Putting enzymes to the test
Testing ALDH was the next step. We set up an inhibition test in test tubes. In the test we measured how quickly the enzyme ALDH breaks down acetaldehyde. We then added the suspected inhibitors – quercetin, as well as some other phenols we wanted to test – to see if they slowed the process.
The chemical structure of quercetin, which can cause red wine headaches.
The chemical structure of quercetin, which can cause red wine headaches.
Credit: Johannes Botne (CC BY-SA)
These tests confirmed that quercetin was a good inhibitor. Some other phenols had varying effects, but quercetin glucuronide was the winner. When your body absorbs quercetin from food or wine, most of it is converted by the liver into glucuronide so it can be quickly removed from the body.
Our enzyme tests show that quercetin glucuronide disrupts alcohol metabolism in your body. This disruption means extra acetaldehyde is circulating, causing inflammation and headaches. This discovery points to what is known as a secondary or synergistic effect.
These secondary effects are much more difficult to identify because two factors must both be at play for the outcome to occur. In this case, other foods containing quercetin are not associated with headaches, so you might not initially consider quercetin as the cause of the red wine problem.
The next step could be to give subjects two red wines containing little and much quercetin and ask whether either wine causes a headache. If the high quercetin wine causes more headaches, we know we are on the right track.
So if quercetin causes headaches, are there red wines without it? Unfortunately, the data available on specific wines is far too limited to provide any useful advice. However, grapes exposed to the sun do produce more quercetin, and many cheap red wines are made from grapes that see less sunlight.
If you're willing to take a chance, look for an inexpensive, lighter red wine.
Andrew Waterhouse is a professor of enology at the University of California, Davis, and Apramita Devi is a postdoctoral fellow in food science and technology, University of California, Davis.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
