Correlation Between the TAS2R38 Genetic Polymorphism, PROP Perception and Eating Habits: A Cross-Sectional Molecular...

Background/Objectives: Genetic variation in bitter taste receptors, particularly TAS2R38, influences sensitivity to bitter compounds such as 6-n-propylthiouracil (PROP). However, its influence on food preferences and dietary habits remains unclear. This study investigated the relationship between TAS2R38 rs713598 polymorphism, a variant in strong linkage disequilibrium with other common variants and therefore served as a proxy for TAS2R38 bitter taste-related genetic variation, PROP responsiveness, food preferences, and adherence to the Mediterranean diet. Methods: A cross-sectional molecular epidemiological study was conducted on 200 Italian adults. Participants completed questionnaires assessing food preferences, Mediterranean diet adherence (energy-restricted Mediterranean Diet Adherence Screener; er-MEDAS), and physical activity (IPAQ). Bitter taste perception was evaluated using the PROP test and a Labelled Magnitude Scale. Saliva samples were collected for TAS2R38 rs713598 genotyping by qPCR. Associations were analysed using Spearman's correlation and generalised linear models. Results: Genotyping was completed for 176 participants. A significant positive correlation was found between rs713598 genotype and PROP sensitivity (ρ = 0.404, p < 0.01). Women showed higher PROP responsiveness than men. No significant associations were observed between PROP responsiveness or TAS2R38 genotype and either food preferences or Mediterranean diet adherence. Older age was associated with greater preference for bitter foods (p = 0.008), whereas higher physical activity and non-smoking status were associated with greater adherence to the Mediterranean diet (p = 0.020 and p = 0.024, respectively). Conclusions: TAS2R38 polymorphism influenced bitter taste perception but showed limited relevance for food preferences and dietary habits. Lifestyle factors appeared more influential in shaping dietary behaviour.