Effects of an Evening PROtein PrEload on Metabolic Health in Night ShIfT Workers (PROPENSITy)

Not Applicable

Recruiting

• Conditions: Shift-work Disorder; Type 2 Diabetes
• Interventions: Dietary Supplement: Placebo; Dietary Supplement: whey protein

• Registration Number: NCT04869098
• Lead Sponsor: University of Adelaide

Brief Summary

This study will compare the effects of a whey protein supplement or a placebo consumed before the evening meal on health outcomes in night shift workers.

Detailed Description

Participants are assigned in random order to two conditions, for 12 days each. The interventions are 1) a 30g whey protein preload consumed 1-1.5 hr prior to their main evening meal every day for 12 days. No other advice will be given. 2) an identical mixed-nutrient drink matched for caloric content, taste and palatability consumed 1-1.5 hr prior to their main evening meal every day for 12 days(placebo). Conditions are separated by a 2-week washout period, during which participants will be encouraged to maintain their habitual diet and physical activity levels. Metabolic testing will be performed at baseline, and at the end of both conditions.

Study Timeline

• Study First Submitted: 2021-04-26
• Study Start: 2021-04-27
• Study First Submitted QC: 2021-04-28
• Study First Posted: 2021-05-03
• Status Verified: 2024-12
• Last Update Submitted: 2024-12-18
• Last Update Posted: 2024-12-24
• Primary Completion: 2025-07-31
• Study Completion: 2026-07-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Female
• Target Recruitment: 30

Inclusion Criteria

• Female
• Night shift workers (with a minimum of 6 months in their current shift work schedule)
• 35-65 years
• BMI 28.0-35.0 kg/m2; waist circumference > 80cm
• Weight stable in the past 6 months

Exclusion Criteria

• Those working standard day time hours only, or those who work less than three to four night shifts per fortnight on average
• Personal history and/or diagnosis of: diabetes, cancer, major psychiatric disorders, liver disease, gastro-intestinal surgery or disease (including malabsorption), eating disorders, anaemia, insomnia or cardiovascular disease, and/or any other condition deemed unstable by the study physician
• Taking medications known to alter body composition or metabolism, including (but not limited to): any medication used to lower blood glucose or antidiabetic medications (metformin, sulfonylureas, Glucagon-like peptide-1 (GLP-1) analogues [i.e. exenatide], thiazolidinediones or DPP-IV inhibitors [i.e. 'gliptins']), medications affecting weight, appetite or gut motility (i.e. diuretics, domperidone, cisapride, orlistat, phentermine, topiramate)
• Participants who are taking stable doses (i.e. > 12 months) of androgenic medications (i.e. testosterone) or SSRI's will not be excluded. Personal history/diagnosis (self-reported) of diabetes (type 1 or 2), major psychiatric disorders (schizophrenia, major depressive disorder, bipolar disorder, eating disorders), gastrointestinal disorders, haematological disorders (i.e. thalassemia, iron-deficiency anaemia) insomnia, or any other medical condition, deemed unstable by the study physician
• Pregnant, planning a pregnancy or breastfeeding
• Those who have lost or gained >5% of body weight in the last 6 months
• Those who consume four or more standard drinks on a single occasion at a 'daily or almost daily' occurrence
• current smokers of cigarettes/marijuana/e-cigarettes/vaporisers
• unable to comprehend the study protocol (i.e. due to English language or cognitive difficulties)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo condition	Placebo	Participants will consume an energy-matched mixed-nutrient placebo drink 1-1.5 hr prior to their main evening meal every day for 12 days,
Whey protein preload condition	whey protein	Participants will consume 30 g whey protein isolate powder (dissolved in water) 1-1.5 hr prior to their main evening meal every day for 12 days.

Primary Outcome Measures

Name	Time	Method
Glycaemic response	12 days (3 hours meal test)	Change in glucose (AUC) following a standard breakfast

Secondary Outcome Measures

Name	Time	Method
C-Reactive Protein (CRP)	12 days	Change in fasting CRP
Blood lipids	12 days	Changes in blood lipid profile (total cholesterol, HDL-, LDL-cholesterol and triglycerides)
Glucose variability	12 days	Change in 24-hour glucose variability (as MAGE, mean amplitude of gylcaemic excursions) assessed by continuous glucose monitoring
GIP	12 days (3 hours meal test)	Change in GIP (AUC) following a standard breakfast
PYY	12 days	Change in YY (AUC) following a standard breakfast
Adiponectin	12 days	Change in fasting adiponectin
24-hour glucose profiles	12 days	Change in 24-hour glucose profiles assessed by continuous glucose monitoring
GLP-1	12 days (3 hours meal test)	Change in GLP-1 (AUC) following a standard breakfast
Resting metabolic rate	12 days	Changes in resting metabolic rate
glucagon	12 days (3 hours meal test)	Change in glucagon (AUC) following a standard breakfast
Insulin	12 days	Change in fasting and postprandial insulin following a standard breakfast
Blood pressure	12 days	Changes in systolic blood pressure and diastolic blood pressure
respiratory quotient	12 days	Changes in respiratory quotient
Ghrelin	12 days (3 hours meal test)	Change in ghrelin (AUC) following a standard breakfast

Trial Locations

Locations (1)

University of Adelaide; 🇦🇺 Adelaide, South Australia, Australia