Objectives: Patients with type 2 diabetes (T2D) are at high risk for reduced saliva volume as well as periodontal diseases, and often have dysgeusia. This study investigated whether umami stimulation could effectively ameliorate these conditions in T2D by improving the oral environment and reducing the preference for sweet taste.
Methods: Participants were 21 patients (18 men, 3 women) with T2D who were not receiving pharmacotherapy. The mean age was 61.6 ± 12.6 years (range, 34-79), mean body mass index (BMI) was 26.9 ± 5.8 kg/m2, and mean hemoglobin A1c (HbA1c) was 6.9 ± 0.7%. After patients ingested umami substances for 3 months, we evaluated recognition thresholds for sweet taste, changes in the oral environment, and clinical indices. Measurements before and after diet therapy were compared.
Results: Thresholds for sweet taste did not change significantly (before diet therapy, 4.2 ± 1.1 vs. after diet therapy, 3.2 ±1.1), but sensitivity (perception) to sweet taste showed a tendency to become stronger. The oral environment showed increased saliva volume (2.68 ± 0.9 vs. 3.24 ± 1.7 mL), decreased salivary hemoglobin (3.02 ± 2.1 vs. 2.1 ± 1.1 μg/mL), and decreased salivary lactate dehydrogenase (156.5 ± 95.5 vs. 152.5 ± 61.5 U/L). Clinical indices showed the significant reduction of body weight (71.5 ± 13.5 vs. 70.9 ± 13.4 kg; p < 0.05) and BMI (26.9 ± 5.8 vs. 26.6 ± 5.7 kg/m2; p < 0.05). HbA1c values decreased (6.9 ± 0.7 vs. 6.8 ± 0.6%). Fasting blood glucose (139.3 ± 24.2 vs. 122.3 ± 16.8 mg/dL; p < 0.05) and tumor necrosis factor-α (0.85 ± 0.4 vs. 0.71 ± 0.3 pg/mL; p < 0.05) decreased significantly.
Conclusion: These results suggest that umami stimulation effectively alters oral environment, reduces sweet taste preference, and improves type 2 diabetic condition.
C. Sakai: None. Y. Horikoshi: None. E. Mizuta: None. T. Matsura: None. K. Hanaki: None.
Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Numbers 19K10851 (C.S.) and 22K10781 (C.S.).
