Oral Health and Nutritional Intake in Community-Dwelling 90-Year-Old Japanese People: A Cross-Sectional Study

This study aimed to determine the relationship between dentition, mastication, salivation and nutritional intake in 90-year-old Japanese people.

This cross-sectional study included 84 participants (39 men and 45 women) aged 90 years. We used questionnaires to collect demographic information, smoking status, nutritional intake and higher-level functional capacity. Nutritional intake was assessed using the validated Brief-Type Self-Administered Diet History Questionnaire, and higher-level functional capacity was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) questionnaire. Oral examinations, masticatory performance tests, stimulated salivary flow rate (SSF) tests, blood tests, blood pressure tests and body mass index (BMI) assessments were conducted. Univariable and multivariable linear regression analyses were performed.

Multivariable linear regression analyses adjusted for sex, education, TMIG-IC and BMI ≤20 kg/m² showed that participants with masticatory performance <173 mg/dL had lower intake of folic acid and vitamin A than those with masticatory performance ≥173 mg/dL. SSF was positively associated with intake of vitamin A. The number of teeth was positively associated with the intake of β-carotene. With smaller effect sizes, masticatory performance, SSF and number of teeth were also associated with the intake of various micronutrients and carbohydrates.

Lower masticatory performance, lower SSF and fewer teeth were associated with a lower intake of several micronutrients, such as vitamin A, β-carotene and folic acids, in Japanese individuals of advanced age. Oral health practitioners should pay careful attention to the nutritional intake of older people with poor mastication, dry mouth and severe tooth loss.