Red wine headache theory

If you have ever had a bad headache after drinking red wine, it may not be just the alcohol. A new theory blames wines made from grapes that have been exposed to lots of sunlight.

Acetaldehyde is created when alcohol breaks down in the body and researchers know that high levels of acetaldehyde can cause facial flushing, headache and nausea. The body's defence is to produce an enzyme known as ALDH2 which breaks down the acetaldehyde, helping to limit the effects of over indulging in wine.

However, wines that are high in quercetin inhibit the ALDH2 enzyme from breaking down the harmful acetaldehyde, making the risk of headaches worse. Red wine was found to have much higher levels of quercetin than white wine, beer or even spirits.

Sun-exposed grape clusters exhibit quercetin levels that are 4 to 8 times higher than those in shaded clusters. Some grape varieties can also be higher in quercetin . Vitis vinifera red wines exhibited chemical levels ranging from 10.26 to 13.81 mg/L, and Italian Sangiovese wine showed levels as high as 19 mg/L. This variability further emphasizes the role of quercetin in contributing to red wine headaches and indicates that some red wines may be more problematic than others.