Decreased Tongue-Lip Motor Function in Japanese Population with Low Taste Sensitivity: A Cross-Sectional Study

Background/Objectives: Taste disorders have a negative impact on meal enjoyment, which is essential for maintaining adequate nutrition and quality of life. Japan is a rapidly aging society with an increasing number of individuals with taste disorders. However, despite the increasing prevalence of taste disorders, the correlation between oral frailty and taste sensitivity remains largely unknown. The objective of this study was to assess the relationship between oral health status and taste sensitivity among the Japanese population. Methods: Participants were recruited from Kanagawa Dental University Hospital Medical-Dental Collaboration Center between 2018 and 2021. The exclusion criteria were severe systemic infections, pregnancy, or lactation. Clinical examinations, oral function assessments, and taste tests were conducted using tap water and 1% sweet, 0.3% salty, 0.03% umami, and 0.1% umami tastants. The relationships between oral function, systemic indicators, and taste sensitivity were statistically evaluated. Results: Of the 169 participants included in this cross-sectional study, 39.6% were male and 60.4% were female (median age, 68 years). Participants with low taste sensitivity showed a decline in tongue-lip motor function, independent of age, sex, or smoking status. A multiple logistic regression analysis conducted using two age categories-younger than 65 years and older than 65 years-revealed an association between tongue-lip motor function and taste sensitivity among participants younger than 65 years. Conclusions: Decreased taste sensitivity is associated with tongue-lip motor function. Therefore, the early maintenance of oral function and taste sensitivity may be beneficial for optimal tongue-lip motor function.