Study of relationships between taste receptor gene (TAS1R2) polymorphism rs4920566 and sugar sensitivity and food preference of sweet products

BACKGROUND: Increased consumption  of sweet and high-calorie foods leads to weight gain in humans and the development of metabolic syndrome. Great attention is given to a personalized approach to nutrition correction based on genetic testing. The genetic basis for human taste sensitivity to sweet stimuli remains is understudied. The role of the g.18853330 A>G (rs4920566) polymorphism of the TAS1R2 gene in preference for sweets has not been fully studied.AIM: To investigate the possible relationship between rs4920566 polymorphism  in TAS1R2 gene and sensitivity to natural sugars and food preference of high-calorie sweet foods in humans.MATERIALS AND METHODS: A single-sample experimental study was carried out. The study participants were conditionally healthy students who voluntarily agreed to conduct it. Sugar sensitivity was assessed in two tasting tests. Sucrose sensitivity thresholds (STS) were determined by staircase procedure (solutions: 8.0 to 500 mM/l). To assess food preferences for sweet foods, specially designed questionnaires with a checklist of products were used. Genomic DNA samples from all study participants were obtained from buccal epithelial cells. Genomic DNA was extracted from buccal epithelial cells using the adsorption of DNA with an inorganic sorbent in the presence of a chaotropic agent. Typing of the rs4920566 polymorphism in TAS1R2 gene was performed using asymmetric real-time PCR.RESULTS: The study included  26 young  men and 110 young  women which the average age was 20.8±4.8 (SD) years. Gender  was  a  significant  factor  affecting  the  taste  perception  of  the  sweetness  sugars  (maltose,  glucose,  sucrose and fructose) in students. Young  men more often than young  women  could  not distinguish  the taste of four sugars (β=-2.93(0.99), p=0.003). The rs4920566 polymorphism in TAS1R2 gene did not affect the ability of students to distinguish the taste of four natural sugars. It was found that the variation series of STS values for sucrose in young women with the A allele (16.0[16.0–31.0] versus 16.0[8.0–16.0] mmol/l, pcor=0.002) and A/G genotype  (16.0[16.0–31.0] vs. 16.0[8.0–16.0] mmol/l, pcor=0.010) were significantly  lower compared to young men. Separately, in young women with the G/G genotype the range of STS is shifted towards higher concentrations of sucrose compared with women with the A/G genotype (16.0[16.0–31.0] vs. 16.0[8.0 -16.0] mmol/l, pcor=0.039). Testing the hypothesis about the randomness of the relationship between the rs4920566 genotypes  of the TAS1R2 gene and the liking rating of foods with a sweet taste using Kruskal-Wallis test did not allow us to conclude that the A/A, A/G and G/G genotypes of the TAS1R2 gene influence the choice of sugary high-calorie foods in students.CONCLUSION: Our results are consistent with the literature data and confirm that rs4920566 polymorphism of TAS1R2 gene cannot be an informative marker for the diagnosis of metabolic conditions associated with the consumption of high-calorie sweet foods. Likely, its functions are related to the mechanisms of neurotransduction of the sweet taste signal.