Decoding the Red Wine Headache: Quercetin's Role in Oenological Studies

In the sophisticated and multifaceted realm of oenology, a subject of increasing interest in recent years is the occurrence of headaches associated with red wine consumption. A significant stride in this area of study is being led by Professor Emeritus Andy Waterhouse of the University of California, Davis (UC Davis), drawing considerable attention from the media.

The research, focusing on quercetin, a natural compound found in various plants, including grape skins, delves into its potential role in causing headaches. Quercetin, also present in foods like capers, fresh dill, cilantro, fennel, red onions, radicchio, and watercress, has been identified as a likely culprit. Despite its availability as a dietary supplement, the U.S. Food and Drug Administration (FDA) has noted that it lacks proven medical benefits, cautioning against unfounded claims by some companies.

The ongoing study, in collaboration with the University of California, San Francisco (UCSF) School of Medicine, involves a methodology where individuals prone to these headaches will consume red wine and report the severity of their symptoms. This approach, though discomforting, is seen as a necessary step in medical science advancement.

Dating back to the 1990s, chemist and viticulturist Steven Price from Oregon State University conducted foundational research showing that sun exposure significantly increases quercetin levels in Pinot Noir grapes. These findings suggest a direct link between grape sun exposure and quercetin concentration in the resulting wines.

In this context, a Washington Post report suggested that opting for more affordable wines could be a strategy to avoid quercetin. While this may seem an oversimplification, Waterhouse indicates that this advice is not far off, as, on average, grapes for higher-priced wines are more sun-exposed.

In Europe, studies in Italy and Spain have augmented this field of research. The Italian study provided a list of 50 grape varieties classified by their quercetin levels, while the Spanish study focused on specific wines, revealing significant variations in quercetin levels in Cabernet Sauvignon, likely due to grape sun exposure.

Among grape varieties with lower quercetin levels are Sagrantino and Tannat, known for producing extremely tannic wines. In contrast, varieties like Cabernet Franc, Pinot Noir, and Nebbiolo have higher quercetin levels, which is noteworthy since Pinot Noir, with its seemingly "smooth and light" profile, might have been considered suitable for those prone to headaches.

Regarding viticulture and producing wines with lower quercetin levels, one proposed method is the use of shade cloths over the grapes, an investment some vineyards are already implementing due to heatwaves. However, both Waterhouse and Price caution that it is too early to deem these findings conclusive.

Reflecting on the evolution of knowledge about wine compounds and health, Price suggests that a full understanding of these dynamics is still some time away. As a provisional recommendation, he proposes opting for white wine to avoid red wine-related headaches, as quercetin is mainly found in grape skins, and there are differences in the solubility of this compound between red and white wines.

This area of research, though still in its early stages, opens an intriguing path in understanding how viticultural factors impact consumer health and well-being, marking a convergence of oenological science and medicine.