The aim of this randomized, observer-blind, controlled intervention study with parallel groups is to study the effect of resistance training (2x/week for 8 weeks) with and without different goals of protein intake on muscle strength, function and mass, oxidative stress parameters and the immune system in community dwelling persons. Participants (n = 137) will be community-dwelling older adults. After a pre-participation screening participants will be distributed randomly but stratified by sex and age to one of the 3 groups (low protein + strength training, high protein + strength training, low protein and no strength training(=control)). Study participants are eligible if they are male or female with an age between 65 and 85 years and if their cognitive status as well as their physical fitness level allows to participate at the strength training sessions. Exclusion criteria comprise chronic diseases which contraindicate the training sessions, serious cardiovascular disease, diabetic retinopathy and manifest osteoporosis, a frailty index at or above 3, medication with anticoagulants or cortisone drugs and also regular strength training during the last six months. Primary outcome measure is the change in the Chair Stand Test. Secondary outcome measures comprise anthropometric data, functional performance tests, immunological and oxidative stress parameters, microbiota, metabolomics, proteomics and the nutritional status.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
137
6 weeks of high protein intake mainly via food (additional 1g/kg bw/d) followed by a 8 weeks resistance training (Progressive strength training in a fitness center is applied; the intensity is adjusted continuously in order to obtain a sufficient training stimulus). During the training period the protein intake remains.
No Intervention, control
6 weeks of low protein intake (1g/kg bw/d) followed by a 8 weeks resistance training (Progressive strength training in a fitness center is applied; the intensity is adjusted continuously in order to obtain a sufficient training stimulus). During the training period the protein intake remains
6 weeks of different protein intake followed by a 8 weeks resistance training (Progressive strength training in a fitness center is applied; the intensity is adjusted continuously in order to obtain a sufficient training stimulus). During the training period the protein intake remains
University of Vienna, Department of Nutritional Sciences
Vienna, Austria
Change from baseline in chair stand test (repetitions)
The maximum number of completed cycles of unsupported chair rises (from a seated to a fully erected position (hip and knees straightened)) completed within 30 s is counted.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in isometric quadriceps peak torque (Nm/kg)
Isokinetic peak torque measurements of knee extensors and flexors will be performed using a LIDO Multijoint II isokinetic loading dynamometer. Participants will be tested in a sitting posion with their hip flexed at approximately 90° and subjects securely strapped to the seat of the chair using adjustable trunk and waist stabilisation belts. The anatomic axis of the knee rotation at the knee joint will aligned with the machine axis of rotation to insure similar movements for all participants. Two continuous maximal repetitions of knee extensors and knee flexors will be performed concentrically at each angular velocity (60°/s and 120°/s) for peak torque recording.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in handgrip strength (kg)
Handgrip strength of the right hand will be measured to the nearest kilogram (kg) using a hand Dynamometer. Participants will be encouraged to perform a maximal contraction within approximately 4 to 5 s. After a rest of 60 s, participants will be asked to perform a second trial. The highest score of maximum voluntary contraction will be used for data analyses.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in muscle mass with BIA (kg)
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in 6min walking test (distance in meter)
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in the composition of gut-microbiota
Gene sequencing of the 16S rRNA on the stool samples are performed to identify the microbes down to genus level, as well as the microbrobiota diversity and relative abundance.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in stool short-chain fatty acids (SCFAs)
The stool short-chain fatty acids (SCFAs) will be extracted and quantitatively analysed by gas chromatography.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in oxidative stress marker such as malondialdehyd
The investigators will consider changes in plasma concentrations of oxidative stress marker such as malondialdehyde from baseline to the end of the intervention.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in inflammatory marker (i.g. IL-6, TNF-alpha)
The investigators will consider changes in plasma concentrations of Interleukin 1 (IL-1), IL-6, IL-8, IL-10, TNF-alpha
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in the metabolomics response
The metabolomic response (ie all metabolites) to the interventions will be analyzed using both nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques. Patterns of metabolites will be evaluated with statistical techniques, ie discriminant analysis and principal component analysis.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
Change from baseline in the amino acid pattern
The plasma amino acid pattern will be assessed with HPLC-MS.
Time frame: baseline, after dietary intervention (6 weeks) and after dietary and strength training (14 weeks)
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