Bitter taste sensitivity, partly shaped by genetic variation in TAS2R38, the most extensively studied of the approximately 25 functional human bitter taste receptor genes, has long been proposed to shape food acceptance and dietary behaviour, yet no prior study has examined its association with validated, multidimensional eating behaviour or holistic diet quality in Australian adults, despite Australia’s distinct and culturally diverse food environment. This study provides the first such evidence, examining whether phenotypic bitter taste sensitivity, assessed as phenylthiocarbamide (PTC) taster status, is associated with diet quality, eating behaviour and body mass index (BMI) in a well-powered Australian sample. A total of n = 401 adults (75.1% female median age 44 years, IQR 31–60) were recruited via convenience sampling between August and December 2025 and completed a comprehensive online questionnaire, with data collected in person (n = 74) or remotely (n = 327). PTC taster status was determined using validated taste strips (tasters n = 206 non-tasters n = 195). Diet quality was measured using the Australian Recommended Food Score(1), a validated index of adherence to national dietary guidelines, and eating behaviour using the Adult Eating Behaviour Questionnaire(2), a multidimensional measure of appetitive traits. Associations were examined using ordinary least squares regression with heteroskedasticity-consistent standard errors, adjusting a priori for age, sex, education, income and smoking status, with false discovery rate correction applied across related domain-level and subscale outcomes to ensure robust inference. Tasters were significantly younger and more likely female than non-tasters (both p < 0.05). After adjustment and correction, no statistically significant associations emerged between taster status and diet quality (ARFS total β = -1.73, 95% CI -3.78 to 0.33, p = 0.10), any AEBQ composite or subscale, or BMI (β = 0.86 kg/m², 95% CI -0.10 to 1.82, p = 0.08), with a directional but non-significant signal observed only for the ARFS vegetable domain. These robust, well-powered null findings are reassuring rather than inconclusive they align closely with a concurrent meta-analysis of 72 international studies(3) and indicate that taste-based screening is unlikely to meaningfully improve dietary risk stratification in this population. Rather than a limitation, this convergence across independent designs strengthens confidence that structural and environmental determinants, not individual taste genotype or phenotype, remain the primary levers for improving diet quality and eating behaviour in Australian adults, informing more efficient targeting of future public health nutrition strategies.
References:
1. Collins CE, Burrows TL, Rollo ME et al. (2015) Nutrients 7, 785-798.
2. Hunot C, Fildes A, Croker H et al. (2016) Appetite 105, 356-363.
3. Shareef A, Irwin C, Vincze L et al. (2026) Nutr Res 145, 48-65.
Keywords: bitter taste sensitivity; diet quality; eating behaviour; Australian adults