An Investigation of TAS2R38 Haplotypes, Dietary Intake, and Risk Factors for Chronic Disease in the Canadian Longitudinal Study on Aging.

BACKGROUND: Variation in common taste receptor type 2 member 38 (TAS2R38) haplotypes is associated with bitter-taste sensitivity, but associations with dietary intake and risk factors for chronic disease are inconsistent. OBJECTIVES: To determine whether common TAS2R38 haplotypes are associated with dietary intake and risk factors for chronic disease using cross-sectional data from the Canadian Longitudinal Study on Aging (n = 26,090). Outcomes were assessed among the full sample and stratified by sex. METHODS: Taster status was determined from TAS2R38 haplotypes, and the respondents were classified as supertasters, tasters, and nontasters. Primary outcome variables were the consumption frequencies of vegetables, sweet-tasting foods, alcoholic beverages, and visceral adiposity index (VAI). Secondary outcome variables were the individual VAI components. Multivariable regression models adjusted for sociodemographic and lifestyle factors were used to assess associations between the taster status and outcome variables. RESULTS: Among the sample, 5655, 12,821, and 7614 respondents were classified as supertasters, tasters, and nontasters, respectively. Vegetable consumption was significantly higher among nontasters than among supertasters (1.23 ± 0.26 and 1.20 ± 0.22, respectively, P = 0.02). Among males, the consumption of sweet-tasting foods (0.40 ± 8.80 and 0.38 ± 7.55, P = 0.02) and green salad (0.35 ± 0.31 and 0.33 ± 0.27, P = 0.02) was also higher for nontasters than supertasters. Nontasters were more likely to be regular alcohol consumers compared with supertasters among the full sample (odds ratio [95% confidence interval]: 1.12 [1.03, 1.22]; P = 0.01) and among females (OR: 1.13; 95% CI: 1.01, 1.27; P = 0.04). No significant associations were observed between TAS2R38 haplotypes and VAI, although high-density lipoprotein cholesterol was significantly lower among supertasters than nontasters (1.45 ± 0.59 and 1.47 ± 0.63, respectively; P = 0.04). CONCLUSIONS: Among middle- to older-aged adults, minor associations are observed between TAS2R38 haplotypes, dietary intake, and high-density lipoprotein cholesterol. Genetic predisposition to bitter-taste sensitivity is linked to diet; however, further research is needed to understand the relevance for chronic disease risk.

Common variants in the CD36 gene are associated with dietary fat intake, high-fat food consumption and serum triglycerides in a cohort of Quebec adults.

BACKGROUND: The CD36 gene is a candidate for sensory detection of fatty acids and has been associated with individual differences in fat preferences and consumption. Excess adiposity may compromise sensory detection, but few studies have examined whether associations between CD36 variants and fat consumption differ between underweight/normal weight (UW/NW) and overweight/obese (OW/OB) individuals. METHODS: Diet (assessed by food frequency questionnaire), genetic (nine variants), body mass index (BMI), lifestyle and biomarker data were obtained from the CARTaGENE biobank (n = 12,065), a Quebec cohort of middle-aged adults. Primary outcome variables included intakes (%kcal/day) of total, saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. Secondary outcome variables included consumption (servings/day) of four food categories with high-fat content (added fats and oils, high-fat foods, desserts and MUFA- and PUFA-rich foods) and biomarkers of chronic disease. Multivariable regression models stratified by BMI category were used to assess associations between CD36 variants and outcome variables. RESULTS: Among UW/NW, rs1049654 and rs10499859 were associated with higher intakes of total fat, MUFA and PUFA (all P < 0.05), while rs1527483 and rs3211956 were associated with higher SFA (P = 0.0278) and lower PUFA (P = 0.0466) intake, respectively. Rs1527483 and rs3211956 were also associated with higher consumption of high-fat foods and desserts (all P < 0.05). Among OW, rs1054516 and rs3173798 were associated with higher SFA intake (both P < 0.05), and rs1054516 was also associated with higher serum triglycerides (P = 0.0065). CONCLUSIONS: CD36 variants are associated with habitual fat consumption, which may play a role in subsequent associations with chronic-disease biomarkers. Associations differ by BMI status and dietary fat type.

TAS2R38 haplotypes, COVID-19 infection, and symptomatology: a cross-sectional analysis of data from the Canadian Longitudinal Study on Aging.

The TAS2R38 gene is well known for its function in bitter taste sensitivity, but evidence also suggests a role in innate immunity. TAS2R38 may be relevant in coronavirus disease 2019 (COVID-19), but research findings are inconsistent. The objective of this study was to explore whether common TAS2R38 haplotypes are associated with COVID-19 infection and symptomatology in the Canadian Longitudinal Study on Aging (CLSA). Data from the CLSA COVID-19 Questionnaire and Seroprevalence sub-studies were utilized with CLSA genetic data for common TAS2R38 haplotypes related to bitter taste sensitivity. Haplotypes were categorized into three diplotype groups: [P]AV homozygotes, [P]AV/[A]VI heterozygotes, and [A]VI homozygotes. No significant differences were observed between diplotypes and COVID-19 infection frequency. Among self-reported COVID-19 cases (n = 76), and in uncorrected exploratory analyses, heterozygotes were less likely to report experiencing sinus pain compared to [P]AV homozygotes. Among seroprevalence-confirmed cases (n = 177), [A]VI homozygotes were less likely to report experiencing a sore/scratchy throat compared to [P]AV homozygotes. However, both observations were non-significant upon correction for multiple testing. In this study, TAS2R38 haplotypes were not significantly associated with COVID-19 infection or symptomatology. Nevertheless, in light of some exploratory patterns and conflicting evidence, additional research is warranted to evaluate links between TAS2R38 and innate immunity.