Reduced Dietary Protein, Performance and Health
试验速览
- 阶段
- 不适用
- 状态
- 进行中（未招募）
- 入组人数
- 20
- 试验地点
- 2
- 主要终点
- Microbiome
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 20 Years 至 50 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Endurance athlete
- •Exercising at least 10hrs per week
- •Habitual dietary protein intake ~2g/kg body mass
排除标准
- •Food allergies that exclude the controlled diet
- •Inconsistent endurance training load
结局指标
主要结局
Microbiome
时间窗: Run-in (week-3 to week0) vs dietary intervention (week0 to week6)
Diversity of bacterial strains in gut microbiome measured in feces samples
Endurance performance on a bike
时间窗: From Pre (week0) to post (week6)
Endurance performance defined as maximal aerobic power (Wmax) during incremental test to exhaustion on a bike measured as 1-minute mean power output (W)
次要结局
- Total fat mass(Run-in (week-3) to Pre (week0))
- Training load(Run-in (week-3) vs dietary intervention (week0 to week6))
- Resting metabolic rate(Pre (week0) to Post (week6))
- Lean body mass(Pre (week0) to Post (week6))
- Fractional utilisation of maximal oxygen uptake at 4mmol/L blood lactate(Pre (week0) to Post (week6))
- Gross work efficiency on a bike(Pre (week0) to Post (week6))
- Respiratory exchange ratio(Pre (week0) to Mid (week3))
- Energy intake(Run-in (week-3) vs dietary intervention (week0 to week6))
- Power output at 4mmol/L blood lactate(Pre (week0) to Post (week6))
- Peak power output on a 10-seconds sprint(Pre (week0) to Post (week6))
- Mean power output on a 10-seconds sprint(Pre (week0) to Post (week6))
- Gross efficiency on a bike(Pre (week0) to mid (week3))
- 15-minute time-trial power output on a bike(Pre (week0) to Post (week6))
- Fractional utilisation of maximal oxygen uptake during 15-minute time-trial(Pre (week0) to Post (week6))
- Blood lactate concentration(Run-in (week-3 to week0) vs dietary intervention (week0 to week6))
- Plasma metabolomics(Run-in (week-3 to week0) vs dietary intervention (week0 to week6))
- Skeletal muscle protein expression(Pre (week0) to Post (week6))
- Maximal oxygen uptake VO2peak(Pre (week0) to Post (week6))
- Energy expenditure(Run-in (week-3) vs dietary intervention (week0 to week6))
- Blood glucose concentration(Run-in (week-3 to week0) vs dietary intervention (week0 to week6))
- Haemoglobin mass expressed in grams(Pre (week0) to Post (week6))
- Blood amino acid concentration(Run-in (week-3 to week0) vs dietary intervention (week0 to week6))
- Blood volume in ml(Pre (week0) to Mid (week3))
- Energy expenditure measured as energy intake to maintain body weight(Run-in (week-3 to week0) vs dietary intervention (week0 to week6))
研究者
Bente Kiens
Professor of Exercise, Nutrition and Metabolism, D Sci, PhD, Principal Investigator
University of Copenhagen