A person's perception of alcohol and how it tastes depends on genes, which may determine whether the person enjoys consuming alcohol or not, U.S. researchers have found.
Different versions of a so-called bitterness gene can influence whether people consider alcohol's taste to be more or less bitter, and thus more or less palatable, they say.
"In general, greater bitterness relates to lower liking, and because we generally tend to avoid eating or drinking things we don't like, lower liking for alcoholic beverages associates with lower intake," says researcher John Hayes at Penn State's College of Agricultural Sciences.
There are 25 genes in humans involved in taste receptors with which our tongues perceive bitterness, and the Penn State researchers undertook a study focusing on variations in two, identified as TAS2R13 and TAS2R38.
The TAS2R38 gene can show changes in its code associated with the perception of bitterness, they discovered, making people more or less sensitive to the sensation.
In the study, 96 adult participants were asked to rate the bitterness of a sample drink containing 16 percent alcohol.
Everyone possesses two copies of the TAS2R38 gene; study participants possessing two copies of the most sensitive gene version found the drink to be the most bitter, while those having two copies of the least sensitive variation reported it tasting less bitter.
Those with a mix of the gene versions fell in between.
"We would expect about 25 percent of the population to have two of the really sensitive forms, 25 percent insensitive, and 50 percent in the middle," Hayes says.
Human evolution has hard-wired us to prefer sweetness over bitterness, which influences beverage and food choices we make every day, the researchers point out.
People to whom the taste of alcohol seems less bitter as a result of their genetic makeup might be more likely to take up drinking, Hayes says, a factor that might be operating in those at risk of becoming problem drinkers.
"It seems unlikely the taste of alcohol matters at all once someone is alcohol-dependent," he said, although acknowledging that was speculation on his part. "Still, taste genetics may be an important risk factor before someone becomes dependent."
The study findings are the first to show that sensations and perception of sampled alcohol can vary as a function of genetics, the researchers said.
"The reason this work is significant is because it fills in this gap, because no one had shown in the lab that the alcohol actually tastes differently depending on which [version of the gene] you have," Hayes says.