Researchers Identify the Source of Red Wine Headaches, but It Isn't Sulfites
If you've ever had a night of indulging in red wine, you're likely familiar with the infamous red wine headaches that sometimes follow. But, the chemical source of red wine headaches, a flavor compound called quercetin glucuronide, is something few expected.
Compounds like sulfites, biogenic amines, and tannin have all been popular past scapegoats of the source of red wine headaches.
Andrew L. Waterhouse, Ph.D., a professor of eonology, and post-doc researcher Apramita Devi, are chemists specializing in winemaking at University of California, Davis, who sought to figure out the source of these red wine headaches. As they shared with Science Alert, some people experience flushed skin when drinking alcohol. The flushing is accompanied by a headache, which is caused by a lagging metabolic step as the body breaks down the booze.
Alcohol is broken down into two steps: first into acetaldehyde, then into acetate by an enzyme called ALDH. The second step is slower for individuals who experience flushed skin because their ALDH is less efficient.
This also leads to a buildup of acetaldehyde, which has been linked to hangovers.
Waterhouse and Devi scanned the list of abundant phenolics in red wine to understand what could inhibit ALDH, slowing down the second metabolic step, leading to the headaches.
To put the enzymes to the test, they set up an inhibition assay in test tubes and measured how quickly the enzyme ALDH breaks down acetaldehyde. Then, they added the suspected inhibitors, which included quercetin glucuronide and other common phenolics.
While other phenolics had varying effects, the tests confirmed quercetin glucuronide to be the headache culprit, suggesting that it disrupts the body's metabolism of alcohol.
"When your body absorbs quercetin from food or wine, most is converted to glucuronide by the liver in order to quickly eliminate it from the body," Waterhouse and Devi said.
The domino effect that follows this disruption? Extra acetaldehyde circulates, causing inflammation and headaches.
Other research has confirmed similar findings. In a 2023 study published in Scientific Reports, researchers reported red wine-induced headaches to be caused by the presence of quercetin and its glycosides, which upon metabolizing to quercetin glucuronide, inhibits ALDH2 enzyme activity.
Previous studies have also found that the level of quercetin is 4 to 8 times higher in sun-exposed grape clusters, compared to shaded clusters—such as Napa Valley cabernets and some Australian red wines.
Quercetin concentrations in red wine are higher than in white wine, so if you want to avoid the headaches—stick to the pinots and sauvignon blancs.
