The Impact of a Low or High Phosphate Diet on Phosphate and Calcium Excretion in Healthy People

Phosphate is present in many of the foods that the investigators eat and is required by many cellular processes. The kidneys are the only organ that excrete the extra phosphate from the diet that the body does not require. Phosphate is linked to vascular calcification and cardiovascular disease. Measures of serum phosphate do not reflect the burden of phosphate and are not sensitive to early changes in the way the kidneys eliminate phosphate. This study will determine whether the kidneys handle an oral phosphate load differently after 5 days of a low phosphate diet compared to 5 days of a high phosphate diet.

Study Overview

• Status: Unknown
• Conditions: Cardiovascular Diseases; Aging; Nutrient; Excess
• Intervention / Treatment: Dietary supplement: Phosphate supplemented diet

Detailed Description

In this study, participants will follow a low-phosphorus diet (750 mg) with a 500 mg calcium supplement for 5 days keeping a detailed diary of the foods eaten during this period. On the 5th day, the participant will undergo a 24 hour urine collection. Participants will present after an overnight fast for baseline blood and urine measurements. Then they will consume water containing 500 mg of phosphorus. Urine and blood will be collected every hour for 3 hours for measurement of phosphate and calcium and for measurement of hormones known to regulate phosphate and calcium including fibroblast growth factor-23, parathyroid hormone and vitamin D. One week later, participants will follow the same diet but will also receive a 1250 mg phosphorus supplement for 5 days. On the 5th day, urine will be collected for 24 hours. Participants will present again after an overnight fast and undergo the identical testing.

• Study Type: Interventional
• Enrollment (Anticipated): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Kingston, Ontario, Canada, K7L3V6
      • Recruiting
      • Queen's University
      • Contact: Corinne Babiolakis, MSc; Phone Number: 79579 613-533-6000; Email: csb8@queensu.ca
      • Contact: Rachel Holden, MD; Phone Number: 613-533-3134; Email: rachel.holdne@kingstonhsc.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 40 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• healthy
• between ages of 20 and 40

Exclusion Criteria:

• known heart disease
• known diabetes
• pregnant
• breast-feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: OTHER
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: Phosphate supplemented diet; All participants will undergo phosphate testing after following a phosphate supplemented diet for 5 days	Dietary supplement: Phosphate supplemented diet; Participants will be asked to follow a 5 day menu of 750 mg of phosphorus daily along with a daily sodium phosphorus supplement of 500 mg; Other Names: sodium phosphate
NO_INTERVENTION: Low phosphate diet; All participants will undergo phosphate testing after following a low phosphate diet for 5 days

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary phosphate excretion	Change in urinary phosphate excretion after 500 mg phosphorus challenge	3 hours

Collaborators and Investigators

• Sponsor: Clinical Evaluation Research Unit at Kingston General Hospital

Study record dates

Study Major Dates

• Study Start (ACTUAL): May 1, 2017
• Primary Completion (ANTICIPATED): September 30, 2019
• Study Completion (ANTICIPATED): September 30, 2019

Study Registration Dates

• First Submitted: July 8, 2019
• First Submitted That Met QC Criteria: July 9, 2019
• First Posted (ACTUAL): July 10, 2019

Study Record Updates

• Last Update Posted (ACTUAL): July 12, 2019
• Last Update Submitted That Met QC Criteria: July 10, 2019
• Last Verified: July 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: DMED-2031-17

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No