Assessing How the Body Responds to Increased Phosphate Intake, and How This Response Depends on Age and Sex.

NCT07149337 | Not Yet Recruiting DMC

• 1 other identifier: 2024-02538
• Study Type: interventional
• Target: 40
• Locations: 0 countries
• Sites: N/A

Brief Summary

Kidney function declines with age and this could affect phosphate balance after an acute phosphate load (increased phosphate intake). In daily life, we regularly experience acute phosphate loads through our diet. The aim of this clinical study is to determine whether the body's response to increased phosphate intake changes with age and whether there are sex differences in this response.

Conditions

Aging; Kidney Disease; Mineral Metabolism

Keywords

Phosphate homeostasis and aging; Oral phosphate challenge

Outcome Measures

Primary Outcomes (1)

• Phosphate in plasma

  Phosphate in plasma 4 hours after the oral phosphate load shows age differences

  The primary outcome will be measured 5 hours after the first blood collection on the day of the study and 4 hours after ingesting the oral phosphate load.

Study Arms (1)

Oral phosphate load

EXPERIMENTAL

Participants will eat a standard phosphate dinner. The next morning, after consuming a standard phosphate breakfast, they will ingest a phosphate load (558 mg phosphorus) and provide blood and urine samples for nine hours.

Other: Oral phosphate load

Interventions

Oral phosphate load OTHER

Participants ingest an oral phosphate load containing 558 mg of phosphorus once.

Oral phosphate load

Eligibility Criteria

• Age: 25 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy volunteers 18-25 and 63-70 years old
• ≥ BMI \< 26 kg/m2
• ≥ phosphate in plasma ≤ 1.45 mM
• ≥ calcium in plasma ≤ 2.50 mM
• ≥ PTH in plasma ≤ 65 pg/ml
• eGFR ≥ 60 ml/min/1-73 m2
• ≥ Systolic blood pressure ≤ 140 mmHg
• ≥ Diastolic blood pressure ≤ 85 mmHg
• No hematuria and no acute urinary tract infection
• Ability and willingness to participate in the study
• Voluntary signed inform consent

You may not qualify if:

• Diabetes mellitus
• Pregnancy
• History of kidney stones
• History of parathyroidectomy
• History of anorexia nervosa
• History of bulimia
• History of solid organ transplantation.
• Nephrolithiasis
• Sarcoidosis
• Chronic pancreatitis
• Chronic diarrhea
• Chronic liver disease
• Complete distal renal acidosis (dRTA)
• Cystinuria
• Hypo- or hyperaldosteronism

Sponsors & Collaborators

• University of Zurich: lead

MeSH Terms

Conditions

Kidney Diseases

Condition Hierarchy (Ancestors)

Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases

Central Study Contacts

Carsten A Wagner, Prof. MD

CONTACT

41 44 635 50 23; carsten.wagner@physiol.uzh.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 22, 2025
• First Posted: September 2, 2025
• Study Start: September 30, 2025
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): September 1, 2027
• Last Updated: September 2, 2025

Record last verified: 2025-08