Alcohol tolerance differs among people. This especially gets clear when drinking with people of Asian descent. After a few drinks, they often show a red face and vomiting is imminent. The liver metabolises alcohol ethanol in two steps: in the first step, an enzyme Alcohol Dehydrogenase; ADH turns the toxic alcohol into another toxic substance, called acetaldehyde.
There are three different enzymes which the body uses to convert alcohol to acetaldehyde. All three of these enzymes work by stripping two hydrogen atoms off from the alcohol molecule. This converts the alcohol molecule into a molecule of acetaldehyde as shown in Figure 1. The acetaldehyde is then converted by a different enzyme into the acetyl radical as shown in Figure 2. Let us take a closer look at the enzymes which convert alcohol into acetaldehyde.
Research into the causes of alcoholism is a relatively recent scientific endeavor. One area of study which could lead to better understanding of the disease is the possibility of a genetic predisposition to alcoholism. Recent work has demonstrated that people have varying complements of enzymes to metabolize alcohol. Current knowledge is examined about the influence of various ethanol metabolizing enzymes on alcohol consumption by Asians and members of other ethnic groups. ADH is responsible for the metabolism of ethanol to acetaldehyde.
Alcohol intolerance is an inherited metabolic disorder. With alcohol intolerance, drinking just small or moderate amounts of alcohol ethanol causes unpleasant sensations. This metabolic disorder affects the enzyme that regulates alcohol metabolism. Alcohol flushing syndrome is a typical reaction.