Taste Perception And Sweet Taste Preference In Type-2 Diabetic Subjects: Genomic And Metabolomic Factors Involved

Background: Taste perception and preferences are important determinants of dietary intake, contributing to cardiovascular risk factors. In diabetics, a taste impairment (mainly for sweet taste), has been reported with inconsistent results. Moreover, taste preference is another poorly investigated factor. Objective: To evaluate the gustatory function and taste preferences of type- 2 diabetics in comparison to non-diabetics, and to investigate novel genes and selected metabolites related to sweet taste preference. Methods: We analyzed 425 subjects with metabolic syndrome (55-75 years) and 38% diabetics. Subjects completed a hedonic test for taste preference (sweet, salty, sour, umami and bitter), and 348 participants performed taste perception tests challenging subjects with solutions of prototypical tastants (sucrose, NaCl, citric acid, glutamate and PTC). A “total taste score” was computed. A Genome-wide association study (GWAS) for sweet preference was undertaken, and serum metabolites were determined by proton nuclear magnetic resonance spectroscopy. Results: Sweet taste perception was lower diabetic subjects without reaching statistically significant results (P=0.18). However significant differences were observed for bitter (P=0.024). Likewise “total taste score” was significantly lower in diabetics (P=0.034). Interestingly, in terms of taste preferences, only statistically significant results were obtained for the sweet taste (P=0.021, higher in diabetics). We identified metabolites associated with higher sweet taste preference and lower sweet taste perception (i.e. cholines; P<0.05), as well as novel genes statistically associated with sweet taste preference at the GWAS level (i.e. the PTPRN2 gene; P<5x10-8). Conclusions: We identified new genes and metabolites associated with sweet taste perception and characterized differences by type-2 diabetes.