What makes beer taste so darn good to men, but vile to most women? Some oral sensations are under genetic control and new research suggests that these influences on taste perception could help determine the risk of excess alcohol consumption.
A study in the November issue of Alcoholism: Clinical & Experimental Research examines associations between a newly discovered taste receptor gene (TAS2R38), perceived intensity of a bitter compound called 6-n-propylthiouracil (PROP), and perceived intensity of alcohol. Findings reveal that both bitter taste perception and genotype make overlapping and independent contributions to oral sensations from alcohol and alcohol intake.
"We do not all share the same oral sensory experiences from foods and beverages," said Valerie B. Duffy, a registered dietitian, associate professor in the School of Allied Health at the University of Connecticut, and first author of the study. "Some of the differences in oral sensation are under genetic control, and these differences can explain some of the variability in what we like and ultimately choose to eat and drink." She added that genetic variation in taste is a normal variation; it does not imply that some people are taste dysfunctional and others are not.
"It's about time that individual differences in taste perception have been considered in research since there are wide individual differences in the liking for the taste of alcohol," said Julie A. Mennella, a biopsychologist at Monell Chemical Senses Center. "Our sense of taste, along with the sense of smell, plays an important role in determining what foods and beverages we accept or reject. They are also our senses of pleasure."
Duffy explained that one measure for taste genetics is the bitterness of PROP. "Individuals who cannot taste the bitterness of PROP, or taste the bitterness of PROP as weak, are called nontasters. Those who taste the most bitterness are called supertasters. Previous research has found that PROP nontasters experience more positive, such as sweetness, and less negative, such as bitterness, irritation or astringency, sensations from alcoholic beverages and thus may be more likely to drink alcoholic beverages. Conversely, PROP supertasters have a sensory hindrance to consuming alcoholic beverages, because alcoholic beverages elicit more negative, such as bitterness or irritation, and less positive, such as sweetness, oral sensations."
Study participants (53 females, 31 males), primarily light and moderate drinkers, rated the bitterness of five PROP concentrations (0.032 - 3.2 mM). They were interviewed about how frequently during a year they consumed beer, wine, wine coolers, and liquor. Researchers also drew blood for genotyping from all participants in order to determine if the gene TAS2R38 – which provides the blueprint for a protein that forms a receptor that allows individuals to taste bitter chemicals like PROP – could predict PROP bitterness, alcohol sensations, and alcohol intake. Taste papillae on the anterior tongue (fungiform papillae) were also counted.