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.
References
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
Alcohol flush syndrome, also known as Asian flush or Asian glow, is facial flushing seen after drinking alcohol. The flush reaction can extend to the neck, shoulders, and in rare cases, the entire body. Alcohol gets broken down in two steps. Upon consumption of alcohol, alcohol dehydrogenase (ADH) (an enzyme) converts alcohol into acetaldehyde, a toxic byproduct. Aldehyde dehydrogenase (ALDH2) (an enzyme) metabolizes acetaldehyde into acetate, a less toxic byproduct. In those with ALDH2 enzyme deficiency, acetaldehyde builds up due to the inability to break down into acetate. The body recognizes this as an allergic reaction and releases histamine. The histamine release induces increased heart rate, nausea, and flushing. The blood vessels dilate, causing superficial erythema that comes in blotches. To some, it may be a mere side effect of drinking, to others, they are self-conscious and it affects their social life.
There has been a lot of research done to prevent alcohol flush. Many over-the-counter products have been marketed, however, there are negative side effects if mixed with alcohol, contradicting the purpose of the product itself. Some at-home remedies consist of eating a heavy meal before drinking, to slow down the metabolism of alcohol, and slowing down acetaldehyde buildup. Another remedy is to simply drink slowly. Spacing out drinks can aid in allowing the body to flush out acetaldehyde, however, this may not be convenient depending on certain circumstances.
Flushing has been linked to hypertension and certain types of cancer such as esophageal cancer. The cancer, however, was not linked to women as it was to men. Aldehyde dehydrogenase 2 enzymatic deficiency is most common in East Asians, affecting nearly 560 million individuals. In a study conducted in 2013, the blood pressure of Korean men was observed among those who did and did not experience facial flush upon alcohol consumption. Upon completion of the study, it was determined that the men who drank and experienced flushing had a significantly higher risk of blood pressure when drinking four or more drinks per week.
According to the American Cancer Society, acetaldehyde from alcohol consumption is a group 1 carcinogen. There is evidence to prove it can cause cancer in humans. Dr. Chen, the country director at Stanford Center for Asian Health Research and Education, conducted an ethanol patch test. Subjects were brought in, where a small amount of ethanol was applied to a bandaid and attached to their skin for 20 minutes. Blood vessels immediately dilated, causing a flushing reaction in the area. Another over-the-counter remedy commonly taken is an antihistamine. This may prevent skin flushing, however, acetaldehyde levels remain in the blood. The goal when drinking is usually to remove the flushing reaction. On the other hand, many have learned to embrace the temporary flush or have simply reduced alcohol intake which would benefit the individual.
References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2659709/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10535860/
https://www.niaaa.nih.gov/publications/alcohol-flush-reaction-does-drinking-alcohol-make-your-face-red#:~:text=Some%20people%20who%20drink%20alcohol,or%20an%20episode%20of%20migraine.