Do you feel exhausted after a couple of drinks? Need constant Red Bull infusions to make it out of the bar? You might have a mutation that prevents you from becoming an addict.
The way the human body handles down alcohol is predominantly governed by the enzyme alcohol dehydrogenase (ADH), which breaks down the potentially toxic parts of booze. There's a variant of the ADH enzyme, however, which is associated with lower rates of alcohol dependence. But why do people who have this variant ADH1B*3 allele have a lower level of alcoholism?
Research carried out by scientists at the University of Missouri, Washington University and the University of California, San Diego may have found the rub. They gave a group of 91 willing young volunteers (all boasting the variant enzyme) a moderate dose of alcohol — 0.72 g/kg for males, 0.65 g/kg for females — and tracked what happens.
After hitting the sauce, the test subjects were measured for breath alcohol concentration, pulse rate, and feelings of sedation (sleepiness) and stimulation for 2.5 hours.
What happened was almost immediately after drinking, their pulse rate jumped, after which they all felt tired. People with the ADH1B*3 variant, which is common among people of African descent, all felt much higher levels of sedation than those who didn't have it.
In other words, the mutation knocks them out, so they don't have a tendency to get hooked on the sauce. It's a behavioral implication for how people drink, rather than an out-and-out genetic immunity. "This would be one explanation for their reduced drinking behavior – people are less likely to drink heavily when doing so makes them tired rather than stimulated or disinhibited," said researcherDenis M. McCarthy. "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."
Potentially, this discovery could be worked into a drug to help stop problem drinkers. Currently, the pharmaceutical Antabuse™ (disulfiram) acts to duplicate the aldehyde dehydrogenase variant ALDH2*2, so something similar could potentially be created for ADH1B*3.
So if you always feel exhausted after a drink or two, it may be your body trying to protect you.
Research presented in Alcoholism: Clinical and Experimental Research
Image from Flickr user jesus_leon