Sweet treats before sleep disrupt the clock system and increase metabolic risk markers in healthy rats

Abstract

AimBiological rhythms are endogenously generated natural cycles that act as pacemakers of different physiological mechanisms and homeostasis in the organism, and whose disruption increases metabolic risk. The circadian rhythm is not only reset by light but it is also regulated by behavioral cues such as timing of food intake. This study investigates whether the chronic consumption of a sweet treat before sleeping can disrupt diurnal rhythmicity and metabolism in healthy rats.MethodsFor this, 32 Fischer rats were administered daily a low dose of sugar (160 mg/kg, equivalent to 2.5 g in humans) as a sweet treat at 8:00 a.m. or 8:00 p.m. (ZT0 and ZT12, respectively) for 4 weeks. To elucidate diurnal rhythmicity of clock gene expression and metabolic parameters, animals were sacrificed at different times, including 1, 7, 13, and 19 h after the last sugar dose (ZT1, ZT7, ZT13, and ZT19).ResultsIncreased body weight gain and higher cardiometabolic risk were observed when sweet treat was administered at the beginning of the resting period. Moreover, central clock and food intake signaling genes varied depending on snack time. Specifically, the hypothalamic expression of Nampt, Bmal1, Rev‐erbα, and Cart showed prominent changes in their diurnal expression pattern, highlighting that sweet treat before bedtime disrupts hypothalamic control of energy homeostasis.ConclusionsThese results show that central clock genes and metabolic effects following a low dose of sugar are strongly time‐dependent, causing higher circadian metabolic disruption when it is consumed at the beginning of the resting period, that is, with the late‐night snack.

Subcellular physiology

“…Interestingly, the study of circadian rhythms, a field which is by nature interdisciplinary and relevant to several preclinical and clinical specialties, has become a preferred environment for multimodal multidimensional data analysis, 6 with research projects focusing on outcomes as diverse as personalized treatment for ICU patients with circadian network disturbances, 7 targeted timed exercise interventions for diabetes management, 8 and studying the effects of hypercaloric snacking at different times in the day on hypothalamic control of energy homeostasis and thus circadian metabolic disruption by metabolomic profiling. 9 In another subspecialty, Dumont et al describe how screening, −omics, and genome-wide association studies have successfully been applied to identify the members of a diverse molecular family of proteins, PACSINs, involved in the regulation of cell cytoskeleton, intracellular trafficking and signaling, to be associated with mammalian pathophysiology. 10 Pohl et al 11 highlight the need for comprehensive characterization of cellular marker profiles to enable unbiased screening for the determination of cell identity, as exemplified on endothelial cells and their plasticity in renal disease.…”

“…Interestingly, the study of circadian rhythms, a field which is by nature interdisciplinary and relevant to several preclinical and clinical specialties, has become a preferred environment for multimodal multidimensional data analysis, 6 with research projects focusing on outcomes as diverse as personalized treatment for ICU patients with circadian network disturbances, 7 targeted timed exercise interventions for diabetes management, 8 and studying the effects of hypercaloric snacking at different times in the day on hypothalamic control of energy homeostasis and thus circadian metabolic disruption by metabolomic profiling 9 . In another subspecialty, Dumont et al.…”