Impact of Dietary Phosphate Excess on Exercise Capacity and Visceral Adiposity
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-80
SponsorUniversity of Texas Southwestern Medical Center
About this trial
Studies in mice demonstrated that dietary phosphate (Pi) loading that mimic the level of US adult consumption leads to reduced spontaneous locomotor activity, exercise capacity, and reduced resting metabolic rate when in normal mice by impairing skeletal muscle mitochondrial function and fat oxidation. However, relevance of this findings in humans remains unknown.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
None
Disqualifiers
history of cardiopulmonary disease or chronic kidney disease,
treatment with antihypertensive medications,
estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m2, (4) diabetes mellitus or other systemic illness,
Trial design
Design model
Crossover
Treatments tested in this trial
Sodium Phosphate
Dietary supplementSodium Phosphate 2 capsules daily (containing a total of 500 mg of Pi, 372mg of sodium)
Sodium Chloride
Dietary supplementSodium Chloride 2 capsules daily (NaCl, containing a total of 372mg of sodium)
Treatment groups
124 Participants
are divided into 2 treatment groupsGroup A: Sodium Phosphate (NaPO4) then sodium chloride (NaCl)Experimental treatment 2 interventions
Group B: NaCl then NaPO4Experimental treatment 2 interventions
Trial outcomes
Primary outcomes
1
oxygen uptake (VO2) during peak exercise
VO2 (ml of oxygen consumed /min) will be measured using a metabolic cart (Medgraphics) during exercise in a stationary bicycle. Standard breath-by-breath respiratory gases (VO2) will be measured at rest and after 3 minutes of steady state exercise at both 20 and 40 Watts using a cycle ergometer (Lode). Then, the partcipants will be asked to perform exercise to maximal level to obtain peak VO2.
Time frame
4 weeksSecondary outcomes
1
Resting ATP synthesis
Resting ATP synthesis (mM/min) will be measured using a magnetic resonance spectroscopy (MRS). The rate of exchange of high energy phosphates between phosphocreatine and ATP will be used to calculate resting ATP synthesis.
Time frame
4 weeks2
Phosphocreatine (PCr) depletion
PCr depletion (%) will be measured in the calf muscle after measurements of resting ATP synthesis by MRS. Participants will be asked to perform plantar flexion exercise for 1 min of foot-pushing against a magnet-compatible pulley system mounted on the scanner table constant workload (20% of estimated lean body weight at 2 s/cycle, 1 second of contraction/1 second of relaxation). Two bouts of exercise are performed by each subject with 10 min recovery between each bout and the results are averaged.
Time frame
4 weeks3
submaximal VO2
VO2 (ml of oxygen consumed /min) will be measured using a metabolic cart (Medgraphics) during exercise in a stationary bicycle. Standard breath-by-breath respiratory gases (VO2) will be measured at rest and after 3 minutes of steady state exercise at both 20 and 40 Watts using a cycle ergometer (Lode) to obtain levels of sub maximal oxygen uptake
Time frame
4 weeks4
Cardiac output (CO)
CO (ml/min) will be measured at rest and during the same stationary bicycle exercise while VO2 is monitored, using an inert gas rebreathing method. The Innocor rebreathing system (Innovision A/S, Odense, Denmark) uses a combination of both an inert soluble gas (0.5% nitrous oxide) and an inert insoluble gas (0.1% sulfur hexafluoride) and has been shown to provide a reliable assessment of lung volumes and cardiac output non-invasively.
Time frame
4 weeksSponsors and contacts
Click on the lead sponsor to view all of their trials.
Source ClinicalTrials.gov