For those who suffer from the dreaded "red wine headache," experts are offering some insights into why it occurs and how to prevent it.
The festive holiday season often includes an increase in red wine consumption — but for some, enjoying even one or two glasses can leave them with a painful, pounding headache that usually begins within 30 minutes to three hours after drinking a glass of the beverage, according to experts.
A flavanol found in red wines could be the culprit behind the headaches, according to a study by University of California, Davis, which was published in the journal Scientific Reports last month.
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The flavanol, called quercetin, is found in grapes and other fruits and vegetables.
It is 10 times more prevalent in red wines than in white wines, the researchers noted.
On its own, it’s considered a healthy antioxidant — but the trouble begins when it’s consumed with alcohol.
"When it gets in your bloodstream, your body converts it to a different form called quercetin glucuronide," said wine chemist and corresponding author Andrew Waterhouse, professor emeritus with the UC Davis Department of Viticulture and Enology, in a press release from the university.
"In that form, it blocks the metabolism of alcohol."
In the study, the scientists used in-vitro laboratory tests to measure the impact of the flavonol on enzymes.
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They found that quercetin blocks the function of ALDH2, the enzyme that metabolizes alcohol. When the alcohol isn’t metabolized, a toxin called acetaldehyde builds up in the system.
"Acetaldehyde is a well-known toxin, irritant and inflammatory substance," said lead author Apramita Devi, postdoctoral researcher with the UC Davis Department of Viticulture and Enology, in the release.
"Researchers know that high levels of acetaldehyde can cause facial flushing, headache and nausea."
So why do some people experience headaches and others don’t?
One of the study authors noted that people who get migraines or are more susceptible to headaches in general are more likely to experience them after drinking red wine.
There is a possibility that some people have enzymes that are more easily inhibited by quercetin, and so are more affected by the buildup of acetaldehyde, the release noted.
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Different red wines can also have different effects, they stated.
"Quercetin is produced by the grapes in response to sunlight," Waterhouse said in the 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."
The levels of the flavonol can also vary depending on how the wine is made and the aging process.
To confirm this theory, the UC Davis researchers are planning a clinical trial with human participants to compare the effects of red wines that contain larger amounts of quercetin to those containing very little of the flavonol.
Fox News Digital reached out to the researchers for additional comment.
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Dr. Ellie Pierson, a scientific manager at food intolerance test specialist YorkTest in the U.K., believes that certain chemicals in red wines, called histamines, can trigger the headaches.
"Histamine is a chemical that occurs naturally in some foods," Pierson said in a statement to Fox News Digital.
"If after eating or drinking, you tend to notice swelling, rashes, sneezing or sickness within 30 minutes, be mindful it could be a histamine intolerance."
In those with histamine sensitivities, consuming only a small amount of red wine can trigger symptoms of a hangover, including nausea, throat itchiness and flushing, she warned.
All alcohols contain some level of histamines, but they are significantly higher in red wine.
Those with sensitivities might consider switching to clear spirits, Pierson recommended.
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Experts also suggested staying hydrated by drinking a glass of water between glasses of wine.
"Many people may be unaware that so many foods contain histamines and could be causing a reaction," she told Fox News Digital. "This is why it’s so important to keep a food diary to track which foods trigger a reaction, as often this type of intolerance is misdiagnosed and is usually mistaken for seasonal or food allergies."
For those who are having a reaction that's worse than normal, Pierson suggested contacting a health care professional or a dietitian who can help create a diet plan around histamine intolerances.
