The goal of this clinical trial is to learn about the effect of time-restricted eating (TRE) to 10 hours per day on glucose homeostasis, markers of the circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress status in night shift workers. The main questions it aims to answer are: 1) How does a time-restricted eating protocol affect glucose homeostasis in shift workers? and 2) How does a time-restricted eating protocol affect markers of the circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress status in shift workers? Participants will be asked to follow a TRE protocol on which they must restrict their eating to a self-selected time window of 10 hours a day, with mandatory fasting time between 24:00-06:00h. for 8 weeks. Researchers will compare the intervention with an additional period of 8 weeks, in which the participants will follow their usual diet without any time restriction, to see if the intervention improves glucose regulation appetite and markers of circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress.
This is a randomized, crossover, controlled, within-subject study. After recruitment, participants will be randomized to one of two conditions: i) Time-restricted eating (TRE), with an eating window of 10 hours per day but without any other diet modification (e.g., types of food or amount of energy consumed). Each participant can freely choose the starting time of their eating window. If a participant need to make modifications to the start time of their eating window, he/she may do so only once during the TRE period, and the research team must be informed. After a washout period of at least 30 days, participants will undergo ii) Regular eating (REG), during which the participants must maintain their usual eating pattern (i.e., usual eating window), without making any dietary or lifestyle changes. Each condition will have a duration of 8 weeks. Randomization will be done using computer-generated random numbers.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
22
During the intervention (TRE) each participant will freely choose the starting time of their eating window. If needed, participant can modify the selected start time of their eating window only once during the intervention period, and the research team must be informed. After a washout period of at least 30 days, participants will undergo the opposite condition (TRE or Regular eating) after the initial randomization
Faculty of Medicine, University of Chile
Santiago, Metropolitan Region, Chile
Change from Baseline in the mean fasting glycemia at 8 weeks
Fasting glycemia level (in mg/dL) will be measured from fasting blood samples and measured with the hexokinase method
Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)
Change from baseline to end of treatment (8weeks) in 24-h glycemic control
24-h glycemic control (expressed in mg/dL), measured with continuous glucose monitoring (CGM) using a portable capillary glucose sensor, over 10 consecutive days.
Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)
24-hour motor activity level (counts/min)
Motor activity will be assessed by accelerometric recordings (actigraphic data) of wrist activity. Actigraphy data will assess motor activity before and after the intervention
Time frame: From enrollment to the end of treatment (at 8 weeks), in each study period (TRE and REG)
Change from Baseline in the circadian clock-genes expression at 8 weeks
Clock-gene expression will be evaluated by relative expression, performing RT-stem loop real-time PCR, from fasting whole-blood samples taken at baseline and after 8 weeks, in each study period. Gene expression levels of the target sequences will be normalized to the expression of GAPDH, and will be calculated by applying equation 2-∆∆ CT.
Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)
Change from baseline in thiobarbituric acid reactive substances (TBARS) level at 8 weeks
TBARS level (in µM/ml) will be measured in plasma samples
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)]
Change from baseline in F-8 isoprostane level at 8 weeks
F-8 isoprostane level (in pg/mL) will be measured in plasma samples
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)
Change from Baseline in Appetite-related feelings at 8 weeks
A visual analog scale will be used to assess appetite feeling levels. Each participant rates their subjective feelings of appetite, satiety, and desire to eat using a 100 mm visual analog scale, with endpoints indicating from "not at all" (0 mm) to "extremely" (100 mm).
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)
Change from baseline in total-, reduced- and oxidized glutathione levels at 8 weeks
Total-, reduced-, and oxidized glutathione levels (in µM) will be measured in plasma samples
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)
Change from baseline in C-reactive protein levels at 8 weeks
C-reactive protein levels (in mg/L) will be measured in serum samples
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)
Change from baseline in pro-inflammatory cytokine levels at 8 weeks
Interleukin 1β, Interleukin 6, and Tumor necrosis factor (TNF-α) levels (in pg/mL) will be measured in plasma samples.
Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)
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