title: Influence of caffeine on the liking of novel-flavored soda in adolescents.
abstract: BACKGROUND
  Soda manufacturers claim that caffeine is added to soda as a flavor enhancer, but many researchers have speculated that caffeine is added to increase the hedonic and reinforcing properties of the soda. Studies in adults have demonstrated that caffeine can condition flavor preferences when added to novel-flavored beverages.
  
  
  OBJECTIVE
  The purpose of this study was to test the hypothesis that caffeine added to novel-flavored drinks would increase liking and preference in adolescents.
  
  
  METHODS
  Adolescents (n = 99) between the ages of 12 and 17 rated and ranked seven novel soda drinks. They were then randomly assigned to consume one of these beverages paired with either caffeine (1 or 2 mg/kg) or placebo over four consecutive days and rate liking. On the final visit, participants retasted the seven beverages and provided hedonic ratings and rankings.
  
  
  RESULTS
  Participants in the 2-mg/kg caffeine group increased the liking of the beverage over the exposure period after an initial decrease, but there was no change in liking for those in the placebo group or in the 1-mg/kg group. The increase in liking in the 2-mg/kg group was accompanied by a decrease in perceived bitterness, but no change in beverage ranking or consumption during the post-test.
  
  
  CONCLUSIONS
  Caffeine added to novel beverages results in a decrease in liking followed by an increase in liking with repeated exposures that may result from habituation to the bitterness of caffeine. Change in bitter perception may be the mechanism by which adolescents establish regular caffeine use.
authors.affiliation: Nutrition and Health Research Laboratory, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, 3435 Main Street, 15 Farber Hall, Buffalo, NY 14214, USA. jltemple@buffalo.edu
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Temple
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Ziegler
authors.forename: Adam
authors.initials: A
authors.lastname: Graczyk
authors.forename: Ashley
authors.initials: A
authors.lastname: Bendlin
authors.forename: Shannon
authors.initials: S
authors.lastname: O'Leary
authors.forename: Yasemin S
authors.initials: YS
authors.lastname: Schnittker
mesh_terms: D000293:Adolescent; D001628:Beverages; D002110:Caffeine / Q000008:administration & dosage*; D002648:Child; D004311:Double-Blind Method; D005260:Female; D005518:Food Preferences; D006801:Humans; D008297:Male; D012054:Reinforcement, Psychology; D013649:Taste
chemical_list: D002110:Caffeine