Single nucleotide polymorphisms in sweet, fat, umami, salt, bitter and sour taste receptor genes are associated with gustatory function and taste preferences in young adults.

Taste is a fundamental mechanism whereby compounds are detected orally, yet it is highly variable among individuals. The variability in taste that is attributable to genetics is not well-characterized despite its potential role in food selection, and therefore, eating habits that contribute to risk of overweight and obesity. In order to implicate measures of taste function and preference as potentially deterministic factors in adverse eating behaviors that lead to obesity, it must be shown that a relationship exists between genetic variation in taste receptor genes and psychophysical measures of taste in the absence high body mass index. The primary objective of this pilot study was to investigate the relationship between single nucleotide polymorphisms (SNPs) in taste receptor genes and 3 different psychophysical measures of taste in healthy young adults. Sweet, salt, umami, fat, sour, and bitter taste receptor gene SNPs were genotyped in 49 participants (ages 24.6 ± 0.6 years) who completed testing to determine oral detection threshold (DT), suprathreshold sensitivity (ST) and taste preference (PR). A simultaneous association test was conducted between each SNP and the 3 taste outcomes (DT, ST, and PR). Twelve SNPs were associated with at least one of the 3 taste outcomes. Associations were observed between SNPs in taste receptor genes and psychophysical measures of sweet, fat, umami, and salt taste. These results suggest that differences in interindividual psychophysical measures of tastes, namely DT, ST, and PR, may be partially attributed to genetic variation in taste receptor genes. Future studies are warranted to investigate if these findings have consequences for habitual dietary intake of foods that elicit these tastes.

Taste Sensitivity and Taste Preference Measures Are Correlated in Healthy Young Adults.

Taste is fundamentally important for food selection. Although measures of taste sensitivity and preference have been refined over several decades, it remains largely unknown how these measures relate to each other and to food preferences. The objectives of this study were to examine, in healthy adults (age 24.6 ± 0.6 years, n = 49), 1) correlations among measures of taste sensitivity, including detection threshold (DT) and suprathreshold sensitivity (ST), and taste preference (PR) within sweet, salt, sour, umami, and [...] fat tastes; and 2) underlying associations [...] among DT, ST, and PR measurements using principal component analysis. DTs and STs were negatively correlated within each taste modality. Salt, sweet, and umami DTs and STs were positively and negatively correlated with PRs, respectively. No correlations were observed between sour and fat DTs, STs, and PRs. Two principal components accounted for 41.9% of the variance and produced 3 clear clusters consisting of DTs, STs, or PRs from each taste modality. Sweet PR and fat ST deviated from the clusters and may, therefore, be driven by different factors. No associations were observed between measured PR and ST with self-reported food PRs. Overall, this study provides evidence that higher sensitivities only to salt, sweet, or umami taste are associated with a decrease in the PR for these tastes. These findings demonstrate the importance of investigating taste sensitivity together with PR to gain a more complete understanding of the determinants of food selection.

The Relationship between Single Nucleotide Polymorphisms in Taste Receptor Genes, Taste Function and Dietary Intake in Preschool-Aged Children and Adults in the Guelph Family Health Study.

Taste is a fundamental determinant of food selection, and inter-individual variations in taste perception may be important risk factors for poor eating habits and obesity. Characterizing differences in taste perception and their influences on dietary intake may lead to an improved understanding of obesity risk and a potential to develop personalized nutrition recommendations. This study explored associations between 93 single nucleotide polymorphisms (SNPs) in sweet, fat, bitter, salt, sour, and umami taste receptors and psychophysical measures of taste. Forty-four families from the Guelph Family Health Study participated, including 60 children and 65 adults. Saliva was collected for genetic analysis and parents completed a three-day food record for their children. Parents underwent a test for suprathreshold sensitivity (ST) and taste preference (PR) for sweet, fat, salt, umami, and sour as well as a phenylthiocarbamide (PTC) taste status test. Children underwent PR tests and a PTC taste status test. Analysis of SNPs and psychophysical measures of taste yielded 23 significant associations in parents and 11 in children. After adjusting for multiple hypothesis testing, the rs713598 in the TAS2R38 bitter taste receptor gene and rs236514 in the KCNJ2 sour taste-associated gene remained significantly associated with PTC ST and sour PR in parents, respectively. In children, rs173135 in KCNJ2 and rs4790522 in the TRPV1 salt taste-associated gene remained significantly associated with sour and salt taste PRs, respectively. A multiple trait analysis of PR and nutrient composition of diet in the children revealed that rs9701796 in the TAS1R2 sweet taste receptor gene was associated with both sweet PR and percent energy from added sugar in the diet. These findings provide evidence that for bitter, sour, salt, and sweet taste, certain genetic variants are associated with taste function and may be implicated in eating patterns. (Support was provided by the Ontario Ministry of Agriculture, Food, and Rural Affairs).

Guelph Family Health Study: pilot study of a home-based obesity prevention intervention.

OBJECTIVE: To examine the feasibility and preliminary impact of a home-based obesity prevention intervention among Canadian families. METHODS: Families with children 1.5-5 years of age were randomized to one of three groups: (1) four home visits (HV) with a health educator, emails, and mailed incentives (4HV; n = 17); (2) two HV, emails, and mailed incentives (2HV; n = 14); or (3) general health advice through emails (control; n = 13). Parents randomized to the 2HV and 4HV groups completed post-intervention satisfaction surveys. At baseline and post-intervention, parents reported frequency of family meals and their children's fruit, vegetable, and sugar-sweetened beverage (SSB) intake. We assessed the children's physical activity, sedentary behaviour, and sleep using accelerometers and their % fat mass using bioelectrical impedance analysis. Differences in outcomes at post-intervention, controlling for baseline, were examined using generalized estimating equations. RESULTS: Of the 44 families enrolled, 42 (96%) had 6-month outcome data. Satisfaction with the intervention was high; 80% were "very satisfied" and 20% were "satisfied." At post-intervention, children randomized to the 4HV and 2HV groups had significantly higher fruit intake and children randomized to the 2HV group had significantly lower percentage of fat mass, as compared to the control. No significant intervention effect was found for frequency of family meals, the children's vegetable or SSB intake, physical activity, sedentary behaviour, or sleep. CONCLUSIONS: Our results suggest that the delivery of a home-based intervention is feasible among Canadian families and may lead to improved diet and weight outcomes among children. A full-scale trial is needed to test the effectiveness of this home-based intervention. CLINICAL TRIALS REGISTRATION NUMBER: NCT02223234.

Single Nucleotide Polymorphisms in Taste Receptor Genes Are Associated with Snacking Patterns of Preschool-Aged Children in the Guelph Family Health Study: A Pilot Study.

Snacking is an integral component of eating habits in young children that is often overlooked in nutrition research. While snacking is a substantial source of calories in preschoolers' diets, there is limited knowledge about the factors that drive snacking patterns. The genetics of taste may help to better understand the snacking patterns of children. The rs1761667 single nucleotide polymorphism (SNP) in the CD36 gene has been linked to fat taste sensitivity, the rs35874116 SNP in the TAS1R2 gene has been related to sweet taste preference, and the rs713598 SNP in the TAS2R38 gene has been associated with aversion to bitter, green leafy vegetables. This study seeks to determine the cross-sectional associations between three taste receptor SNPs and snacking patterns among preschoolers in the Guelph Family Health Study. Preschoolers' snack quality, quantity, and frequency were assessed using three-day food records and saliva was collected for SNP genotyping (n = 47). Children with the TT genotype in TAS1R2 consumed snacks with significantly more calories from sugar, and these snacks were consumed mostly in the evening. Total energy density of snacks was highest in the CC and CG genotypes compared to the GG genotype in TAS2R38, and also greater in the AA genotype in CD36 compared to G allele carriers, however this difference was not individually attributable to energy from fat, carbohydrates, sugar, or protein. Genetic variation in taste receptors may influence snacking patterns of preschoolers.

A review of the associations between single nucleotide polymorphisms in taste receptors, eating behaviors, and health.

Food preferences and dietary habits are heavily influenced by taste perception. There is growing interest in characterizing taste preferences based on genetic variation. Genetic differences in the ability to perceive key tastes may impact eating behavior and nutritional intake. Therefore, increased understanding of taste biology and genetics may lead to new personalized strategies, which may prevent or influence the trajectory of chronic disease risk. Recent advances show that single nucleotide polymorphisms (SNPs) in the CD36 fat taste receptor are linked to differences in fat perception, fat preference, and chronic-disease biomarkers. Genetic variation in the sweet taste receptor T1R2 has been shown to alter sweet taste preferences, eating behaviors, and risk of dental caries. Polymorphisms in the bitter taste receptor T2R38 have been shown to influence taste for brassica vegetables. Individuals that intensely taste the bitterness of brassica vegetables ("supertasters") may avoid vegetable consumption and compensate by increasing their consumption of sweet and fatty foods, which may increase risk for chronic disease. Emerging evidence also suggests that the role of genetics in taste perception may be more impactful in children due to the lack of cultural influence compared to adults. This review examines the current knowledge of SNPs in taste receptors associated with fat, sweet, bitter, umami, and salt taste modalities and their contributions to food preferences, and chronic disease. Overall, these SNPs demonstrate the potential to influence food preferences and consequently health.