Alcohol flush reaction, also known as “Asian flush”, is a condition when a person develops flushing, redness, nausea and even tachycardia after alcohol consumption. It occurs in predominantly Asians and about 36% of East Asians including Japanese, Chinese and Koreans experience this condition. When alcohol is consumed, alcohol dehydrogenases metabolizes ethanol into acetaldehyde which is a toxic and carcinogenic agent. Then, aldehyde dehydrogenase 2(ALDH2) metabolizes acetaldehyde to acetate. In some East Asian populations, a lysine allele replaces the glutamate allele in position 487 in the enzyme ALDH2. Lys/Lys homozygotes has no ALDH2 activity whereas Lys/Glu heterozygotes has reduced ALDH2 activity (Brooks). Therefore, “Asian flush” is mostly due to an inherited deficiency in the enzyme ALDH2 since acetaldehyde isn’t metabolized and accumulates in the body (Brooks). It can be used as a biomarker or predictor for ALDH2 deficiency. People with ALDH2 deficiency experience higher amounts of DNA and chromosomal damage than people with fully active ALDH2. High amounts of acetaldehyde can be associated with higher cancer risk. Studies have shown that facial flushing due to the acetaldehyde was associated with higher cancer risk, such as squamous cell esophageal cancer especially in East Asian men (Zhang). Esophageal cancer is one of the deadliest cancers in the world so it is essential for doctors to be informed about this so they can question and screen patients about previous episodes of alcohol-induced flushing. It is important for ALDH2-deficient patients to be educated on limiting their alcohol consumption which can possibly decrease the risk of developing esophageal cancer.
Brooks PJ, Enoch MA, Goldman D, Li TK, Yokoyama A. The alcohol flushing response: an unrecognized risk factor for esophageal cancer from alcohol consumption. PLoS Med. 2009;6(3):e50. doi:10.1371/journal.pmed.1000050
Zhang J, Zhang S, Song Y, et al. Facial flushing after alcohol consumption and the risk of cancer: A meta-analysis. Medicine (Baltimore). 2017;96(13):e6506. doi:10.1097/MD.0000000000006506