Enlarge / Red wine headache (RWH) might be caused by quercetin, which inhibits an enzyme that processes acetaldehyde in the blood. (credit: Mick Stephenson/CC BY-SA 3.0)

As the holiday season kicks off this week, many will be making a consequential choice at dinner: red wine or white wine? And if your choice is red, will you be risking a headache? The fact that red wine can sometimes cause headaches in certain individuals (especially those prone to migraines) is common knowledge—so much so that the phenomenon (“RWH”) even has its own Wikipedia page. The Roman encyclopedist Celsus wrote in his treatise De Medicina about the pain felt after drinking wine, while six centuries later, Paul of Aegina mentioned that drinking wine could trigger a headache.

But the science to date is largely unclear regarding which components of red wine are responsible, as well as the mechanisms behind the phenomenon. A team of California scientists has narrowed down the likely culprits to a flavonol called quercetin, according to a new paper published in the journal Scientific Reports, although they have yet to run experiments with participants prone to RWH to test their hypothesis.

It’s a knotty issue because of the complexities of both wine and human genetics/physiology. Wine is basically water and alcohol, along with acids, dissolved sugars, and other compounds that lend color and flavor. For instance, the tannins in wine are polyphenolic compounds responsible for much of the bitterness and astringency in a given wine; they’re derived from the skins and stems of the grapes, or as a result of aging in oak barrels.