Sweet and bitter tastes of alcoholic beverages mediate alcohol intake in of-age undergraduates

Alcoholic beverages are complex stimuli, giving rise to sensations that promote or inhibit intake. Previous research has shown associations between 6-n-propylthiouracil (PROP) bitterness, one marker of genetic variation in taste, and alcohol behaviors. We tested the PROP bitterness and alcohol intake relationship as mediated by tastes of sampled alcoholic beverages. Forty-nine undergraduates (mean age=22 years) participated. According to the Alcohol Use Disorders Identification Test (AUDIT), only 3 of 49 subjects reported patterns indicating problematic drinking. Participants used the general Labeled Magnitude Scale to rate PROP bitterness and tastes from and preference for Pilsner beer, blended scotch whiskey, instant espresso and unsweetened grapefruit juice. Alcohol intake was reported over a typical week. Regression analysis tested the hypothesis that PROP bitterness influenced alcohol bitterness and sweetness, which in turn predicted alcohol intake. Those who tasted less PROP bitterness tasted all beverages as less bitter and more preferred. Sweetness of scotch was significantly greater in those who tasted PROP as least bitter. For scotch, greater sweetness and less bitterness from sampled scotch were direct predictors of greater alcohol intake. For beer, preference ratings were better predictors of alcohol intake than the bitter or sweet tastes of the sampled beer. These findings support that PROP bitterness predicts both positive and negative tastes from alcoholic beverages and that those tastes may predict alcohol intake. The college environment may attenuate direct effects of PROP bitterness and intake. Here, PROP bitterness does not predict alcohol intake directly, but acts instead through sweet and bitter tastes of alcoholic beverages.