(HuffPost) - Why do I feel like I already have a hangover the same night that I've been drinking? All I had was two glasses of red wine. With dinner.

It wasn't the first time I'd been stricken with a red wine headache; I tend to identify as a red drinker, but as a red drinker, headaches are a frustratingly common occurrence. What gives? Why do some people sometimes get headaches from drinking red wine?

"People come into the store citing red wine headaches all the time," Mike Johnson of Bottlerocket, a wine shop in New York City's Flatiron district, told me over the phone. "And typically, we believe that these headaches are a result of the drinker's sensitivity to sulfites." Brian Larky, a winemaker and the founder of Dalla Terra, said the same.

Sulfites are sulfuric compounds that occur naturally in wine, Mike told me--and they're also added to help preserve the wine. Some natural, biodynamic, or organic winemakers will add as little additional sulfites as possible (hence their "natural" labels), but "sulfites are necessary to stabilize the wine," Mike said. They stop the wine from refermenting once it's been bottled. (The legal sulfite addition is 350 parts per million, or ppm; most wines have about 120 ppm, and low-sulfite wines have between 0 and 20 ppm. And sulfites can naturally occur up to 40 ppm!)

Still, wine writer Alice Feiring says that if you get red wine headaches consistently, you should try a natural or biodynamic wine that has lower amounts of sulfites added, or at least uses only "molecular, elemental sulphur" rather than commercial, petrochemical sulphur. Alice maintains that there's a big difference between the two, and that she "immediately feels a pressure behind [her] eyes" when drinking conventional, rather than natural, low- or no-sulphur wines.