Why do some people report headaches soon after drinking a glass or two of red wine?

In most people, an enzyme metabolizes alcohol into acetaldehyde, then a second enzyme—aldehyde dehydrogenase (ALDH)—converts acetaldehyde into acetate.

But some people (especially East Asians) have a less-active variant of ALDH, so the acetaldehyde builds up, causing headaches, flushing, and nausea.

Red wine is higher in phenols—components of grape skin and seeds—than white wine. And when researchers tested 13 phenols on ALDH activity in test tubes, several—especially quercetin-3-glucuronide—inhibited the enzyme.

What to do

Human studies are needed, but if red wine gives you a headache, try white.