Why does red wine cause headaches?

After drinking red wine, some people get a headache. Many components of this alcoholic beverage, such as sulphites, biogenic amines and tannin, have been accused of causing this unpleasantness. But recently, Andrew Waterhouse, professor of oenology, and Apramita Devi, researcher in food science and technology at the University of California at Davis (United States) suggest that the most likely culprit is something we don’t ‘may not have considered. To arrive at this discovery, the two chemists specializing in winemaking went through the list of phenolic compounds abundant in red wine.

Headaches: quercetin, “much more abundant in red wines”, to blame?

“We spotted an article showing that quercetin is a good inhibitor of the ALDH enzyme,” they wrote in a publication of The Conversation. As a reminder, alcohol metabolism takes place in two stages. First, ethanol is converted to acetaldehyde. Next, the ALDH enzyme converts acetaldehyde into acetate, a common and harmless substance. This second stage is slower for people who have red skin, hot flashes accompanied by a headache, because their ALDH is not very effective. The latter thus accumulate acetaldehyde, a somewhat toxic compound also linked to hangovers. “Quercetin is a phenolic compound found in the skins of grapes, so it is much more abundant in red wines than in white wines, because the skins of red grapes are left longer during the fermentation process than the skins of grapes whites”, added the experts.

To confirm this theory, the researchers carried out an experiment. During this test, they measured the speed at which the ALDH enzyme breaks down acetaldehyde. Then they added the suspected inhibitors, quercetin and other phenolic compounds, to see if they slowed the process. “We suggest that quercetin-3-glucoronide, derived from the different forms of quercetin in red wines, inhibits ALDH2, leading to elevated acetaldehyde levels and the subsequent onset of headache in predisposed subjects,” can we read in the results of a study published in the journal Scientific Reports. Simply put, quercetin glucuronide disrupts the metabolism of alcohol in the body. As a result, acetaldehyde circulates in excess, causing inflammation and headaches.

Human tests are needed to verify the hypothesis

Although the results are encouraging, scientists have reservations. “Other foods that contain quercetin are not associated with headaches, so you may not initially consider quercetin as the cause of the red wine problem.” So now they want to carry out work with humans by giving them two red wines with low and high levels of quercetin and asking them if one or the other wine causes a headache. “If high-quercetin wine causes more headaches, we’ll know we’re on the right track.”