Q: Why do many Asians flush when they drink alcohol? Is this dangerous?
A: Sometimes called the Asian flush or Asian glow because it is very common in people from East Asia (such as China, Japan, and Korea), this reaction occurs when a person has trouble metabolizing alcohol because of a genetic variant that impairs production of an enzyme that helps metabolize alcohol in the liver. As a result, acetaldehyde, a toxic byproduct of alcohol, isn’t broken down to harmless acetic acid, but instead builds up in the blood and liver. This dilates blood vessels, leading to flushing (redness and heat) in the face, neck, and sometimes shoulders and entire body. Headaches, dizziness, palpitations, and nausea may also occur.
This type of flushing is a sign of increased risk of serious health problems. For instance, it’s well known that excessive drinking can raise blood pressure and result in hypertension, but this is more likely to occur in people who flush—and at lower intakes. Thus a 2013 study found that middle-aged Korean “flushers” who consumed more than four drinks a week were twice as likely to develop hypertension as nonflushers who drank the same amount. Similarly, a 2012 study found that Chinese people with the genetic variant affecting acetaldehyde were at elevated risk for hypertension if they drank.
Some earlier studies also linked the flushing response to an increased risk of insulin resistance at a lower threshold of alcohol intake and to negative effects on blood cholesterol and triglycerides. Moreover, alcohol is a known risk factor for esophageal cancer, and a 2009 paper in PLOS Medicine suggested that people who have the flushing response are at even higher risk. This is perhaps because acetaldehyde is a carcinogen and can damage DNA.
What about non-Asians? Many other people also flush when they drink alcohol, but the flushing tends to be less intense and shorter-lasting than in Asians. There is much less research in this area, so it’s not clear what genetic and biochemical factors are involved in flushing in non-Asians or whether it is associated with the risks seen in Asians.
Words to the wise: If you are Asian and alcohol makes you flush, limit yourself to only an occasional drink or don’t drink at all. Even if you used to flush when you drank but no longer do so, you may still be at increased risk and should limit your alcohol intake.