The following essay is reproduced with permission. The Conversation is an online publication covering the latest research.
Medical reports of red wine headaches date back to Roman times, but the experience is probably as old as winemaking, about 10,000 years ago. As chemists specializing in winemaking, we wanted to understand the cause of these headaches.
Many components of red wine have been blamed for this scourge, with sulfites, biogenic amines, and tannins being the most famous. Our research shows that the most likely culprit is someone you might not have thought of.
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common suspect
Sulfites have been popular as a surrogate for all sorts of ailments since the 1990s, when wine was required to be labeled with sulfites. However, there is less evidence that sulfites are directly linked to headaches, and other foods do not contain the same effects at comparable levels as wine. White wine contains the same amount of sulfites as red wine.
The body also produces about 700 milligrams of sulfites each day when it metabolizes protein in food and excretes it as sulfates. To do this, it contains a compound called sulfite oxidase, which produces sulfate from sulfite. Even 20 milligrams in a glass of wine is unlikely to overwhelm sulfite oxidase.
Some people point to biogenic amines as the cause of red wine headaches. These are nitrogen-containing substances found in many fermented or spoiled foods that can cause headaches, but the amounts in wine are so small that they are not a problem.
As for tannins, it can be inferred that white wines contain only trace amounts, while red wines contain significant amounts. Tannins are phenolic compounds found in all plants and typically play roles in preventing disease, resisting predation, and facilitating seed dispersal by animals.
However, grape skins and seeds contain many phenolic compounds in addition to the tannins found in red wine during the wine-making process, but white wine does not. There is a possibility that
Tannins are also found in many other common products that generally do not cause headaches, such as tea and chocolate. Phenols are also good antioxidants and are less likely to cause the inflammation that causes headaches.
red wine flash
Some people experience redness in their skin, facial redness, and headaches when they drink alcohol. This headache is caused by a delay in the metabolic steps when your body breaks down alcohol.
Metabolism of alcohol occurs in two stages. First, ethanol is converted to acetaldehyde. The enzyme ALDH then converts acetaldehyde to acetate, a common and harmless substance. In people with flushed skin, this second step is slower because ALDH is less efficient. They build up acetaldehyde, a somewhat toxic compound that is also associated with hangovers.
So, if a unique substance found in red wine can inhibit ALDH and slow down the second metabolic step, could it increase acetaldehyde levels and cause headaches?To answer this question, we We looked at the list of phenols that are abundant in.
We spied a paper showing that quercetin is a good inhibitor of ALDH. Quercetin is a phenolic compound found in grape skins, and because red grape skins are left for longer during the fermentation process than white grape skins, quercetin is more present in red wines than white wines.
try enzymes
The next step was testing ALDH. We set up an inhibition assay in vitro. This assay measured the rate at which the enzyme ALDH degrades acetaldehyde. They then added the suspected inhibitor, quercetin, and other phenols they wanted to test to see if they slowed the process.
These tests confirmed that quercetin is a good inhibitor. Other phenols had various effects, but quercetin glucuronide was superior. When the body absorbs quercetin from food or wine, it is mostly converted into glucuronides by the liver for immediate elimination from the body.
Our enzyme tests suggest that quercetin glucuronide interferes with the body’s alcohol metabolism. This disruption means excess acetaldehyde circulates, causing inflammation and headaches. This finding indicates a so-called second-order, or synergistic, effect.
These secondary effects are very difficult to identify because two factors must both be in play for the outcome to occur. In this case, you may not initially think that quercetin is the cause of your red wine problem because other foods containing quercetin are not associated with headaches.
The next step was to give subjects two types of red wine, one with low quercetin content and one with high content, and ask them which wine caused their headaches. If wines high in quercetin cause more headaches, we know we’re on the right track.
So, if quercetin causes headaches, are there red wines that don’t contain quercetin? Unfortunately, the data available on specific wines is too limited to provide useful advice. It is not possible. However, grapes exposed to the sun produce more quercetin, and many cheap red wines are made from grapes that don’t get sunlight.
If you want to take a risk, look for an inexpensive, light red wine.
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