Human aldehyde dehydrogenases: their role in alcoholism

This article surveys the state of our knowledge concerning the biochemical and genetic variations in aldehyde dehydrogenases (ALDHs) in humans and their role in alcohol sensitivity, alcohol drinking habits, and alcoholism. Variations in acetaldehyde metabolism via genetically determined polymorphisms in ALDH enzymes seem to play an important role in individual and racial differences in acute and chronic effects of alcohol drinking as well as towards vulnerability to organ damage after chronic alcohol abuse. Alcohol sensitivity and associated discomfort symptoms accompanying alcohol ingestion may be determinantal for the significantly low incidence of alcoholism among Japanese, Chinese and other Orientals of Mongoloid origin. An abnormal ALDH isozyme has been found to be widely prevalent among individuals of Mongoloid race, and is mainly responsible for the acute sensitivity to alcohol commonly observed in this race. Persons sensitive to alcohol by virtue of their genetically controlled ALDH isozyme deficiency may be discouraged from drinking large amounts of alcohol in their daily life due to the initial adverse reaction experienced after drinking alcohol, and thus are protected against alcoholism.