New research suggests that scientists may be closer to understanding why red wine can cause headaches for some individuals. According to a study published in the journal Scientific Reports, a flavonol called quercetin, which naturally occurs in red wines, may interfere with the body's ability to metabolize alcohol. This interference can lead to the accumulation of toxins, resulting in swift headaches.
Quercetin is a plant compound that can be found in various fruits and vegetables, including grapes, berries, onions, and broccoli. When quercetin enters the bloodstream, it is converted into quercetin glucuronide, a different form that inhibits the metabolism of alcohol. As a result, this accumulation of alcohol in the body might explain why some individuals experience headaches after drinking red wine.
Red wine contains a significantly higher amount of phenolic compounds, especially flavonoids, in comparison to white wine. This makes red wine a primary contender responsible for these headaches. To investigate why headaches can occur after consuming just a couple of glasses of red wine, the researchers examined how quercetin might affect a particular genetic variant of an enzyme called ALDH2, which plays a crucial role in alcohol metabolism.
The deficiency of a properly functioning ALDH2 variant affects nearly 8% of the global population and is more prevalent among people of East Asian descent, with around 40% of this population being affected. People with a dysfunctional ALDH2 variant may experience symptoms such as skin flushing, heart palpitations, and headaches after drinking alcohol.
Normally, the enzyme alcohol dehydrogenase breaks down alcohol in the liver, converting it into acetaldehyde, a well-known toxin. The enzyme ALDH2 then further metabolizes acetaldehyde into less toxic acetate. The study researchers hypothesized that quercetin glucuronide might inhibit this enzyme variant, leading to an accumulation of acetaldehyde and subsequent headaches.
While the study provides interesting insights, experts caution that the research is more of a proposition of a theory rather than definitive proof. Dr. Jonas Spaak, an associate professor of cardiology at the Karolinska Institute, believes that the study, which was conducted in a lab and used substances at concentrations much higher than what would be found in the body after consuming wine, necessitates further investigation with human samples.
Dr. Vasilis Vasiliou, chair of the department of environmental health sciences at Yale University, adds that the inclusion of human samples is essential to verify the mechanism proposed in the study. Additionally, the derivative of quercetin used in the study is naturally generated in the liver and excreted by the kidneys, raising questions about its relevance outside controlled settings.
The authors of the study plan to conduct a small clinical trial to test their hypothesis by comparing red wines with high levels of quercetin to those with lower amounts. Nonetheless, it's important to remember that alcohol consumption, including red wine, should be enjoyed in moderation. While red wine is often associated with health benefits, there isn't solid evidence to support these claims. To minimize headaches, individuals can experiment with different wines from various producers and grape varieties, as the levels of headache-triggering compounds can vary significantly between different wines, advises Dr. Spaak.
Interestingly, the amount of quercetin in grapes is influenced by the exposure to sunlight. Grapes grown in regions like Napa Valley, where the clusters are more exposed, tend to have higher levels of quercetin. This may explain why some individuals may have better luck with cheaper red wines or even white wines, as they generally have lower levels of flavonols overall.