Variation in the TAS1R2 Gene, Sweet Taste Perception and Intake of Sugars.

BACKGROUND/AIMS: To determine whether variation in the TAS1R2 gene affects sucrose taste perception and sugar intake. METHODS: Participants were men (n = 238) and women (n = 458) aged 20-29 years. A subset (n = 95) with body mass index (BMI) data available completed a sensory analysis study. A food frequency questionnaire assessed dietary intake, and eight polymorphisms were genotyped (rs12033832, rs12137730, rs35874116, rs3935570, rs4920564, rs4920566, rs7513755 and rs9701796). Sucrose taste thresholds were determined by staircase procedure (solutions: 9 × 10-6 to 0.5 mol/l). Suprathreshold sensitivity to 0.01-1.0 mol/l sucrose solutions was assessed using general Labeled Magnitude Scales. RESULTS: A significant genotype-BMI interaction was observed for rs12033832 (G>A) for suprathreshold sensitivity (p = 0.01) and sugar intake (p = 0.003). Among participants with a BMI ≥25, G allele carriers had lower sensitivity ratings (mean incremental area under the taste sensitivity curve ± SE; GG/GA 54.4 ± 4.1 vs. AA 178.5 ± 66.6; p = 0.006), higher thresholds (GG/GA 9.3 ± 1.1 vs. AA 4.4 ± 4.3 mmol/l; p = 0.004) and consumed more sugars (GG/GA 130 ± 4 vs. AA 94 ± 13 g/day; p = 0.009). G allele carriers with a BMI <25 had lower thresholds (GG/GA 8.6 ± 0.5 vs. AA 16.7 ± 5.7 mmol/l; p = 0.02) and consumed less sugars (GG/GA 122 ± 2 vs. AA 145 ± 8 g/day; p = 0.004). CONCLUSION: The rs12033832 single nucleotide polymorphism in TAS1R2 is associated with sucrose taste and sugar intake, but the effect differs depending on BMI.

Genetic variation in putative salt taste receptors and salt taste perception in humans.

The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in the SCNN1A (3), SCNN1B (12), SCNN1G (6), and TRPV1 (10) genes affect salt taste perception. Participants were men (n = 28) and women (n = 67) from the Toronto Nutrigenomics and Health study aged 21-31 years. Taste thresholds were determined using a 3-alternative forced-choice staircase model with solutions ranging from 9×10(-6) to 0.5 mol/L. Suprathreshold taste sensitivity to 0.01-1.0 mol/L salt solutions was assessed using general labeled magnitude scales. None of the SNPs in the SCNN1A and SCNN1G genes were significantly associated with either outcome. In the SCNN1B gene, 2 SNPs in intronic regions of the gene modified suprathreshold taste sensitivity (mean iAUC ± SE). Those homozygous for the A allele of the rs239345 (A>T) polymorphism and the T allele of the rs3785368 (C>T) polymorphism perceived salt solutions less intensely than carriers of the T or C alleles, respectively (rs239345: 70.82±12.16 vs. 96.95±3.75, P = 0.02; rs3785368: 57.43±19.85 vs. 95.57±3.66, P = 0.03) In the TRPV1 gene, the rs8065080 (C>T, Val585Ile) polymorphism modified suprathreshold taste sensitivity where carriers of the T allele were significantly more sensitive to salt solutions than the CC genotype (98.3±3.8 vs. 74.1±8.3, P = 0.008). Our findings show that variation in the TRPV1 and the SCNN1B genes may modify salt taste perception in humans.