Why Does Red Wine Give Me A Headache? Many Scientists Blame It On The Grape Skins

There are a few ideas as to what causes the notorious “red wine headache”. A leading theory is that some people lack the enzymes to break down the high concentrations of chemicals commonly found in the grape, especially their skin. 

Red wine is fermented with the grape skins on, unlike white wine, which is made after the skins are removed. This leaves red wine with higher levels of compounds found in the skins, such as histamine and tannins.

Elevated histamine levels in the blood can dilate blood vessels and may cause a headache, while tannins can activate neurotransmitters associated with pain, so there is some validity to these claims, although they are far from concretely proven.

Many headache sufferers also blame sulfites, preservative salts added to stop fermentation. Yet sulfites are present in many foods and drinks, and some sources even suggest that white and sweet wines contain higher levels than red wine. 

The precise cause of red wine headaches eluded scientists for some time, until a study published in the journal Scientific Reports in 2023 put forward another strong candidate: a flavor-giving plant pigment called quercetin.

Quercetin is found in many fruits and vegetables, but it becomes problematic when mixed with booze because it impedes the body’s ability to break down alcohol.

Normally, the enzyme ALDH2 breaks down an alcohol by-product called acetaldehyde, which can cause red flushes and headaches if it builds up. However, quercetin can block the action of ALDH2, leading to higher acetaldehyde levels and, therefore, a sore head. 

Once again, quercetin is primarily found in the skins of grapes, so it’s much more abundant in red than white wines. Interestingly, quercetin is created by the grapes being drenched in sunlight as they grow, a process that is typically associated with higher quality wine. This would imply that finer, more expensive wines are more likely to stir up a headache than cheaper wines. 

However, the study wasn’t able to identify why some people are more susceptible to post-vino gloom than others. 

It might be that roughly 8 percent of the global population, mostly people of East Asian descent, have a deficiency in the enzyme ALDH2, which can cause headaches and red flushes after a night on the bottle. Even for those with a minor deficiency of ALDH2, the added impact of quercetin in red wine could push acetaldehyde levels past the threshold that triggers a headache.

The same team of researchers is hoping to pry deeper into this question with a follow-up trial that will involve giving headache-prone drinkers different doses of a quercetin supplement or a placebo pill, along with a standard drink of straight vodka.

“We are finally on the right track toward explaining this millennia-old mystery. The next step is to test it scientifically on people who develop these headaches, so stay tuned,” Professor Morris Levin, co-author and an expert in neurology and director of the Headache Center at the University of California, San Francisco, told the BBC in 2023.