Sometimes life just ain't fair. While your friends are guzzling the bubbly on New Year's Eve, if you are Asian, especially Chinese, Japanese, or Korean, you might want to stick with ginger ale. Otherwise, there is a pretty good chance that your new year is going to get off to a very bad start.
This is because of a poison called acetaldehyde, and a mutation in a gene that would normally get rid of it, which just happens to be fairly common among people descended from east Asians. Estimates suggest that possibly as many as half of all people with ancestry from these areas are affected, and the only way to avoid the toxic effects of acetaldehyde is to avoid alcohol altogether. There is no magic pill to make this process function properly.
This is all because of biochemistry: the metabolism of ethanol occurs in two distinct steps, each controlled by a different liver enzyme. When the second step doesn't work properly, people run into trouble.
Step 1: Alcohol is oxidized in the liver by an enzyme called alcohol dehydrogenase to form acetaldehyde a rather hideous chemical.
Step 2: The acetaldehyde is removed from the blood by a second step, which is carried out by a different enzyme called acetaldehyde dehydrogenase. It is converted into acetic acid (vinegar), which is normally harmless, and later to CO2 and water.
The enzyme in Step 2 is made by a gene called ALDH2. But, many Asians have a variant of this gene which makes the protein non-functional. This results in buildup of acetaldehyde in the blood something to be avoided, because it leads to nausea, vomiting, headache, increased heart rate and allergic symptoms, one of which is referred to as the "Asian Flush," where the drinker's face turns red. This is why many people of Asian descent do not drink. Hangovers are at least partly due to acetaldehyde, which is also a suspected carcinogen, in case you needed another reason to avoid it.
It is possible to simulate these effects by blocking the second step chemically. There is a drug that is used specifically for this purpose, disulfiram (Antabuse). Antabuse is a treatment for alcoholics, but a very unpleasant one. If a person who has taken Antabuse drinks even a sip of alcohol, they will become violently ill from the acetaldehyde that is formed, but cannot be processed. Although the drug works very well, it is not a great treatment for alcoholism, since it is far easier to just stop taking the pills than drinking.
Finally, when you wake up on January 1st and wish you were dead, the following graphic is unlikely to make you feel a whole lot better, unless you really like pretty colors. It is a representation of the structure of acetaldehyde dehydrogenase (blue). The area with the yellow circle is where acetaldehyde is normally converted to acetic acid. It is the same place where disulfiram binds and screws up the entire process. Bottoms up!
Josh Bloom
Director of Chemical and Pharmaceutical Science
Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.
