The effect of repeated exposure to fruit drinks on intake, pleasantness and boredom in young and elderly adults.

The effect of a repeated monotonous exposure on ad libitum intake, pleasantness and boredom in elderly people in a real life situation is unclear. We therefore investigated the effects of repeated exposure to ad libitum intake of three orange-based drinks on boredom and acceptance in young and elderly people. Young (n=32) and elderly women (n=36) participated in a randomized within subjects cross over trial with three intervention periods of 12 days each followed by a 2-day wash out period. During each intervention period, the participants received 1 L of one type of drink per day. The three drinks varied in sweetness intensity. Intake was measured by weighing the returned packets and pleasantness, boredom and sweetness were rated on a 10-point scale. For the young women, mean consumption of the three drinks (p<0.01) and pleasantness decreased (p<0.01) and boredom increased (p<0.001). For the elderly women, consumption increased (p=0.03) whereas pleasantness (p=0.34) and boredom (p=0.40) were stable. In the young women, the orange peach drink which had the highest sugar content contributed the most to the effect of the repeated exposure. The consumption and pleasantness ratings for this drink decreased (r=-1.05, p=0.01 and r=-0.07, p=0.007, respectively) and boredom increased (r=0.12, p<0.001). In conclusion, elderly women experienced no increased boredom whereas young women did.