Effect of Weight Loss on Urinary Oxalate Excretion in Obese Calcium Oxalate Kidney Stone Formers

Summary

This protocol seeks to determine if weight reduction with the Optifast VLCD program leads to reduced contribution of endogenous oxalate synthesis and dietary oxalate absorption to the urinary oxalate pool in obese calcium oxalate stone formers.

Conditions

• Kidney Stone

Interventions

DIETARY_SUPPLEMENT

Low Oxalate Diet before Weight Loss

Subjects will be instructed to ingest a controlled diet low in oxalate for a total of 6 days. 2 x 24 hour urines will be collected on days 3 and 4.

DIETARY_SUPPLEMENT

Oral load of oxalate and sucralose before Weight Loss

Subjects will ingest 100mg carbon-13 oxalate, and 1 gram of sucralose on day 5 of the 6-day low oxalate diet phase. Following the oral load, blood and urine will be collected every 30 minutes and hourly, respectively

DIETARY_SUPPLEMENT

Optifast VLCD Program

Subjects will go on a 10-week Intestive level Optifast VLCD weight loss program

DIETARY_SUPPLEMENT

Optifast VLCD Transition Phase

After completion of the 10-week Optifast VLCD Program, subjects will be weaned off the Optifast products for 4 weeks.

DIETARY_SUPPLEMENT

Low Oxalate Diet after Weight Loss

Subjects will be instructed to ingest a controlled diet low in oxalate for a total of 11 days and collect 2 x 24 hour urines on days 8 and 9

DIETARY_SUPPLEMENT

Oral load of oxalate and sucralose after Weight Loss

Subjects will ingest 100mg carbon-13 oxalate, and 1 gram of sucralose on day 10 of the 11-day low oxalate diet phase. Following the oral load, blood and urine will be collected every 30 minutes and hourly, respectively

Sponsors & Collaborators

• University of Texas Southwestern Medical Center

  collaborator OTHER

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

  collaborator NIH

• University of Alabama at Birmingham

  lead OTHER

Principal Investigators

• Dean Assimos, MD · University of Alabama at Birmingham

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

19 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2021-12-03

Primary Completion

2025-12-31

Completion

2026-12-31

Countries

• United States

Study Locations