Mystery of what causes red wine headaches solved

DAVIS, Calif. — Scientists have uncovered the reason why drinking red wine may give you a headache. Research shows that a natural compound, known as a flavanol, found in red wines can disrupt the body’s alcohol metabolism, leading to headaches.

The University of California-Davis team identified this flavonol as quercetin, which is naturally occurring in a variety of fruits and vegetables, including grapes. Quercetin is recognized as a beneficial antioxidant and is even available as a dietary supplement. However, when it interacts with alcohol, it may cause adverse effects.

“When it gets in your bloodstream, your body converts it to a different form called quercetin glucuronide,” says wine chemist and corresponding author Andrew Waterhouse, professor emeritus with the UC Davis Department of Viticulture and Enology. “In that form, it blocks the metabolism of alcohol.”

They also found that different wines had different amounts of the pain-inducing flavanol depending on how much sunlight the grapes had.

“Quercetin is produced by the grapes in response to sunlight,” Waterhouse continues in a university release. “If you grow grapes with the clusters exposed, such as they do in the Napa Valley for their cabernets, you get much higher levels of quercetin. In some cases, it can be four to five times higher.”

(Photo by Maja Petric on Unsplash)

As a result of consuming this flavanol-filled wine people can accumulate a toxin called acetaldehyde which causes painful symptoms.

“Acetaldehyde is a well-known toxin, irritant and inflammatory substance,” explains lead author Apramita Devi, a postdoctoral researcher with the UC Davis Department of Viticulture and Enology.

“Researchers know that high levels of acetaldehyde can cause facial flushing, headache and nausea.”

Typically, a red wine headache can occur within 30 minutes to three hours after drinking as little as a small glass of wine.

“We postulate that when susceptible people consume wine with even modest amounts of quercetin, they develop headaches, particularly if they have a preexisting migraine or another primary headache condition,” adds co-author Morris Levin, professor of neurology and director of the Headache Center at the University of California-San Francisco.

“We think we are finally on the right track toward explaining this millennia-old mystery.  The next step is to test it scientifically on people who develop these headaches, so stay tuned.”

The team plans to conduct human clinical trials to get further answers as there are still many unknowns about the causes of red wine headaches. It’s unclear why some people seem more susceptible to them than others.

Researchers don’t know if the enzymes of people who suffer from red wine headaches are more easily inhibited by quercetin or if they are just more easily affected by the buildup of the toxin acetaldehyde.

The study is published in the journal Scientific Reports.

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South West News Service writer Isobel Williams contributed to this report.

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