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Washington, May 5 (ANI): Genetic differences in alcohol-metabolising enzymes, that make you sleepy when you drink, could significantly alter your risk for developing alcohol dependence (AD), according to a study.

One variant of the alcohol dehydrogenase enzyme, ADH1B*3, is observed almost exclusively in populations with African ancestry and has also been associated with reduced rates of AD.

The study has found that greater levels of sedation in African Americans with ADH1B*3 may explain their lower rates of AD.

“In one study looking at genetic samples from a number of African groups, the ADH1B*3 variant was found in almost every group. Furthermore, prior studies had shown that those with ADH1B*3 had reduced drinking and risk for AD, and this was thought to be due to the different form of ADH enzyme that people with this allele have. The goal of our study was to see if those with ADH1B*3 had different subjective and physiological response to alcohol compared to those who do not. This would be one explanation for why they drank less than others - they have a different experience from drinking,” explained Dr. Denis M. McCarthy, associate professor of psychology at the University of Missouri and corresponding author for the study.

Lara Ray from UCLA said that this focus on minority populations such as African Americans is sorely needed.

“In the pharmacogenomics era, failure to account for genetic differences in various ethnic groups may perpetuate or even expand health disparities. In this study, the authors do a very nice job of addressing unique risk and protective genetic factors for alcoholism in African Americans,” she added.

Researchers provided a moderate alcohol dose - 0.72 g/kg for males, 0.65 g/kg for females - to 91 African American adults (52 females, 39 males) aged 21 to 26 years.

All participants were genotyped for ADH1B*3 as well as additional polymorphisms that might contribute to alcohol response.

Results showed that ADH1B*3 was associated with higher levels of sedation, as well as a sharper increase in pulse rate immediately following alcohol consumption.

“The unique part of this study is showing that people with this allele have a different experience when they drink -they get more sedated, particularly when their BrAC is high,” said McCarthy.

“This would be one explanation for their reduced drinking behaviour - people are less likely to drink heavily when doing so makes them tired rather than stimulated or disinhibited. It is important for genetic research to go beyond demonstrating that a gene is related to a drinking disorder and instead demonstrating the steps by which the gene can exert its influence on that disorder,” he added.

The results of the study will be published in the latest issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View. (ANI)