Rather than appearing after a long session, they may strike 30 minutes after drinking just one or two small drinks.

Since the time of Celsus, researchers have studied all sorts of compounds in red wine in their search for the culprit. Tannins, sulfites, phenolic flavonoids and biogenic amines are all suspect. So far, none have been identified as a clear trigger.

Write in Scientific reports, US researchers said they looked at phenolic flavonoids, compounds derived from grape seeds and skins that contribute to the color, taste and mouthfeel of red wine. Flavonoid levels can be 10 times higher in red wines than in white wines, making them prime candidates for causing immediate headaches.

When people drink wine, the alcohol is metabolized to acetate in two steps. The first converts alcohol in the form of ethanol into acetaldehyde. The second transforms acetaldehyde into acetate. Specific liver enzymes orchestrate each of these processes.

The researchers, including Professor Andrew Waterhouse, a viticulture expert at the University of California, Davis, conducted laboratory tests on more than a dozen compounds found in red wine. One of them stood out. A flavanol called quercetin, found almost exclusively in red wine, is transformed in the body into various substances. One of them, quercetin glucuronide, has been shown to be particularly effective in blocking the enzyme that converts acetaldehyde to acetate.

This could be the key to solving the mystery. With the suppression of this crucial enzyme, toxic acetaldehyde builds up in the bloodstream, scientists believe. At high levels, it causes headaches, nausea, facial flushing, and sweating. In fact, a drug called disulfiram blocks the same enzyme and is used to treat alcoholics by producing the same miserable symptoms if they drink.

According to researchers, when sensitive people drink red wine containing even modest amounts of quercetin, they may develop headaches, especially if they are prone to migraines. It’s unclear why some are affected more than others: their enzymes may be easier to block, or they may simply be more sensitive to toxic acetaldehyde.

The team now hopes to test the theory with a clinical trial investigating the headache-inducing effects of red wines containing different levels of quercetin. The findings could help people avoid red wine headaches in the future. Grapes produce quercetin in response to sunlight, so grapes grown in exposed clusters, like Napa Valley cabernets, can contain five times more quercetin than other reds. Skin contact during fermentation, fining processes, and aging also affect quercetin levels.

“It will potentially be very helpful for people who drink red wine to be able to choose wines that are less likely to cause headaches,” Levin said. “In addition, winemakers can use our results to reduce quercetin in their wines.”