探討第2型糖尿病患者甜味味覺及其相關之因子

Investigation of the Sweet Taste and Related Factors in Type 2 Diabetes

糖尿病患者應該有良好的飲食習慣以控制血糖，而味覺敏銳度為影響食物喜愛與選擇的重要因子。本實驗室過去的研究中發現，水果升糖指數(glycemic index; GI)值排序，與第2型糖尿病患者認知的可吃與不可吃之水果排序結果不一致，因此，若能了解糖尿病患者甜味感受度及甜味 敏銳度較差的原因，對於第2型糖尿病患者的血糖控制將有正面的幫助。故本研究的主要目的為， 比較健康受試者與第2型糖尿病患者的甜味味覺敏銳度（甜味識別閾值、果汁甜味感受度），並 探討類升糖素胜肽（Glucagon－like peptide－1; GLP－1）、胰島素（Insulin）等荷爾蒙是否為影響第2型糖尿病病患者甜味味覺的可能因子。招募10位30～65歲之第2型糖尿病患者及16位健康受試者，糖化血色素（glycosylated hemoglobin; HbA1c）分別為7～9%及 ≤ 6%。實驗分成兩大部分，第一部分為感官品評，利用甜味識別閾值測試（recognition threshold test of sweetness）及果汁甜味感 受度測試（sensory test of juice sweetness），來評估受試者的甜味味覺。第二部分為給予受試者含有25公克碳水化合物的果汁，觀察受試者飲用前後相關荷爾蒙之變化。結果顯示，糖尿病組的甜味識別閾值皆高於健康組，若以人數分佈來分析，則發現糖尿病組有顯著較差的葡萄糖敏銳度（p < 0.05），且味覺受損程度會受到HbA1c、空腹血糖值、糖尿病疾病史的影響。當以Visual Analogue Scale （VAS）量表測量果汁甜味感受度方面，兩組的芒果汁甜味感受度相近，而黃金奇異果汁的甜 味感受度，健康組為3.0 ± 0.5，糖尿病組為2.1 ± 0.4，雖然未達統計差異，但糖尿病有較低的甜味感受度，顯示其有較低的甜味敏銳度。另外，荷爾蒙變化部份，糖尿病組在飲用黃金奇異果汁後的GLP-1、Insulin單位時間分泌量皆小於健康組。綜合本研究結果顯示，血糖控制不良的第2型糖尿病組有較遲鈍的甜味味覺，尤其是有顯著較差的葡萄糖敏銳度，且糖尿病患者GLP－1、Insulin等荷爾蒙之分泌機制不同於健康者，可能為影響糖尿病患者甜味味覺之因子。

Purpose: This study was to investigate the sweet sensitivity (recognition threshold of sweetness, sensory of juice sweetness) in type 2 diabetes. We also elucidated the effect of hormone: Glucagonlike peptide-1 (GLP-1) and insulin on sweet taste. Method: The study was conducted on 26 subjects (16 healthy subjects and 10 type 2 diabetes) aged 30~65 years. The inclusion criteria were glycosylated hemoglobin (HbA1c) 7~9% for type 2 diabetes and ≦ 6% for healthy subjects. Recognition thresholds of sweetness (glucose, sucrose and fructose) and sensory of juice sweetness (golden kiwifruit, mango) were examined. After an overnight fasting, subjects consumed the juices (golden kiwifruit) containing 25 g carbohydrate and then the blood samples of subjects were taken at baseline, 15, 30, 60, 90, 120 mins to measure the concentration of GLP-1 and insulin. Results: Compared with healthy subjects, the recognition thresholds of sweetness (glucose, sucrose and fructose) were higher in type 2 diabetes. A significant difference was found in sensitivity of glucose (p < 0.05). Furthermore, HbA1c, fasting blood glucose and diabetic duration influenced the recognition thresholds of sweetness. The postprandial secretion of GLP-1 and insulin were decreased in type 2 diabetes. Conclusion: Type 2 diabetes have a blunted taste of sweetness, especially for glucose. The secretion or regulation mechanisms of GLP-1 and insulin were different between healthy subjects and type 2 diabetes. If plasma blood glucose can be controlled well, there is less impairment on the sweet taste.