McCarthy's research is part of a new movement of the past few years that has begun to focus on biological and specific genetic factors that can alter expectancies.
Between one quarter and one half of individuals of Asian heritage possess a genetic variant of the alcohol metabolizing enzyme ALDH2, which has been linked to a deficiency in the low KmALDH2 isoenzyme, which can result in stronger physiological responses to alcohol.
"A significant percentage of these individuals experience a stronger response to alcohol than people without the gene do," said Gregory T. Smith, associate professor of psychology at the University of Kentucky. "In many cases, that stronger response is unpleasant. They may experience things like facial flushing, a higher pulse rate, and hormonal changes. In severe cases, individuals may experience nausea, vomiting, and tachycardia (an abnormally fast heartbeat)." The effects of ALDH2 gene status on response to alcohol have been likened to those of disulfiram (Antabuse), a drug therapy used to encourage abstinence in alcoholic persons. Not only are the physiological responses very similar, so too are the acting mechanisms - both inhibit the metabolism of acetaldehyde.
"This effect is so strong that people who have two copies of the ALDH2 allele (homozygous)," said McCarthy, "were not able to be included in our study. There is some risk involved in their ingesting even the relatively small amounts of alcohol included in this type of study. The effect is more modest for individuals with one ALDH2 allele (heterozygous), although the physiological response is still pronounced."
The study found that a genetic factor such as ALDH2 status appears to influence what people learn about the benefits of drinking. In particular, the ALDH2 gene appears to work as a protective factor for men by reducing high-risk expectancies. In other w
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14-Nov-2001