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Protein and Performance (PROPER) in Endurance Athletes (PROPER)

Primary Purpose

Diet, Healthy, Protein Deficiency

Status
Recruiting
Phase
Not Applicable
Locations
Denmark
Study Type
Interventional
Intervention
Dietary intervention of reduced protein intake
Dietary intervention of normal protein intake
Sponsored by
University of Copenhagen
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional basic science trial for Diet, Healthy focused on measuring Diet intervention, Endurance athletes, Endurance performance, Skeletal muscle protein synthesis, Protein intake, Health markers, Microbiome

Eligibility Criteria

20 Years - 50 Years (Adult)MaleAccepts Healthy Volunteers

Inclusion Criteria:

  • Endurance athlete
  • Exercising at least 10hrs per week
  • Habitual dietary protein intake ~2g/kg body mass
  • BMI<25

Exclusion Criteria:

  • Food allergies that exclude the controlled diet
  • Inconsistent endurance training load

Sites / Locations

  • University of CopenhagenRecruiting

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Active Comparator

Arm Label

Reduced protein diet

Normal protein diet

Arm Description

A 6-week eucaloric dietary intervention of reduced protein intake (~1g protein/kg body mass). The diet will, hence, contain ~7E% protein, ~63E% carbohydrate, and ~29E% fat. Participants are free-living and receive all food pre-packed from the study kitchen. The energy provision will be set to match energy balance.

A 6-week eucaloric dietary intervention of normal protein intake (~2g protein/kg body mass). The diet will, hence, contain ~16E% protein, ~53E% carbohydrate, and ~30E% fat. Participants are free-living and receive all food pre-packed from the study kitchen. The energy provision will be set to match energy balance.

Outcomes

Primary Outcome Measures

Endurance performance on a bike
Endurance performance defined as maximal aerobic power (Wmax) during incremental test to exhaustion on a bike measured as 1-minute mean power output (W)
Microbiome
Diversity of bacterial strains in gut microbiome measured in feces samples

Secondary Outcome Measures

Resting metabolic rate
Measured in an over-night fasted state via indirect calorimetry expressed in MJ/day
Resting metabolic rate
Measured in an over-night fasted state via indirect calorimetry expressed in MJ/day
Lean body mass
Measured by dual-energy x-ray (DXA)-scanningg expressed in kg
Lean body mass
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Total fat mass
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Total fat mass
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Total fat mass
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Power output at 4mmol/L blood lactate
Alterations in Power output at 4mmol/L blood lactate in response to diet
Power output at 4mmol/L blood lactate
Alterations in Power output at 4mmol/L blood lactate in response to diet
Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate
Alterations in Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate in response to diet
Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate
Alterations in Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate in response to diet
Maximal oxygen uptake VO2peak
Alterations in Maximal oxygen uptake VO2peak measured by an online VO2 apparatus
Maximal oxygen uptake VO2peak
Alterations in Maximal oxygen uptake VO2peak measured by an online VO2 apparatus
Peak power output on a 10-seconds sprint
Alterations in peak power output on a 10-seconds sprint in response to diet
Peak power output on a 10-seconds sprint
Alterations in peak power output on a 10-seconds sprint in response to diet
Mean power output on a 10-seconds sprint
Alterations in mean power output on a 10-seconds sprint in response to diet
Mean power output on a 10-seconds sprint
Alterations in mean power output on a 10-seconds sprint in response to diet
Gross efficiency on a bike
Gross efficiency expressed as % of external power compared to internal (metabolic) power
Gross work efficiency on a bike
Gross efficiency expressed as % of external power compared to internal (metabolic) power
15-minute time-trial power output on a bike
Alterations in 15-minute time-trial mean power output
15-minute time-trial power output on a bike
Alterations in 15-minute time-trial mean power output
Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Alterations in Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Alterations in Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Respiratory exchange ratio
respiratory exchange ratio (RER) during rest and exercise using indirect calorimetry
Respiratory exchange ratio
respiratory exchange ratio (RER) during rest and exercise using indirect calorimetry
Training load
Training load as quantified by Edward's Training Impulse based on heart rate zones
Energy intake
Habitual energy intake registered by food diaries expressed in Mega Joules
Energy expenditure
Energy expenditure is measured by combining resting metabolic rate and daily activity recording from accelerometer data and heart rate monitor
Blood lactate concentration
Glucose lactate measured in fasted state on an ABL800
Blood glucose concentration
Glucose concentration measured in fasted state on an ABL800
Blood amino acid concentration
Amino acid concentration measured by ELISA
Plasma metabolomics
Plasma metabolomics by chromatography-mass spectrometry
Skeletal muscle protein expression
Alterations in Skeletal muscle protein expression
Skeletal muscle protein expression
Alterations in Skeletal muscle protein expression
Haemoglobin mass expressed in grams
Haemoglobin mass measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Haemoglobin mass expressed in grams
Haemoglobin mass measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Blood volume in ml
Blood volume measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Blood volume in ml
Blood volume measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Energy expenditure measured as energy intake to maintain body weight
Daily energy intake during intervention measured in Mega Joules

Full Information

First Posted
September 22, 2021
Last Updated
November 2, 2022
Sponsor
University of Copenhagen
Collaborators
Maastricht University Medical Center
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1. Study Identification

Unique Protocol Identification Number
NCT05426447
Brief Title
Protein and Performance (PROPER) in Endurance Athletes
Acronym
PROPER
Official Title
Reduced Dietary Protein, Performance and Health
Study Type
Interventional

2. Study Status

Record Verification Date
November 2022
Overall Recruitment Status
Recruiting
Study Start Date
February 23, 2021 (Actual)
Primary Completion Date
December 31, 2024 (Anticipated)
Study Completion Date
December 31, 2025 (Anticipated)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
University of Copenhagen
Collaborators
Maastricht University Medical Center

4. Oversight

Studies a U.S. FDA-regulated Drug Product
No
Studies a U.S. FDA-regulated Device Product
No
Data Monitoring Committee
No

5. Study Description

Brief Summary
The present study is a parallel group design with randomised allocation to either a 1) reduced protein diet (RP) or a 2) normal protein diet (NP). The two groups will be pair-matched based on habitual dietary protein intake, endurance training, endurance performance, and sex. The aim of the study is to investigate the effects of reducing dietary protein (~1g protein/kg body mass) compared to an eucaloric normal protein diet (~2g protein/kg body mass) for 6 weeks in well-trained endurance athletes on endurance performance, body composition, skeletal muscle protein synthesis, and health-related outcomes. The hypothesis is that endurance performance will maintain or even be improved in well-trained endurance athletes after a 6-week dietary intervention of an eucaloric, protein reduced diet compared to a normal protein rich diet.
Detailed Description
Design: The present study will include two phases: a 3-week run-in period, and a 6-week intervention of controlled diets containing either a reduced dietary protein (RP) or normal (habitual) protein (NP). The run-in period serves as a period for obtaining general activity data and habitual dietary and training habits in order to match the groups before entering the dietary intervention period. Subjects and dietary goals: The study is aiming at including 20 male endurance athletes exercising ~15hrs+/week. The 20 males will be pair-matched based on habitual endurance training, habitual dietary protein intake, and endurance performance, and allocated in a randomised order to: 1) a reduced-protein diet (RP) or 2) a normal-protein diet (NP). 3-weeks run-in period: After a minimum of 7 days after written consent has been obtained, the run-in period will begin. Habitual endurance training volumes will be registered in an online platform (TrainingPeaks) and daily activity level will be monitored using an accelerometer (SENS) throughout the run-in and diet intervention period. "Heavy water" (D2O) will be ingested in a large bolus (3.5ml/kg LBM) upon beginning of the run-in period and plasma enrichments will be maintained throughout the study period by ingesting small daily boluses. This serves to determine skeletal muscle protein synthesis throughout the study. 6-weeks dietary intervention: The diets will be eucaloric and the estimated energy percentages for macronutrients will be as follows: RP - Protein ~7E%, Carbohydrate ~63E%, Fat ~29E%. NP - Protein ~16E%, Carbohydrate ~53E%, Fat ~30E%. Weekly urine and faeces samples will be collected during the run-in period and dietary intervention and the controlled diets will be supplied weekly for the participants. Testing: Extensive endurance performance and metabolic testing will be performed prior to-, and during the intervention on weeks -1, 0 (Pre), 3 (Mid), and 6 (Post). The tests include: Body composition by DXA-scanning, resting metabolic rate by online respirometry using a Vyntus (Jaeger, PCX), venous blood-, and skeletal muscle biopsy sampling from m. Vastus Lateralis, a standardised breakfasts, endurance cycling on an electro-magnetically braked bike (Lode Excalibur) or running on a motorised treadmill (Woodway), and haemoglobin mass measuring using a modified version of the CO-rebreathing method. The body mass will be kept unchanged during the 6-weeks dietary intervention.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Diet, Healthy, Protein Deficiency
Keywords
Diet intervention, Endurance athletes, Endurance performance, Skeletal muscle protein synthesis, Protein intake, Health markers, Microbiome

7. Study Design

Primary Purpose
Basic Science
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Model Description
A pair-matched group, parallel design within each sex
Masking
None (Open Label)
Allocation
Randomized
Enrollment
20 (Anticipated)

8. Arms, Groups, and Interventions

Arm Title
Reduced protein diet
Arm Type
Experimental
Arm Description
A 6-week eucaloric dietary intervention of reduced protein intake (~1g protein/kg body mass). The diet will, hence, contain ~7E% protein, ~63E% carbohydrate, and ~29E% fat. Participants are free-living and receive all food pre-packed from the study kitchen. The energy provision will be set to match energy balance.
Arm Title
Normal protein diet
Arm Type
Active Comparator
Arm Description
A 6-week eucaloric dietary intervention of normal protein intake (~2g protein/kg body mass). The diet will, hence, contain ~16E% protein, ~53E% carbohydrate, and ~30E% fat. Participants are free-living and receive all food pre-packed from the study kitchen. The energy provision will be set to match energy balance.
Intervention Type
Other
Intervention Name(s)
Dietary intervention of reduced protein intake
Intervention Description
6-wk dietary intervention of reduced protein intake
Intervention Type
Other
Intervention Name(s)
Dietary intervention of normal protein intake
Intervention Description
6-wk dietary intervention of normal protein intake
Primary Outcome Measure Information:
Title
Endurance performance on a bike
Description
Endurance performance defined as maximal aerobic power (Wmax) during incremental test to exhaustion on a bike measured as 1-minute mean power output (W)
Time Frame
From Pre (week0) to post (week6)
Title
Microbiome
Description
Diversity of bacterial strains in gut microbiome measured in feces samples
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Secondary Outcome Measure Information:
Title
Resting metabolic rate
Description
Measured in an over-night fasted state via indirect calorimetry expressed in MJ/day
Time Frame
Pre (week0) to mid (week3)
Title
Resting metabolic rate
Description
Measured in an over-night fasted state via indirect calorimetry expressed in MJ/day
Time Frame
Pre (week0) to Post (week6)
Title
Lean body mass
Description
Measured by dual-energy x-ray (DXA)-scanningg expressed in kg
Time Frame
Run-in (week-3) to Pre (week0)
Title
Lean body mass
Description
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Time Frame
Pre (week0) to Post (week6)
Title
Total fat mass
Description
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Time Frame
Pre (week0) to Post (week6)
Title
Total fat mass
Description
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Time Frame
Pre (week0) to mid (week3)
Title
Total fat mass
Description
Measured by dual-energy x-ray (DXA)-scanning expressed in kg
Time Frame
Run-in (week-3) to Pre (week0)
Title
Power output at 4mmol/L blood lactate
Description
Alterations in Power output at 4mmol/L blood lactate in response to diet
Time Frame
Pre (week0) to mid (week3)
Title
Power output at 4mmol/L blood lactate
Description
Alterations in Power output at 4mmol/L blood lactate in response to diet
Time Frame
Pre (week0) to Post (week6)
Title
Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate
Description
Alterations in Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate in response to diet
Time Frame
Pre (week0) to mid (week3)
Title
Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate
Description
Alterations in Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate in response to diet
Time Frame
Pre (week0) to Post (week6)
Title
Maximal oxygen uptake VO2peak
Description
Alterations in Maximal oxygen uptake VO2peak measured by an online VO2 apparatus
Time Frame
Pre (week0) to mid (week3)
Title
Maximal oxygen uptake VO2peak
Description
Alterations in Maximal oxygen uptake VO2peak measured by an online VO2 apparatus
Time Frame
Pre (week0) to Post (week6)
Title
Peak power output on a 10-seconds sprint
Description
Alterations in peak power output on a 10-seconds sprint in response to diet
Time Frame
Pre (week0) to mid (week3)
Title
Peak power output on a 10-seconds sprint
Description
Alterations in peak power output on a 10-seconds sprint in response to diet
Time Frame
Pre (week0) to Post (week6)
Title
Mean power output on a 10-seconds sprint
Description
Alterations in mean power output on a 10-seconds sprint in response to diet
Time Frame
Pre (week0) to mid (week3)
Title
Mean power output on a 10-seconds sprint
Description
Alterations in mean power output on a 10-seconds sprint in response to diet
Time Frame
Pre (week0) to Post (week6)
Title
Gross efficiency on a bike
Description
Gross efficiency expressed as % of external power compared to internal (metabolic) power
Time Frame
Pre (week0) to mid (week3)
Title
Gross work efficiency on a bike
Description
Gross efficiency expressed as % of external power compared to internal (metabolic) power
Time Frame
Pre (week0) to Post (week6)
Title
15-minute time-trial power output on a bike
Description
Alterations in 15-minute time-trial mean power output
Time Frame
Pre (week0) to mid (week3)
Title
15-minute time-trial power output on a bike
Description
Alterations in 15-minute time-trial mean power output
Time Frame
Pre (week0) to Post (week6)
Title
Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Description
Alterations in Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Time Frame
Pre (week0) to mid (week3)
Title
Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Description
Alterations in Fractional utilisation of maximal oxygen uptake during 15-minute time-trial
Time Frame
Pre (week0) to Post (week6)
Title
Respiratory exchange ratio
Description
respiratory exchange ratio (RER) during rest and exercise using indirect calorimetry
Time Frame
Pre (week0) to Post (week6)
Title
Respiratory exchange ratio
Description
respiratory exchange ratio (RER) during rest and exercise using indirect calorimetry
Time Frame
Pre (week0) to Mid (week3)
Title
Training load
Description
Training load as quantified by Edward's Training Impulse based on heart rate zones
Time Frame
Run-in (week-3) vs dietary intervention (week0 to week6)
Title
Energy intake
Description
Habitual energy intake registered by food diaries expressed in Mega Joules
Time Frame
Run-in (week-3) vs dietary intervention (week0 to week6)
Title
Energy expenditure
Description
Energy expenditure is measured by combining resting metabolic rate and daily activity recording from accelerometer data and heart rate monitor
Time Frame
Run-in (week-3) vs dietary intervention (week0 to week6)
Title
Blood lactate concentration
Description
Glucose lactate measured in fasted state on an ABL800
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Title
Blood glucose concentration
Description
Glucose concentration measured in fasted state on an ABL800
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Title
Blood amino acid concentration
Description
Amino acid concentration measured by ELISA
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Title
Plasma metabolomics
Description
Plasma metabolomics by chromatography-mass spectrometry
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Title
Skeletal muscle protein expression
Description
Alterations in Skeletal muscle protein expression
Time Frame
Pre (week0) to mid (week3)
Title
Skeletal muscle protein expression
Description
Alterations in Skeletal muscle protein expression
Time Frame
Pre (week0) to Post (week6)
Title
Haemoglobin mass expressed in grams
Description
Haemoglobin mass measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Time Frame
Pre (week0) to mid (week3)
Title
Haemoglobin mass expressed in grams
Description
Haemoglobin mass measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Time Frame
Pre (week0) to Post (week6)
Title
Blood volume in ml
Description
Blood volume measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Time Frame
Pre (week0) to Post (week6)
Title
Blood volume in ml
Description
Blood volume measured via inhalation of carbon monoxide (CO) using the modified CO-rebreathing method
Time Frame
Pre (week0) to Mid (week3)
Title
Energy expenditure measured as energy intake to maintain body weight
Description
Daily energy intake during intervention measured in Mega Joules
Time Frame
Run-in (week-3 to week0) vs dietary intervention (week0 to week6)

10. Eligibility

Sex
Male
Minimum Age & Unit of Time
20 Years
Maximum Age & Unit of Time
50 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria: Endurance athlete Exercising at least 10hrs per week Habitual dietary protein intake ~2g/kg body mass BMI<25 Exclusion Criteria: Food allergies that exclude the controlled diet Inconsistent endurance training load
Central Contact Person:
First Name & Middle Initial & Last Name or Official Title & Degree
Bente Kiens, Professor
Phone
+4535321619
Email
bkiens@nexs.ku.dk
First Name & Middle Initial & Last Name or Official Title & Degree
Andreas Fritzen, ass. Prof
Phone
+4542633359
Email
amfritzen@nexs.ku.dk
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Nicki W Almquist, Post Doc
Organizational Affiliation
University of Copenhagen
Official's Role
Study Director
First Name & Middle Initial & Last Name & Degree
Bente Kiens, Professor
Organizational Affiliation
University of Copenhagen
Official's Role
Principal Investigator
Facility Information:
Facility Name
University of Copenhagen
City
Copenhagen
ZIP/Postal Code
2100
Country
Denmark
Individual Site Status
Recruiting
Facility Contact:
First Name & Middle Initial & Last Name & Degree
Nicki W Almquist, Post Doc
Phone
+4593601842
Email
nwa@nexs.ku.dk
First Name & Middle Initial & Last Name & Degree
Andreas M Fritzen, Post Doc
Phone
+4542633359
Email
amfritzen@nexs.ku.dk

12. IPD Sharing Statement

Plan to Share IPD
No

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Protein and Performance (PROPER) in Endurance Athletes

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