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Completed

NCT Number: NCT04051346

Dietary Oxalate and Innate Immunity in Kidney Stone Disease

This study will test whether oxalate stimulates urinary crystals and impacts the immune system in healthy subjects using two controlled diets (low and high oxalate).

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Key information

Conditions

Kidney Stone Calculi Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Kidney Calculi Kidney Diseases Male Urogenital Diseases Nephrolithiasis Pathological Conditions, Anatomical Pathological Conditions, Signs and Symptoms Urinary Calculi Urogenital Diseases Urolithiasis Urologic Diseases

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Alabama at Birmingham

Birmingham, Alabama, 35233, United States

About this study

Oxalate is a small molecule found in plants and plant-derived food. It has been shown that meals containing high amounts of oxalate can increase urinary oxalate excretion, which is a risk factor for calcium oxalate kidney stones (CaOx KS). Small increases in oxalate can stimulate urinary crystals to form which can elicit an immune response. This study consists of having healthy subjects consume both low and oxalate enriched diets to evaluate the effect of oxalate on urinary crystals and immune responses. Participants will receive a low or high oxalate diet for 4 days prior to having a wash out period for 6 days. Participants will then crossover to the opposite oxalate diet for four more days.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy subjects (men and women) between the ages of 18 and 60 years of age
  • No calcium oxalate kidney stones or other medical conditions
  • Normal comprehensive metabolic panel (CMP)
  • Non tobacco users
  • Not pregnant
  • BMI between 20-30 kg/m2
  • Willing to abstain from vigorous exercise and vitamins/supplements during the study
  • Willing to consume only provided diets, accurately collect 24-hour urine samples, and have blood drawn

Exclusion criteria

  • Inability to sign and read the informed consent
  • Any medical, psychiatric, or social conditions that would prohibit participants from abiding by the study requirements
  • Physician refusal
  • Pregnant women
  • Active medical problems
  • History of kidney stones or any medical condition that could influence absorption or excretion of oxalate
  • Tobacco users
  • Taking medications or dietary supplements
  • BMI >30 or <20

Treatment and study plan

Low Oxalate Diet

Dietary Supplement

Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, to exercise strenuously, or to consume food or drink that is not provided to them.

High Oxalate Diet

Dietary Supplement

Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, to exercise strenuously, or to consume food or drink that is not provided to them.

Primary outcomes

  1. Urinary Oxalate Excretion

    Time frame: Days 4 and 14

    Twenty-four hour urinary oxalate will be reported as mg/day.

  2. Crystalluria

    Time frame: Day 4 and 14

    Crystalluria will be reported as particles/ml.

  3. Number of Participants With Monocyte Cellular Energetics

    Time frame: Days 4 and 14

    Cellular energetic oxygen consumption traces will be examined.

Secondary outcomes

  1. Number of Participants With Monocyte Transcriptomics

    Time frame: Days 4 and 14

    Monocyte cellular transcriptomics will be determined using RNA sequencing (mRNA).

Sponsors and collaborators

Lead sponsor

University of Alabama at Birmingham

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Important dates

Study start
2021
Primary completion
2025
Study completion
2025
First posted
Aug 9, 2019
Registry last updated
Jun 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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