Oral Perceptions of Fat and Taste Stimuli Are Modulated by Affect and Mood Induction

Petra Platte,Cornelia Herbert,Paul Pauli,Paul A S Breslin

doi:10.1371/journal.pone.0065006

Abstract

This study examined the impact of three clinical psychological variables (non-pathological levels of depression and anxiety, as well as experimentally manipulated mood) on fat and taste perception in healthy subjects. After a baseline orosensory evaluation, ‘sad’, ‘happy’ and ‘neutral’ video clips were presented to induce corresponding moods in eighty participants. Following mood manipulation, subjects rated five different oral stimuli, appearing sweet, umami, sour, bitter, fatty, which were delivered at five different concentrations each. Depression levels were assessed with Beck’s Depression Inventory (BDI) and anxiety levels were assessed via the Spielberger’s STAI-trait and state questionnaire. Overall, subjects were able to track the concentrations of the stimuli correctly, yet depression level affected taste ratings. First, depression scores were positively correlated with sucrose ratings. Second, subjects with depression scores above the sample median rated sucrose and quinine as more intense after mood induction (positive, negative and neutral). Third and most important, the group with enhanced depression scores did not rate low and high fat stimuli differently after positive or negative mood induction, whereas, during baseline or during the non-emotional neutral condition they rated the fat intensity as increasing with concentration. Consistent with others’ prior observations we also found that sweet and bitter stimuli at baseline were rated as more intense by participants with higher anxiety scores and that after positive and negative mood induction, citric acid was rated as stronger tasting compared to baseline. The observation that subjects with mild subclinical depression rated low and high fat stimuli similarly when in positive or negative mood is novel and likely has potential implications for unhealthy eating patterns. This deficit may foster unconscious eating of fatty foods in sub-clinical mildly depressed populations.

Highlights

The human gustatory system varies within subjects in its responsiveness to stimulation as a function of several biologically relevant variables including: time of day [1], hunger and nutritional state [2], eating habits [3], age [4], hormonal status [5], pregnancy [6], and neurotransmitter/organic psychological disorders [7,8]
Recent studies suggest that fatty acids stimulate taste receptor cells and humans with genetic variants in their fatty acid transporter CD36 differ in their ability to detect fatty acids [10,11,12,13]
A one way repeated measures Analysis of Variance (ANOVA) revealed for Positive Affect (PA) a significant main effect of mood manipulation (F(2,78) = 40.1, p,0.001)

Summary

Introduction

The human gustatory system varies within subjects in its responsiveness to stimulation as a function of several biologically relevant variables including: time of day [1], hunger and nutritional state [2], eating habits [3], age [4], hormonal status [5], pregnancy [6], and neurotransmitter/organic psychological disorders [7,8]. Recent studies suggest that fatty acids stimulate taste receptor cells and humans with genetic variants in their fatty acid transporter CD36 differ in their ability to detect fatty acids [10,11,12,13]. Patients with major clinical depression have elevated thresholds for sugars (were less sensitive) [15,16] Thresholds in these patients return to pre-depression levels after clinical recovery. Whereas it is unclear why depression affects taste thresholds, it may alter the neural pharmacology of taste or change the cognitive decision biases that results in higher threshold outcomes (or both) [17]

Methods

Results

Conclusion