Recruiting

Observational Study

Sponsor:

University of Texas Southwestern Medical Center

Code:

NCT05147909

Conditions

Physical Inactivity

Phosphate Overload

Visceral Obesity

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Interventions

Sodium Phosphate

Sodium Chloride

Study Details

Brief summary:

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.

Conditions

Physical Inactivity

Phosphate Overload

Visceral Obesity

Study ID

NCT05147909

Start date

Sep 14, 2022

Status verified date

Feb, 2026

Completion date

Mar 30, 2028

Anticipated

Primary completion date

Mar 31, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Inclusion Criteria:

The randomized crossover trial will be performed in on otherwise healthy subjects without diabetes mellitus, chronic kidney disease (CKD), preexisting cardiovascular disease or treatment with any vasoactive agent that might alter cardiovascular responses to exercise.

Exclusion Criteria:

1. history of cardiopulmonary disease or chronic kidney disease,
2. treatment with antihypertensive medications,
3. estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m2, (4) diabetes mellitus or other systemic illness,

(5) pregnancy, (6) hypersensitivity to sodium phosphate, (7) any history of substance abuse or current cigarette use, (8) any history of psychiatric illness, (9) history of active malignancy, (10) serum phosphorus < 2.4 or > 4.5 mg/dL.

Study Design

Enrollment

124 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: Sodium Phosphate (NaPO4) then sodium chloride (NaCl)

Participants will be asked to take 2 capsules daily of Sodium Phosphate (containing a total of 500 mg of Pi, 372mg of sodium) ) for 4 weeks during the high Pi phase (total Pi intake 1,200 mg/d). Then, participants will be asked to take 2 capsules of Sodium Chloride (NaCl, containing a total of 372mg of sodium) to match Na content to Sodium Phosphate without extra Pi daily for 4 weeks during the low Pi phase (total Pi intake = 700 mg/d).

experimental: NaCl then NaPO4

Participants will be asked to take 2 capsules daily of Sodium Chloride (NaCl, containing a total of 372mg of sodium) for 4 weeks during the low Pi phase (total Pi intake = 700 mg/d). Then, participants will be asked to take 2 capsules of Sodium Phosphate daily for 4 weeks Sodium Phosphate (containing a total of 500 mg of Pi, 372mg of sodium) for 4 weeks during the high Pi phase (total Pi intake 1,200 mg/d).

Interventions

Sodium Phosphate

Sodium Phosphate 2 capsules daily (containing a total of 500 mg of Pi, 372mg of sodium)

Sodium Chloride

Sodium Chloride 2 capsules daily (NaCl, containing a total of 372mg of sodium)

Primary outcome measure

  • oxygen uptake (VO2) during peak exercise [ Time Frame: 4 weeks ]

Central Contacts and Locations

Central contacts

John Giacona, PA-C

2146484403john.giacona@utsouthwestern.edu

Locations

University of Texas Southwestern

Recruiting

Dallas, Texas, United States, 75209

More Information

Sponsor

University of Texas Southwestern Medical Center

Last update posted

Feb 17, 2026

Last verified

Feb, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Texas Southwestern Medical Center on 2026-02-17.