Shinkawa Yuya, Yasuda Midori, Nishida Yuichiro, Tokiya Mikiko, Takagi Yusuke, Matsumoto Akiko, Kawaguchi Atsushi, Hara Megumi
Department of Medical Science, Graduate School of Medical Science, Saga University, Saga 849-8501, Japan.
Department of Health and Nutrition Sciences, Nishikyushu University, Saga 842-8585, Japan.
Nutrients. 2025 Jul 13;17(14):2308. doi: 10.3390/nu17142308.
: Postprandial hyperglycemia is a risk factor for diabetes and cardiovascular diseases, even in healthy individuals. Kanzaki mulberry leaf and water chestnut tea (MW tea), a blend of mulberry () leaves and water chestnut () leaves and husks, is rich in polyphenols and 1-deoxynojirimycin (DNJ) and may suppress postprandial glucose spikes, but evidence regarding its short-term daily intake is limited. This study aimed to evaluate the postprandial glycemic response and safety of two-week MW tea consumption using continuous glucose monitoring (CGM). : We conducted a randomized, double-blind, placebo-controlled, two-period crossover trial involving 31 participants. Each intervention period lasted two weeks, separated by a one-week washout. Participants consumed either MW tea or a placebo before meals. Interstitial glucose levels were measured every 15 min using CGM. Postprandial glucose responses were recorded every 15 min for 180 min after a standardized meal on the first day of each period. The primary outcome was the coefficient of variation (CV) in glucose levels, calculated using data from the central 10 days of each intervention period. Safety was assessed using CGM-derived hypoglycemia metrics and blood test results. : The CV of glucose levels during the MW tea period was significantly lower than during the placebo period (mean difference: 0.02, = 0.0006). A significant reduction in 1 h postprandial glucose area under the curve was also observed. No significant differences were found in hypoglycemia occurrence, liver/renal/inflammatory markers, or self-reported adverse symptoms. Notably, 1,5-anhydroglucitol (1,5-AG) levels significantly increased during MW tea intake, suggesting improved glycemic control. : Short-term consumption of Kanzaki MW tea effectively suppressed postprandial glucose variability without safety concerns. These findings support MW tea as a promising natural supplement for glycemic management and the prevention of diabetes.
餐后高血糖是糖尿病和心血管疾病的一个危险因素，即使在健康个体中也是如此。神崎桑叶菱角茶（MW茶）是桑叶和菱角叶及菱角壳的混合物，富含多酚和1-脱氧野尻霉素（DNJ），可能会抑制餐后血糖峰值，但关于其短期每日摄入量的证据有限。本研究旨在使用连续血糖监测（CGM）评估饮用两周MW茶后的餐后血糖反应和安全性。
我们进行了一项随机、双盲、安慰剂对照、两阶段交叉试验，纳入了31名参与者。每个干预期持续两周，中间有一周的洗脱期。参与者在饭前饮用MW茶或安慰剂。使用CGM每15分钟测量一次组织间葡萄糖水平。在每个阶段的第一天，标准化餐后180分钟内每15分钟记录一次餐后血糖反应。主要结局是使用每个干预期中间10天的数据计算的血糖水平变异系数（CV）。使用CGM得出的低血糖指标和血液检测结果评估安全性。
MW茶期的血糖水平CV显著低于安慰剂期（平均差异：0.02，P = 0.0006）。还观察到餐后1小时血糖曲线下面积显著降低。在低血糖发生率、肝/肾/炎症标志物或自我报告的不良症状方面未发现显著差异。值得注意的是，饮用MW茶期间1,5-脱水葡萄糖醇（1,5-AG）水平显著升高，表明血糖控制得到改善。
短期饮用神崎MW茶可有效抑制餐后血糖变异性，且无安全问题。这些发现支持MW茶作为一种有前景的天然补充剂用于血糖管理和糖尿病预防。
