Obesity and Endogenous Oxalate Synthesis

University of Alabama at Birmingham58 enrolled

Overview

The goal of this study is to determine if obesity is associated with increased endogenous oxalate synthesis as assessed by urinary oxalate excretion, which is a known risk factor for calcium oxalate kidney stones. The study will recruit adult participants without history of kidney stones. Participants will * Ingest fixed diets containing low amounts of oxalate for 4 days * Collect 24-hr urine samples during the fixed diet

In this study the investigators propose to measure the excretion of urinary oxalate on a fixed diet with controlled amounts of oxalate, in individuals of varying body sizes without history of kidney stones. The 24-hr urinary oxalate excretion on such a low-oxalate normal calcium fixed diet is determined to be an appropriate surrogate for endogenous oxalate synthesis. Screening phase. The study will enroll 60 individuals without history of kidney stones (30 males/30 females) at the University of Alabama at Birmingham (UAB). Screening will include blood complete metabolic profile, 24-hr urine specimens collected at home on self-selected diets and anthropometric measurements. Dietary phase Participants will ingest a low-oxalate (\<60 mg/day), normal calcium (1000 mg/day) fixed diet for 4 consecutive days, collect three 24-hr urines after 1 day of dietary equilibration and have a fasted blood draw on day 5.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Obesity

Interventions

Normal IndividualsDIETARY_SUPPLEMENT

Controlled Dietary phase: Low oxalate fixed diet 4 days of fixed normal calorie diet with low oxalate (\< 60 mg/day), normal calcium (800-1200 mg/day)

Eligibility

Sex: ALLMin age: 19 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria Age 19-70 yrs Body Mass Index \> 18.5 kg/m2 Normal fasting serum electrolytes on comprehensive metabolic profile Willing to ingest fixed diets Exclusion Criteria Chronic Kidney Disease, estimated glomerular filtration rate \< 60 ml/mn/1.73m2 Primary hyperoxaluria Liver, endocrine or renal diseases or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results, including: Cystic fibrosis, Cystinuria, Uric acid stone former, Nephrotic syndrome, Sarcoidosis, Renal tubular acidosis, Primary hyperparathyroidism, Neurogenic bladder, Urinary diversion Pregnancy or breast-feeding Incompatible dietary requirements with the study, food allergies or intolerance to any of the foods in study menus Active malignancy or treatment for malignancy within 12 months prior to screening Utilization of immunosuppressive medication Uncontrolled Hypertension or diabetes

Locations (1)

University of Alabama at Birmingham

Birmingham, Alabama, United States

Outcomes

Primary Outcomes

Urinary Oxalate Excretion

Mean Urinary oxalate excretion from three 24 hour urine collections on the fixed diet (mg/day)

Time frame: 3 days on the fixed diet

Secondary Outcomes

Urinary Glycolate Excretion

mean of three 24-hr urinary glycolate collected on the fixed diet (mg/day)

Time frame: 3 days on fixed diet

Urinary Creatinine Excretion

mean of there 24hr urinary creatinine excretion on the fixed diet ( g/day)

Time frame: 3 days on the fixed diet

Data from ClinicalTrials.gov

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