It’s a classic scene: a dinner with friends, a glass or two of red wine, and the next day, a headache that won’t let you go. Often attributed to sulphites or tannins, this phenomenon could have another explanation. In an article in The Conversation* and a study published by chemists at the University of California, quercetin, a flavonoid naturally found in the skin of grapes, emerges as a potential new culprit.
What is quercetin?
Quercetin is a substance naturally present in the skin of grapes, and therefore in wine. It belongs to a family of compounds called flavonoids, known for their antioxidant properties. It is also found in other foods such as apples, onions or tea, but it is in red wine that it is particularly concentrated, due to the prolonged maceration of the grape skins during the longer fermentation. than that of white wines in particular.
A chemical phenomenon
To understand the effect of this molecule on our body, here are some necessary clarifications. When you drink alcohol, your body breaks it down in several steps: First, ethanol is converted into acetaldehyde using an enzyme called alcohol dehydrogenase (ADH). Then acetaldehyde becomes acetic acid thanks to another enzyme, aldehyde dehydrogenase (ALDH). The problem ? Acetaldehyde is a toxic substance which, in excessive quantities, causes headaches, nausea and other unpleasant symptoms. This is where quercetin comes in: according to researchers, it prevents acetaldehyde from being properly eliminated. Result: acetaldehyde stays longer in your body, which amplifies unwanted effects, such as those famous headaches.
Although current research points the finger at quercetin, other compounds in red wine are also thought to play a role, and reactions vary between individuals. While waiting to know more, the scientists in charge of the study specify that “grapes exposed to the sun produce more quercetin”. They therefore advise consuming lighter and preferably inexpensive red wines because “many inexpensive red wines are made from grapes less exposed to the sun”.
* Why does red wine cause headaches? Our research has highlighted a compound present in the skin of grapes