Minoru Kouzuki1, Junya Ichikawa2, Daiki Shirasagi2, Fumiya Katsube2, Yuuki Kobashi2, Hideki Matsumoto3, Huichia Chao3, Shintaro Yoshida3, Katsuya Urakami2. 1. Department of Biological Regulation, School of Health Science, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, 683-8503, Japan. kouzuki@tottori-u.ac.jp. 2. Department of Biological Regulation, School of Health Science, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, 683-8503, Japan. 3. Research Institute for Bioscience & Fine Chemicals, Ajinomoto Co., Inc., 1-1, Suzuki-Cho, Kawasaki-Ku, Kawasaki-Shi, 210-8681, Japan.
Abstract
BACKGROUND: Patients with Alzheimer's disease dementia (ADD) are thought to exhibit taste disorders; however, this has not been extensively studied. We investigated gustatory functions and factors affecting taste in patients with ADD or mild cognitive impairment (MCI) and in non-demented controls (NDCs) and evaluated associations between cognitive impairment and gustatory functions. METHODS: We recruited 29 patients with ADD, 43 with MCI, and 14 with NDCs. We obtained medical and medication history, measured salivary secretion volumes, and performed cognitive function tests, blood tests, whole-mouth gustatory tests, and dietary and gustatory questionnaires. RESULTS: Patients with ADD showed significantly higher recognition threshold values than NDCs (p < 0.05). Many individuals did not recognize umami at the maximum concentration, and this happened more frequently in patients with ADD or MCI than in NDCs. Evaluation items other than cognitive function tests did not show significant differences among the groups, but many individuals had decreased salivation, low serum zinc levels, and were on multiple medications. We found a significant correlation between recognition threshold and age (r = 0.229, p < 0.05) and cognitive function test score (r = 0.268, p < 0.05). CONCLUSIONS: Patients with ADD showed impairment of gustatory function. Gustatory impairment in patients with MCI could not be confirmed. However, many individuals with MCI did not recognize umami, either. Our results suggest that taste disorders in elderly people with cognitive decline occur independently of factors affecting taste such as salivation, zinc levels, or prescription drugs. TRIAL REGISTRATION: The study was registered in the UMIN Clinical Trials Registry on February 10, 2017, with reference number UMIN000026087.
BACKGROUND:Patients with Alzheimer's disease dementia (ADD) are thought to exhibit taste disorders; however, this has not been extensively studied. We investigated gustatory functions and factors affecting taste in patients with ADD or mild cognitive impairment (MCI) and in non-demented controls (NDCs) and evaluated associations between cognitive impairment and gustatory functions. METHODS: We recruited 29 patients with ADD, 43 with MCI, and 14 with NDCs. We obtained medical and medication history, measured salivary secretion volumes, and performed cognitive function tests, blood tests, whole-mouth gustatory tests, and dietary and gustatory questionnaires. RESULTS:Patients with ADD showed significantly higher recognition threshold values than NDCs (p < 0.05). Many individuals did not recognize umami at the maximum concentration, and this happened more frequently in patients with ADD or MCI than in NDCs. Evaluation items other than cognitive function tests did not show significant differences among the groups, but many individuals had decreased salivation, low serum zinc levels, and were on multiple medications. We found a significant correlation between recognition threshold and age (r = 0.229, p < 0.05) and cognitive function test score (r = 0.268, p < 0.05). CONCLUSIONS:Patients with ADD showed impairment of gustatory function. Gustatory impairment in patients with MCI could not be confirmed. However, many individuals with MCI did not recognize umami, either. Our results suggest that taste disorders in elderly people with cognitive decline occur independently of factors affecting taste such as salivation, zinc levels, or prescription drugs. TRIAL REGISTRATION: The study was registered in the UMIN Clinical Trials Registry on February 10, 2017, with reference number UMIN000026087.
Authors: Celeste Ferraris; Alexandria Turner; Christopher Scarlett; Martin Veysey; Mark Lucock; Tamara Bucher; Emma L Beckett Journal: Nutrients Date: 2021-02-24 Impact factor: 5.717