This Could Be Why Red Wine Gives You Headaches

Drinking a glass of water before going to bed and skipping alcoholic beverages with high sugar content are just some of the common tactics deployed by those who hope to avoid a hangover. Yet despite the fact that not all red wine is sweet, for some people just one glass can still lead to pounding pain. New research from scientists at the University of California suggests a compound found in grapes could be the reason for wine-related headaches, BBC News reports.

Per the research team, red grapes contain an antioxidant (or flavanol) called quercetin, which makes it difficult for the body to metabolize alcohol properly. Quercetin can be found in other common fruits and vegetables such as apples and onions, but does not seem to cause headaches on its own. In fact, because quercetin has anti-inflammatory qualities, some even take it as a dietary supplement. It's when the quercetin compound mixes with alcohol that it can cause headaches for some.

Normally, our bodies process alcohol in two steps: First the alcohol is converted into a toxic compound called acetaldehyde, and then an enzyme called ALDH2 changes the acetaldehyde into acetate, which is essentially vinegar. But researchers found in the lab that quercetin can indirectly block the ALDH2, and the buildup of acetaldehyde is what could be the cause of headaches.

Red grapes that are exposed to more sunlight produce more quercetin. University of California researchers theorize more expensive red wines might be more likely to cause headaches because their grapes come from smaller crops with fewer leaves and more sunlight exposure.

On the other hand, Professor Roger Corder, an expert in experimental therapeutics at Queen Mary University of London, asserted to BBC News that the opposite is true. Other experts have a number of theories unrelated to quercetin that also attempt to explain why some people get headaches from red wine. For example, some research suggests that histamine, another compound found most commonly in red wine, is the cause of headaches. Histamine can dilate blood vessels, which could lead to a headache.

Despite the sound logic behind many of these theories, none have been fully proven. Researchers hope to conduct a study in the next few months to test the validity of the quercetin theory.

"We are finally on the right track toward explaining this millennia-old mystery," said Professor Morris Levin, research co-author and director of the Headache Center at the University of California, San Francisco, to the BBC. "The next step is to test it scientifically on people who develop these headaches, so stay tuned."