AncestryDNA® Traits Learning Hub

AncestryDNA® Traits Learning Hub

AncestryDNA® Traits
Learning Hub

Alcohol Flush

If your face turns red after drinking a glass of wine, a beer, or other type of alcoholic beverage, you may have an alcohol flush reaction. This reaction is usually caused by a specific gene associated with how your body digests alcohol.

However, rosacea—a skin condition not related to alcohol intolerance or alcohol allergy—can also cause some people to have a red face when drinking alcohol. An AncestryDNA® + Traits test can tell you if your DNA indicates you're likely to have a genetic alcohol intolerance.

Alcohol Intolerance vs. Alcohol Allergy

An alcohol intolerance means your body has trouble digesting alcohol because there's a problem with the enzyme— alcohol dehydrogenase (ADH)—that helps break down alcohol.

The alcohol flush reaction is a key sign of alcohol intolerance. In addition to facial flushing, you might also have symptoms or side effects from consuming alcohol like nausea, vomiting, stuffy nose, headache, diarrhoea, heart palpitations, and asthma flare-ups (if you already have asthma).

Alcohol intolerance isn't the same as an alcohol allergy, though the two terms often get used synonymously. With an alcohol allergy, your own immune system causes you to have an allergic reaction. An alcohol allergy is less common than alcohol intolerance.

Alcohol Allergy Symptoms

When someone has an allergic reaction to alcohol, they are usually allergic to an ingredient in the alcohol. In beer, its grain product ingredients—like yeast, hops, wheat, or barley—can cause the allergic reaction. With wine, the allergy is often caused by the grapes or chemicals and preservatives used to make the alcohol. Red wine is the most common alcohol to cause allergic reactions.

Some symptoms or effects of alcohol allergy and alcohol intolerance are the same, such as nausea. An allergy to any amount of alcohol may also cause:

  • Skin rash or hives
  • Itching
  • Swelling, especially around lips/mouth
  • Trouble breathing
  • Severe stomach cramps

The most life-threatening allergic reaction is anaphylaxis, which sends your body into shock and closes up your airways. This is a medical emergency and requires epinephrine: Call 999 or 112.

The Genetics of an Alcohol Flush Reaction

Ancestry scientists found over 6,500 DNA markers associated with the alcohol flush reaction. Several of these markers are near the gene ALDH2, which helps in metabolising—or digesting—alcohol. The gene ALDH2 makes an enzyme that turns a by-product of alcohol, called acetaldehyde, into something non-toxic. Some people have a variation of the ALDH2 gene that makes a less active or inactive version of the enzyme. This makes it harder for their body to metabolise alcohol and causes too much acetaldehyde to stay in their bloodstream.

When too much acetaldehyde builds up in your body, it makes your blood vessels open. This causes the flushed face and other symptoms. Whereas some conditions are a mix of genetics and other factors, the alcohol flush reaction that happens because of alcohol intolerance is entirely genetic. Some therapies—like topical cream, histamine blockers, or lasers—aim to reduce redness. But they do not affect or change your ALDH2 deficiency.

Interesting Facts About Alcohol Flush

About 8 percent of people worldwide have the alcohol flush reaction. The reaction is more common in people of Korean, Chinese, and Japanese descent. Somewhere between 36 percent and 70 percent of East Asian people experience facial flushing with alcohol.

If you have the genetic variant, the most effective way to avoid the flush reaction is to limit your alcohol use. Some research indicates that people with an ALDH2 deficiency who drink alcohol may also be at a higher risk for certain diseases, like cancer and liver problems.

For people whose flushing is related to rosacea, you may find that certain types of alcohol turn your face red more than others. You can learn what triggers the rosacea facial flushing by paying attention to what you're drinking when it happens.



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"Alcohol Intolerance." Cleveland Clinic. Accessed August 4, 2023.

Breeze, Jarrod. "Alcohol Allergy." WebMD. Accessed March 28, 2022.

Brooks, Philip J., Mary-Ann Enoch, et al. "The Alcohol Flushing Response: An Unrecognised Risk Factor for Esophageal Cancer from Alcohol Consumption." PLoS Med. March 2009.

"Facial Flushing: Should You Worry If Your Face Turns Red When You Drink?" Cleveland Clinic. Accessed August 4, 2023.

Grey, Heather. "Alcohol Allergies." Accessed August 4, 2023. Healthline.

Marks, Julie. "Does Your Face Turn Red When You Drink? Here’s Why." Accessed August 4, 2023. Healthline.

Yu, Wesley, et al. "Treatment of Asian Flushing Syndrome With Topical Alpha Agonists." U.S. National Library of Medicine. Accessed August 4, 2023.

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