An Unexpected Chemical May Be the Cause of Red Wine Headaches

Red wine headaches have been a well-documented phenomenon since Roman times, likely dating back to the origins of winemaking itself, around 10,000 years ago. As chemists focused on winemaking, we set out to uncover the true culprit behind this age-old discomfort.

Debunking Common Culprits

Over the years, sulfites, biogenic amines, and tannins have been frequently blamed for red wine headaches. However, our research indicates that the true source might be a chemical that hasn’t received as much attention.

Sulfites, for example, have often been blamed for various health issues, especially after the 1990s when US regulations required their labeling on wine bottles. Yet, evidence linking sulfites to headaches is scarce. Other foods containing similar sulfite levels don’t cause the same reactions, and white wines, which contain comparable sulfite amounts as red, rarely cause headaches.

The body also naturally produces about 700 milligrams of sulfites daily during protein metabolism, making the 20 milligrams in a glass of wine unlikely to overwhelm your system.

Biogenic amines, nitrogenous compounds found in fermented foods, are another suspect. While these can indeed trigger headaches, the levels present in wine are too low to be a significant factor.

Tannins, a class of phenolic compounds abundant in red wines but scarce in white wines, also seem like a plausible cause. These compounds are common in plants and contribute to disease resistance and seed dispersion. However, tannins are present in many other foods, such as tea and chocolate, which generally don’t lead to headaches. Furthermore, phenolics like tannins are antioxidants and unlikely to cause the inflammation associated with headaches.

A Potential Clue: The Role of Quercetin

Some individuals experience flushed skin and headaches when consuming alcohol due to inefficiencies in their body’s ability to metabolize it. This process involves two steps: ethanol is first converted into acetaldehyde, a toxic compound, and then acetaldehyde is broken down into acetate by the enzyme ALDH. When ALDH is inefficient, acetaldehyde builds up, leading to inflammation and headaches.

We hypothesized that something in red wine might inhibit ALDH, slowing this metabolic process and causing acetaldehyde accumulation. Among the phenolics in red wine, quercetin stood out as a potential candidate. Found in grape skins, quercetin is far more concentrated in red wines due to the extended contact with the skins during fermentation.

Testing the Hypothesis

To investigate, we conducted enzyme inhibition tests in a lab. By observing the activity of ALDH in breaking down acetaldehyde, we tested whether quercetin and other phenolics could slow the process. The results confirmed that quercetin is a strong ALDH inhibitor, and its glucuronide form—produced when the body metabolizes quercetin—was particularly effective at disrupting alcohol metabolism.

This disruption allows more acetaldehyde to circulate, triggering inflammation and headaches. Interestingly, this is a secondary effect, requiring the combination of quercetin and alcohol to produce symptoms. Foods containing quercetin alone don’t typically cause headaches, making it easy to overlook this connection.

To confirm quercetin’s role, future studies could involve human trials comparing headaches triggered by wines with varying quercetin levels. For now, identifying wines low in quercetin remains challenging, as detailed data is unavailable. However, grapes exposed to more sunlight produce higher quercetin levels, so lighter, inexpensive reds—often made from less sun-exposed grapes—might be a safer bet for those prone to headaches.

While further research is needed, this discovery highlights how one overlooked compound could hold the key to resolving the mystery of red wine headaches.

Read the original article on: Science Alert

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