The relevance of chronotype and infant feeding

Our previous DFG funded project on “Modern circadian eating patterns in childhood and adolescence: Characteristics, trends, determinants and relevance for overweight and type 2 diabetes risk” showed that 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. Cross-sectional evidence indicates that later chronotypes have higher energy intakes at later times of the day. Hence, the shift towards a later chronotype which manifests during adolescence until young adulthood and/or a misalignment between chronotype and timing of food intake due to social schedules (social jetlag) 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.

These questions are addressed in a cross-over trial (1) and the open-cohort DONALD study (2).

(1) 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).

(2) Data from infants, children and adolescents regarding diet, anthropometrics and chronotype are collected in the DONALD study. Additionally, fasting blood samples are drawn in young adulthood that allows investigating the prospective relevance for type 2 diabetes risk factors.

This 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. The results will substantially contribute to the evidence required for dietary recommendations on age groups being at substantial risk for social jetlag.