Does red wine give you headaches? Buy a cheaper bottle, scientists say.

Red wine is a welcome addition to most Thanksgiving dinners - that is, unless you’re one of the unlucky drinkers who gets a throbbing headache after just a glass or two.

Red wine headaches have almost certainly been around since humans discovered how to make booze out of fermented fruit. Scientists have long tried - to no avail - to understand why even a small glass of wine can make some feel like they need a pain reliever within 30 minutes of taking a sip.

In the past, tannins, sulfites and histamines have been blamed. Now, after testing about a dozen compounds found in red wine, findings from a team of researchers point to another culprit: quercetin, a compound found in grape skins.

“Quercetin absorbs ultraviolet light, so it’s sunscreen for the grapes,” said Andrew Waterhouse, a professor emeritus of oenology - also known as wine chemistry - at the University of California at Davis. Waterhouse, who co-authored the study that was published Monday in the journal Scientific Reports, said the amount of quercetin found in wine is directly related to the grapes’ sun exposure. “So, if you grow your grapes with a lot of shade, they don’t make much of this. But if you grow them where they get a lot of sun, then they make more quercetin.”

Quercetin doesn’t only help prevent grapes from scorching in the sun. In humans, it’s a powerful antioxidant that may help protect against heart disease and cancer. But when alcohol is added to the mix, quercetin can cause headaches, Waterhouse said.

“Your body has this system in place to get rid of the alcohol you drink, and the quercetin, it turns out, gums up the works,” he said. “Essentially, the quercetin from red wine stops the process halfway through.”

The human body has a complex process for eliminating alcohol and toxins that can be harmful to cells. Most alcohol - chemically speaking, ethanol - is broken down inside the liver, where two steps take place. First, enzymes help break down the ethanol molecule into acetaldehyde, a highly toxic substance and known carcinogen. Then, they turn the acetaldehyde into harmless molecules of acetate - a fatty acid that plays a role in the body’s energy production and lipid synthesis - which is eventually broken down into waste.

But when quercetin enters the bloodstream, it gets converted into quercetin glucuronide - a compound that blocks the enzyme that turns acetaldehyde into acetate. Left with the buildup of a “nasty toxin,” Waterhouse said, heads begin pounding.

It’s unclear how many people are affected by red wine headaches, but it’s a fairly common condition, said Morris Levin, a neurology professor at the University of California at San Francisco who co-authored the study. As the director of the university’s Headache Center, Levin said he has found “that maybe a third of my patients talk about a history of at least one red wine headache.” People who are prone to headaches and migraines appear to be particularly susceptible to red wine headaches - which “are very different than waking up with a hangover.”

Unlike the dreaded hangover, red wine headaches can happen “within a few minutes to a couple of hours after drinking the red wine,” Levin said - and they’re marked by a “throbbing sensation all around the head, nausea and just overall feeling crappy.”

But Waterhouse said there’s a “workaround, sort of” for red wine lovers who want to avoid headaches - that is, going for cheaper wine.

“As a general rule, cheaper wines have less quercetin,” Waterhouse said. “Usually it’s because the grapes get less sunlight than those in, say, the really expensive cabernet they make in the Napa Valley.”

But be warned: Less quercetin can mean the wine’s tannins might taste less silky.

Unfortunately, there’s still no cure for red wine headaches. Though Levin has in the past told his patients to hydrate or try taking ibuprofen before drinking, red wine headaches are “kind of resistant to treatment.”

So, will headaches always be the price to pay for a glass of red wine?

It remains to be seen.

Waterhouse and Levin are hoping to test their theory about quercetin with an upcoming clinical trial. Further research could focus not only on preventing or curing red wine headaches, but also lead to a better understanding of migraines as a whole.

In the meantime, the scientists said, people prone to the pesky headaches might have to be flexible about their vino of choice. Levin, who himself recently developed a somewhat unpleasant reaction to red wine, suggested opting for varietals like pinot noir and syrah, which tend to have a lower alcohol content.

“Plus, it’s always a good idea to work on stress reduction - particularly, around this time of year, to reduce the possibility of getting a headache,” Levin said.

Another option might be dumping red wine altogether. Unlike its crimson cousin, white wine doesn’t have quercetin since the grapes’ skins are removed before fermentation.

“For what it’s worth, white wine pairs terrifically with turkey,” Waterhouse said. “Rosé wine can be safe too.”