epigenomic approach to understand of morningness and eveningness

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K19740
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 59:Sports sciences, physical education, health sciences, and related fields
• Research Institution: Waseda University
• Principal Investigator: SHIBATA SHIGENOBU 早稲田大学, 理工学術院, 教授 (10162629)
• Co-Investigator(Kenkyū-buntansha): 田原 優 広島大学, 医系科学研究科, 准教授 (80707399)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 体内時計 / 夜型 / カフェイン飲料 / 夜食

Outline of Final Research Achievements

Human can be categorized as morning preferred, intermediate preferred and evening preferred person by chronotype. Chronotype is determined by genetic and environmental factors. (1) We found that caffein is known to lengthen the circadian activity rhythm in mice. This lengthen effect was maintained under lesion of the suprachiasmatic (SCN) main clock, suggesting caffeine-induced SCN-independent oscillation. Thus, this newly established center may play an important role in diurnal behavior. (2) Approximately 30-40 % of 3-8 years old children takes night snacks (sweetened soft drink and ice cream). Evening preferred children frequently take night snack compared with morning preferred children. Frequency of night snack was positively related with that of smart phone use at night. These results strongly suggest that light exposure at nighttime causes night prefer children,and resulted in night snacking habits. This unhealthy snacking habit may epigenetically affect throughout life stage.

Free Research Field

時間栄養学

Academic Significance and Societal Importance of the Research Achievements

本研究から、カフェイン飲料の摂取条件を誤ると、体内時計に異常をもたらし、夜型化を助長させる可能性に注意すべきであることが分かった。このことをヒトの社会生活で考えると、カフェイン飲料の大量摂取や長期間摂取は体内時計に悪影響を及ぼす可能性が示唆された。また幼児期からの夜食習慣は、エピジェネティクな影響を通して、夜型化の固定の危険性を指摘できた。保育形態では、幼稚園に比較して保育園群は液晶画面を夜遅く使用することで夜型化が進み、夜食を摂るチャンスも増える可能性が示唆され、保育園では夜食摂取をより注意する必要がある。