How much you drink might be as much to do with your genes as your willpower, according to a new study.

People perceive tastes differently, and this is partly controlled by inherited factors. “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”, says Valerie Duffy at the Unversity of Connecticut (CBS News, 15 November 2004). As people who taste bitterness strongly are the least likely to enjoy alcohol, Duffy tested whether there is also a genetic basis for drinking habits.

Her group tested the reaction of 84 volunteers to the bitter chemical 6-n-propylthiouracil (PROP). They then looked at genetic variation among this group in the gene TAS2R38, which encodes a bitter-taste receptor. Two variants, PAV and AVI, were found among the study group, and the response to PROP corresponded to which combination of the two an individual carried. PAV/PAV individuals were the most sensitive to bitterness (“supertasters”), while those with two AVI variants were the least sensitive (“non-tasters”).

Duffy also saw a similar correlation with the amount of alcohol that the volunteers reported drinking: “People who tasted the least bitterness from PROP or who were TAS2R38 non-tasters consumed more alcohol than those who tasted the most bitterness from PROP or who were TAS2R38 tasters” (Daily Mail, 15 November 2004).

Dennis Drayna, who discovered TAS2R38, believes this is an important step in understanding drinking problems: “It is well known that there are genetic influences on alcoholism, but it is a very difficult tangle of facts. That taste appears to be so clear a factor is very exciting” (New Scientist, 15 November 2004).