Alcohol Flush Increases Cancer Risk in Asia
March 25th, 2009
Asians would know what I’m talking about. You drink a few sips of alcohol and suddenly, you feel nauseated and hot, you face turns beet red, and your heart beats faster. Known as the “Asian Glow” or “Asian Flush”, this reaction to alcohol is a risk factor for cancer of the esophagus, one of the deadliest in the world.
The alcohol flushing response is an inherited genetic trait – deficiency in the enzyme aldehyde dehydrogenase 2 (ALDH2)- common among one third of Japanese, Chinese and Koreans.
Here’s how the enzyme works: In normal individuals, alcohol is broken down into a non-toxic forms by the action of two enzymes.
- Alcohol dehydrogenase (ADH) oxidizes alcohol into acetaldehyde. Acetaldehyde is a carcinogen that causes DNA damage, so the final steps in the metabolism of alcohol help get rid of this mutagen.
- Aldehyde dehydrogenase 2 (ALDH2) oxidizes acetaldehyde into acetic acid and CO2.
When ALDH2 is deficient, acetaldehyde accumulates in the body and creates an unpleasant flushing reaction. A person homozygote for the inactive ALDH2 gene has a completely defective enzyme and can not tolerate even small amounts of alcohol, essentially protecting them from the acetaldehyde carcinogen. However, a person heterozygote for the ALDH2 gene would only have decreased enzyme activity, which means they may grow to tolerate the unpleasant reaction to alcohol and become habitual heavy drinkers. It is this group of alcohol consumers that is associated with the greatest risk in esophageal cancer.
A collaboration between Japanese and American scientists found that 8% of the world population (540 million) have ALDH2-deficiency and exhibit the telling flushing response when consuming alcohol. Physicians can counsel ALDH2-deficient patients to lessen alcohol drinking and decrease the risk of esophageal cancer.
Read more about the study in the PLOS Medicine issued on March 24, 2009 - The Alcohol Flushing Response: An Unrecognized Risk Factor for Esophageal Cancer from Alcohol Consumption.
Image: PLoS Med 6(3): e1000050 doi:10.1371/journal.pmed.1000050 (CCAL)
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