Differential Perception of Caffeine Bitter Taste Depending on Smoking Status

Abstract

Taste impairment may be associated with tobacco smoking. We assessed taste recognition and intensity among healthy middle-aged current smokers (N = 94, 21 %), former smokers (N = 48, 11 %) and non-smokers (N = 309, 69 %) recruited on a voluntary basis among hospital staff. By means of a whole-mouth gustatory test, participants tasted one concentration of the four basic tastes (NaCl 34 mM, sucrose 58 mM, acetic acid 60 mM, caffeine 1.5 mM for salty, sweet, sour and bitter tastes, respectively) and completed a questionnaire for taste recognition and intensity (ranging from 0 to 10). The recognition of salty, sweet and sour tastes was not influenced by smoking status. Bitter taste recognition was wrong among 13.4, 19.8 and 26.5 % of non-smokers, current smokers and former smokers, respectively (p = 0.043). The adjusted odds ratio (95 % confidence interval) of correct bitter taste recognition was 0.31 (0.14–0.69) among former and 0.74 (0.35–1.55) among current smokers (p = 0.016), compared to non-smokers while adjusting for gender, age, year of assessment and bitter taste intensity. The distribution of caffeine’s bitter taste intensity was bimodal regardless of the smoking status. The differential perception of caffeine’s bitter taste by current and former smokers is likely to be caused by a toxic process. As taste impairment persists in former smokers, the bioaccumulation of some tobacco/combustion products might be responsible for the disequilibrium in taste buds regeneration.