The relevance of chronotype and infant feeding for the link between diurnal timing of food intake and overweight or type 2 diabetes risk

新出现的证据支持了昼夜饮食模式在心脏代谢性疾病发展中的作用。我们之前的项目提供了新的证据，特别是在晚上习惯摄入较高的血糖指数(GI)碳水化合物可能会对青年时期的2型糖尿病风险标记物产生不利影响。此外，横截面证据表明，较晚的时型在一天中较晚的时间有较高的能量摄入量。因此，在青春期至成年期期间向较晚的时型转变和/或由于社会时间表而导致时型与食物摄入时间之间的错位，可能部分解释了为什么这种寿命成为慢性病发展的“关键时间窗”。从生命过程的角度来看，阐明在婴儿期就已经存在的昼夜节律饮食模式的潜在形成是至关重要的。因此，本项目的总体目标是调查从婴儿期到成年期的昼夜节律饮食模式和/或时型与代谢健康的相关性。具体地说，我们的项目解决了能量和碳水化合物摄入的时间与个人昼夜节律之间的错位是否会对新陈代谢健康产生不利的短期和长期后果，以及婴儿时期的母乳或奶瓶喂养是否与晚年的昼夜饮食模式和身体组成有关。为了解决这些问题，我们将进行一项短期受控营养试验，并对开放队列Donald研究的数据进行二次分析。交叉试验将在每20名大学生(非肥胖，18-25岁)中进行，他们的年龄类型分为早、晚两组。使用连续血糖监测，将测试2小时血糖水平和每日血糖水平以及血糖变异性是否因早餐(即较晚时型之间的错位)或晚餐(即较早时型之间的错位)提供富含较高GI碳水化合物的同一餐而不同。此外，该项目利用了从唐纳德研究的婴儿、儿童和青少年那里前瞻性收集的数据。定期评估包括带有白天特定饮食数据和人体测量数据的3天加权饮食记录，以及关于个人年型的问卷。此外，空腹血液样本是在年轻成人时提取的，可以调查2型糖尿病风险因素的预期相关性。该项目将首次提供关于昼夜饮食模式和代谢健康之间短期和长期联系的详细信息，说明时型和婴儿喂养的相关性。这样，该项目将为社会时差风险很大的年龄组的饮食建议提供必要的证据。

Emerging evidence underpins a role of circadian eating pattern for the development of cardiometabolic diseases. Our previous project provides new evidence that particularly the habitual consumption of higher glycaemic index (GI) carbohydrate intakes in the evening may have adverse consequences for type 2 diabetes risk markers in young adulthood. Additionally, cross-sectional evidence indicates that later chronotypes have higher energy intakes at later times of the day. Hence the shift towards a later chronotype during adolescence until young adulthood and/or a misalignment between chronotype and timing of food intake due to social schedules may partially explain why this life-span emerges as a “critical time window” for the development of chronic diseases. From a life-course perspective it is crucial to also elucidate the potential shaping of circadian eating patterns already during infancy.Therefore, the overall aim of this project is to investigate the relevance of circadian eating pattern and/or chronotype for metabolic health from infancy to young adulthood. Specifically, our project addresses whether a misalignment between the timing of energy and carbohydrate intake and individual circadian rhythm as captured by chronotype has adverse short- and long-term consequences for metabolic health and whether breast- or bottle-feeding in infancy is relevant for circadian eating pattern and body composition later in life.To address these questions a short-term controlled nutrition trial and secondary analyses of data from the open-cohort DONALD study will be conducted. The cross-over trial will be performed enrolling each 20 university students (non-obese, 18-25 years) with an earlier and a later chronotype. Using continuous glucose monitoring it will be tested whether the 2-h and diurnal blood glucose levels and glycaemic variability differ in response to days where the same meal rich in higher GI carbohydrates is provided at breakfast (i.e. misalignment among later chronotypes) or dinner(i.e. misalignment among earlier chronotypes). Moreover, the project takes advantage of prospectively collected data from infants, children and adolescents of the DONALD study. Regular assessments include 3-day weighed dietary records with daytime-specific dietary data and anthropometric measurements, as well as a questionnaire on the individual chronotype. Additionally, fasting blood samples are drawn in young adulthood that allow investigating the prospective relevance for type 2 diabetes risk factors.The project will be the first to provide detailed information on the relevance of chronotype and infant feeding for the link between circadian eating pattern and metabolic health both over the short- and long-term. This way the project will contribute evidence needed for dietary recommendations in age groups at substantial risk for social jetlag.