The first is a variant in the gene that encodes for an enzyme, alcohol dehydrogenase, which breaks down alcohol into acetaldehyde. A whopping 80 percent of Asians have a gene variant that vastly increases the efficiency of alcohol conversion to acetaldehyde, by up to 100 times. So far so good.
The second gene variant is for another enzyme called acetaldehyde dehydrogenase (ALDH2) that metabolizes acetaldehyde, making it less efficient than normal. Acetaldehyde causes blood vessels to dilate resulting in the characteristic flush, and also raises the heart rate.
Asians break down alcohol faster, but it takes them longer to metabolize acetaldehyde, and acetaldehyde is more toxic than alcohol! It is also a well-known carcinogen! And hence this makes Asians less tolerant to alcohol than any other ethnicity.If you suffer from this syndrome you might want to consider other options when going out for a drink with your friends.
