Yamanaka Yujiro
Laboratory of Life & Health Sciences, Faculty of Education and Graduate School of Education, Hokkaido University.
Research and Education Center for Brain Science, Hokkaido University.
Nihon Yakurigaku Zasshi. 2023;158(2):165-168. doi: 10.1254/fpj.22105.
Postprandial glucose concentration is dependent on the time of day and its concentration in the morning is lower than in the evening. The circadian rhythm of glucose metabolism is regulated by the central circadian pacemaker in the suprachiasmatic nucleus (SCN). Both the SCN circadian clock and the pancreatic clock play important role in generating and maintaining the circadian rhythm of glucose metabolism. Also, short sleep duration and circadian misalignment are closely associated with a decrease in insulin sensitivity and an increase in type2 diabetes. Increased frequency of mastication and/or thorough chewing has been reported to alter the secretion of hormones related to appetite and energy metabolism. Furthermore, we have reported that the effect of mastication on postprandial glucose metabolism is dependent on the time of day and frequency of mastication. Morning mastication but not evening decreases postprandial blood glucose concentrations and increases insulin secretion at 30 min and so-called the insulinogenic index as a marker of early-phase β-cell function. This novel finding may aid in reducing the incidence of obesity and type 2 diabetes mellitus. This review covers the basic concept of the mammalian human circadian system, the underlying mechanism causing phase adjustment of the circadian rhythms in the SCN and peripheral organs, and the effect of eating behavior (e.g., chewing frequency) on the circadian rhythm of glucose metabolism.
餐后血糖浓度取决于一天中的时间，其早晨浓度低于晚上。葡萄糖代谢的昼夜节律由视交叉上核（SCN）中的中枢昼夜节律起搏器调节。SCN昼夜节律时钟和胰腺时钟在产生和维持葡萄糖代谢的昼夜节律中都起着重要作用。此外，短睡眠时间和昼夜节律失调与胰岛素敏感性降低和2型糖尿病增加密切相关。据报道，咀嚼频率增加和/或充分咀嚼会改变与食欲和能量代谢相关的激素分泌。此外，我们已经报道咀嚼对餐后葡萄糖代谢的影响取决于一天中的时间和咀嚼频率。早晨咀嚼而非晚上咀嚼可降低餐后血糖浓度，并在30分钟时增加胰岛素分泌以及作为早期β细胞功能标志物的所谓胰岛素生成指数。这一新发现可能有助于降低肥胖症和2型糖尿病的发病率。本综述涵盖了哺乳动物昼夜节律系统的基本概念、导致SCN和外周器官昼夜节律相位调整的潜在机制，以及进食行为（如咀嚼频率）对葡萄糖代谢昼夜节律的影响。
