Chemosensory Sensitivity after Coffee Consumption Is Not Static: Short-Term Effects on Gustatory and Olfactory Sensitivity

Abstract

Chemosensory sensitivity has great variation between individuals. This variation complicates the chemosensory diagnostics, as well as the creation of a meal with universally high hedonic value. To ensure accurate characterization of chemosensory function, a common rule of thumb is to avoid food/beverages one hour before chemosensory testing. However, the scientific foundation of this time of fast remains unclear. Furthermore, the role of coffee on immediate chemosensitivity is not known and may have implications for optimization of gastronomy and hedonia. The aim of this study is to investigate the modularity effects of coffee consumption on immediate gustatory and olfactory sensitivity. We included 155 participants. By applying tests for olfactory and gustatory sensitivity before and after coffee intake, we found no changes in olfactory sensitivity, but significantly altered sensitivity for some basic tastants. We repeated our experimental paradigm using decaffeinated coffee and found similar results. Our results demonstrate that coffee (regular and decaffeinated) alters the subsequent perception of taste, specifically by increasing the sensitivity to sweet and decreasing the sensitivity to bitter. Our findings provide the first evidence of how coffee impacts short-term taste sensitivity and consequently the way we sense and perceive food following coffee intake—an important insight in the context of gastronomy, as well as in chemosensory testing procedures.

Impact of Nutritional Intervention on Taste Perception—A Scoping Review

“…Interestingly, in both groups of healthy participants the detection threshold for the sweet tastant was increased (p < 0.001) while the threshold for the bitter tastant was significantly decreased (p < 0.001). However, the decrease of the threshold for the bitter tastant was found to be larger in participants that did not consume coffee daily [44].…”

“…The main tastants investigated were fatty acids [21,22,42,52,53], salt [40,49,51], sugar [43,47,50], zinc [41], alcohol [39], and glutamate [45]. Basic tastants (salty, sour, sweet and bitter) evaluation was instead performed in the only two studies evaluating on healthy volunteers the impact of fasting [46,48] and of two different types of coffee [44]. The taste tests investigated, with different techniques and tastants concentrations, the detection threshold [21,39,42,44,46,47,[49][50][51][52][53]; the recognition threshold [40,44,48,49]; the intensity rating [22,[39][40][41]43,45,47]; and the preference [40,43] (Tables 2 and 3).…”

“…Basic tastants (salty, sour, sweet and bitter) evaluation was instead performed in the only two studies evaluating on healthy volunteers the impact of fasting [46,48] and of two different types of coffee [44]. The taste tests investigated, with different techniques and tastants concentrations, the detection threshold [21,39,42,44,46,47,[49][50][51][52][53]; the recognition threshold [40,44,48,49]; the intensity rating [22,[39][40][41]43,45,47]; and the preference [40,43] (Tables 2 and 3). Significant changes in these domains were found especially in those studies in which the nutritional intervention, dietary habits or preferences, and interventional approach on the meal load specifically encompassed the tastants included in the taste test [20,21,39,44,51].…”

“…Twelve studies were performed by testing taste after an interventional approach (Table 3): 6 of which enrolled only healthy subjects [43][44][45][46][47][48] and 6 which also included patients affected by different disorders [21,[49][50][51][52][53].…”

“…Other authors further reduced the time length of nutrients administration or deprivation to evaluate fast taste changes. This is the case of a very short-term protocol, in which the recognition threshold for sweet, sour, salty, and bitter tastants was evaluated immediately before and after the consumption of the same blend of regular or decaffeinated coffee [44]. Interestingly, in both groups of healthy participants the detection threshold for the sweet tastant was increased (p < 0.001) while the threshold for the bitter tastant was significantly decreased (p < 0.001).…”