Genetically determined taste perceptions could lead some people to become teetotalers and others to become alcoholics, a new study suggests.
John E. Hayes and colleagues at Pennsylvania State University studied the genetic make-up of 93 adults, looking in particular for so-called bitter-receptor genes, which are responsible for people's sensitivity to bitter tastes.
The researchers then asked participants to taste and rate alcohol samples in a laboratory.
The findings suggest that two genetic variations influence perceptions about the taste of alcohol and may shape how people respond to their first sips of beer, wine or booze, according to the study published in Alcoholism: Clinical and Experimental Research.
"Some people might be more vulnerable because of how they experience bitterness, and that's because of differences in their genetics," Hayes told Reuters Health in a telephone interview. "If it's more bitter, you like it less, is the assumption."
Hayes is a food science professor at Pennsylvania State in University Park.
"The bitterness they perceived was influenced by which gene they had, and it was exactly the same direction as we would have expected from the previous work on alcohol intake," he said.
Prior research, he said, shows that the more people taste bitterness, the less likely they are to drink alcohol, and vice-versa.
"The study suggests that people may or may not be predisposed toward liking alcoholic beverages when they first try them. Just like people can be colour blind, it turns out some of us are more or less taste blind," Hayes said.
Humans have about 25 different bitter-taste receptor genes, he said. He studied two: TAS2R13 and RAS2R38. Both of these have been linked in previous studies to a tendency to drink when the gene is "turned off" and not to drink when it is turned on, Hayes said.
The findings show that participants with one of the variants of the bitterness gene rated the taste of alcohol as 25 per cent more intense, he said.
People with the bitterness variant of the RAS2R38 gene drank half as often as those without it, Hayes said.
"Biology is not destiny, but it could play a role. Environment's hugely important too," Hayes said.
"Some people might find it easier to drink, but they still might not drink more because of religion, culture. There's lots of factors that can influence what we choose to eat," he said.
Hayes said he and his team have asked the National Institutes of Health for a grant to follow 1,000 college students for their first year at school, to see how genetic differences in taste perception might influence their drinking habits.
If they find in the students what they found in the laboratory, it could confirm that these genes might be good targets for biologically tailored interventions to prevent and treat alcoholism, Hayes said.
Researchers first identified a genetic basis for variability in the perception of bitterness in 1932, Hayes noted in a previous report. Natural selection to avoid eating bitter plant toxins may have driven the genetic variation.
Nowadays, alcoholic beverages frequently are sweetened, reducing the effect of the bitter-taste receptor, he and his colleagues point out in their current paper.
Russell Keast, a professor of sensory and food sciences at Deakin University in Australia, issued a statement with a press release accompanying the article.
"The link between genetic variations in receptors and taste is an area of growing importance," he said. Keast was not involved with the current study.
"However, it does get more complex because alcoholic beverages contain flavors and tastes that may mask any aversive effects of bitterness - for example, the sweetness of a sherry, or the aromas of a cocktail."
Hayes stressed that people can make their own choices despite their genetics.
"Some individuals may learn to overcome their innate aversions to bitterness and consume excessive amounts of alcohol," he said, "while others who do not experience heightened bitterness may still choose not to consume alcohol for myriad reasons unrelated to taste."