The role of aldehyde dehydrogenase isozyme variance in alcohol sensitivity, drinking habits formation and the development of alcoholism in Japan, Taiwan and the Philippines

It is known that aldehyde dehydrogenase (ALDH) responsible for metabolism of acetaldehyde deriving from ethanol has two distinct forms of isozymes: ALDH-I (low Km ALDH) and ALDH-II (high Km ALDH), and that many Orientals lack ALDH-I isozyme genetically. In the present study, the role of ALDH isozyme variance in the alcohol sensitivity, drinking habits formation and the development of alcoholism was investigated in Japan, Taiwan and the Phillipines. Isozyme analysis using isoelectric focusing of hair roots specimens from normal volunteers or schizophrenics revealed that about 42% of Japanese, 35% of Taiwanese and 12% of Phillipines were ALDH-I deficient. Questionnaire study of Japanese volunteers indicated that ALDH-I deficient individuals showed flushing, palpitation and other uncomfortable somatic signs, due to reduced metabolism of acetaldehyde, much more frequently than ALDH-I positive ones. Consequently, it occurred that only 19% (8/42) of ALDH-I deficient persons, in contrast to 49% (29/59) of ALDH-I positive ones, were drinking habitually. Patients with alcoholism showed much smaller percentages of ALDH-I deficiency: 4% (5/113) in Japan and 10% (3/29) in Taiwan, than those of control subjects. Summarizing these data, a hypothesis can be presented that genetically derived difference of ALDH activities is one of the determining factors in the sensitivity to alcohol, formation of drinking habits, and finally in the development of alcoholism, at least among Oriental peoples.