Department of Nutrition, Dietetics and Food, Monash University, Melbourne, Victoria, Australia.
School of Agriculture and Food, The University of Melbourne, Melbourne, Victoria, Australia.
Clin Nutr. 2021 Jun;40(6):4349-4359. doi: 10.1016/j.clnu.2021.01.011. Epub 2021 Jan 18.
BACKGROUND & AIMS: Eating at night has been linked to impaired glucose metabolism and dyslipidaemia that is likely a consequence of an underlying disrupted circadian rhythm in metabolic processes. The aim of this study was to explore the gene expression differences after eating a standard test meal or high protein test meal at night compared with the same meal in the morning.
In a cross over design, 10 healthy adults fasted for >10 h and then completed four acute meal challenges at 8am and 8pm on non-consecutive days separated by a wash out, consuming either a high protein low carbohydrate test meal or an isocaloric standard protein and carbohydrate test meal. Fasting and two-hour postprandial blood samples were collected to measure gene expression. For a subset of five participants RNA sequencing was completed on the Illumina NextSeq500.
The time of day a meal is consumed had an effect on which genes were differentially regulated in the acute postprandial period, with only 6.5% of differentially expressed genes the same both morning and night. More genes were involved in lipid metabolic pathways in the morning and immune pathways at night. RTqPCR analysis of target genes suggested that key regulatory genes responsible for nutrient sensing and lipid and glucose metabolism are differentially expressed at night. These may play a role in improved blood glucose control in peripheral tissues that is observed after eating in the morning but to a lesser extent or not at all at night. Modulation of the macronutrient composition of a meal led to changes in expression of genes involved in the circadian clock and metabolism.
Investigating the differences in the transcriptomic response to food at night provides a greater understanding of the mechanisms underlying the changing metabolic phenotypes, characterised by circulating metabolic biomarkers, according to the time of day.
夜间进食与葡萄糖代谢受损和血脂异常有关，而这很可能是代谢过程中潜在的昼夜节律紊乱的结果。本研究旨在探索与早晨相比，夜间进食标准测试餐或高蛋白测试餐与同一餐在餐后的基因表达差异。
采用交叉设计，10 名健康成年人禁食>10 小时，然后在非连续日的 8 点和 8 点分别进行四次急性餐挑战，并在洗脱期之间进行一次高蛋白质低碳水化合物测试餐或等热量标准蛋白质和碳水化合物测试餐。采集空腹和餐后两小时的血样以测量基因表达。对于五名参与者的一部分，使用 Illumina NextSeq500 进行 RNA 测序。
进餐时间会影响餐后急性期间差异调节的基因，早晨和晚上只有 6.5%的差异表达基因相同。更多的基因参与了早晨的脂质代谢途径和夜间的免疫途径。靶基因的 RTqPCR 分析表明，负责营养感应和脂质及葡萄糖代谢的关键调节基因在夜间表达不同。这些可能在早晨进食后观察到的外周组织血糖控制改善中发挥作用，但在夜间则作用较小或不存在。宏量营养素组成的调制导致参与昼夜节律和代谢的基因表达发生变化。
研究夜间食物对转录组的反应差异，可以更深入地了解根据时间变化的代谢表型的代谢变化的潜在机制，这些表型的特征是循环代谢生物标志物。
