A glass of red wine may pair well with a turkey dinner, but drinking even a small amount can cause headaches in some people. The dreaded “red wine headache” can occur between 30 minutes to three hours after consuming as little as a small glass’ worth. In a study published November 20 in the journal Scientific Reports, a team from the University of California, Davis and the University of California, San Francisco reports that they may have found the culprit.
Questioning the quercetin
The team believes that a flavanol found naturally in red wines can interfere with the body’s usual metabolism of alcohol, which may lead to a headache. This flavanol is called quercetin and it is found in multiple types of fruits and vegetables, including grapes. Quercetin is considered a healthy antioxidant and can even be taken as a supplement, but it can become a problem when metabolized alongside alcohol.
“When it gets in your bloodstream, your body converts it to a different form called quercetin glucuronide,” study co-author and UC Davis wine chemist Andrew Waterhouse said in a statement. “In that form, it blocks the metabolism of alcohol.”
The end result is an accumulation of a toxin called acetaldehyde.
“Acetaldehyde is a well-known toxin, irritant and inflammatory substance,” study co-author and UC Davis microbiologist Apramita Devi said in a statement. “Researchers know that high levels of acetaldehyde can cause facial flushing, headache and nausea.”
A medication called disulfiram that is prescribed to patients to help treat alcohol dependence to discourage drinking is known to cause these same symptoms if alcohol is consumed. Disulfiram also makes acetaldehyde from drinking alcohol build up when an enzyme in the body would usually break it down. Roughly 40 percent of the East Asian population also has alcohol metabolizing enzymes that allows for acetaldehyde to build up in their system.
“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,” study co-author and University of California, San Francisco neurologist Morris Levin said in a statement. “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.”
Turn the lights down
According to the team, sunlight increases the headache-causing flavanol in the grapes grown to make wine.
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“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,” said Waterhouse.
Levels of quercetin can differ depending on how the wine is made, including skin contact during fermentation, the fining processes, and even aging.
The study cautions that there are still many unknowns about the causes of red wine headaches. While we have a better understanding of the biological processes behind red wine headaches, it is still a mystery why some people remain more susceptible to them than others. The team is working on comparing red wines that have a lot of quercetin like shiraz with those that do not have as much to test their theory that quercetin is truly behind red wine headaches on people. They are also curious if the enzymes of people who get red wine headaches often are more easily inhibited by the flavanol or if this group is more easily affected by the buildup of the toxin acetaldehyde.
“If our hypothesis pans out, then we will have the tools to start addressing these important questions,” Waterhouse said.