Associations between Taste and Olfactory Function, Dietary Intake and Cardiovascular Risk Factors in Participants of the CoDiet Study

Background: Sensory perception may influence food-related behaviour and metabolic health, but its associations with dietary behaviour and more cardiometabolic characteristics remain incompletely understood. Objective: To investigate associations between objectively assessed olfactory and gustatory function, dietary behaviour, and cardiometabolic risk factors in participants of the CoDiet study. Methods: We have carried out a cross-sectional pilot study in 60 participants recruited at the University of Valencia within the multicentre CoDiet project. Data were collected at baseline from participants in Work Package 5 of the CoDiet. Olfactory function was assessed using the Sniffin' Sticks test and expressed as the Threshold-Discrimination-Identification (TDI) score. Gustatory function was assessed analysing Taste perception for bitter, salty, sweet, sour, and umami by rating different concentrations of prototypical tastants. The highest concentration (concentration V) was used (including PTC and PROP for bitter) and computing a total taste perception score for the 5 modalities. Taste preference and selected food preference were determined using a 10-point Likert scale. Dietary behaviour was assessed using a five-day dietary record, wearable camera-based verification, and a food frequency questionnaire. A validated 14-item scale was used to estimate the adherence to the Mediterranean diet (MedDiet). Associations were examined using correlation coefficients and further multivariable adjustment for potential confounders was considered. Results: An important variability in olfactory and gustatory function was detected in this population. Olfactory function was not significantly associated with dietary intake, food preferences, or taste preferences. More significant associations were detected for gustatory function. Taste preference was associated with food preference and food intake, mainly for sweet taste (p<0.05). Higher TDI scores were associated with lower BMI (ρ = −0.289, p = 0.025), waist circumference (ρ = −0.297, p = 0.021), and waist-to-hip ratio (ρ = −0.276, p = 0.033); the association with BMI remained significant after adjustment (ρ = −0.290, p = 0.027) and in multivariable regression (B = −0.255, 95% CI −0.449 to −0.062, p = 0.011). PROP and PTC scores were associated with higher body fat percentage before adjustment. Higher TDI was positively associated with HDL cholesterol, while higher PTC scores were associated with lower systolic blood pressure after adjustment for age and sex, and total PROP and PTC scores with triglycerides. Associations of PTC and total PTC with creatinine remained significant after adjustment. Sensory function was not associated with Mediterranean diet adherence. Conclusion: The association between sensory function, taste preferences, food preference, food intake and cardiometabolic risk factors is very complex. In this study, objectively assessed sensory function showed limited associations with habitual dietary behaviour but was associated with selected measures of body composition and cardiometabolic health. The most consistent finding was the inverse association between olfactory function and BMI. In terms of taste preferences, food preference and intake, we detected significant associations with the sweet taste. Given the pilot, exploratory, and cross-sectional design and the absence of multiple-comparison correction, findings should be interpreted cautiously as hypothesis-generating. Longitudinal studies with large sample size are needed. Keywords: olfactory function; gustatory function; sensory perception; dietary behaviour; body composition; cardiometabolic risk; obesity; Sniffin' Sticks; CoDiet