NCT04603898

Oxalate Formation From Ascorbic Acid

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 136 (estimated)
• Sponsor: University of Alabama at Birmingham · Academic / Other
• Sex: All
• Age: 19 Years
• Healthy volunteers: Accepted

Summary

The purpose of this basic research study is to determine the contribution of endogenous ascorbic acid (AA) turnover to urinary oxalate excretion in both normal BMI and obese adult non-stone formers and calcium oxalate stone formers. The studies proposed will use diets of known nutrient composition, a stable isotope of ascorbic acid (13C6-AA) and mass spectrometric techniques to quantify ascorbic acid turnover to oxalate.

Detailed description

The purpose of this basic research study is to determine the contribution of endogenous ascorbic acid (AA)turnover to urinary oxalate excretion in both normal BMI and obese adult non-stone formers and calcium oxalate stone formers. The studies proposed will use diets of known nutrient composition, a stable isotope of AA, 13C6-AA, and mass spectrometric techniques to quantify AA turnover to oxalate. Adults (≥19 years) with and without a history of calcium oxalate kidney stone disease will be recruited from within the greater Birmingham area, and divided into normal BMI (BMI\<25 kg/m2) and obese (BMI≥30 kg/m2) groups. Following consent, subjects will meet with a dietitian to ensure willingness to consume controlled diets, and provide fasted blood and 2 x 24 hour urine specimens to determine general health status and adequacy of 24-hour urine collections, respectively. Eligible subjects will consume a low oxalate controlled diet for 6 days, which will involve 2 days of dietary equilibration followed by oral ingestion of 1 mg/kg carbon-13 AA with breakfast on day 3 and subsequent collection of 4 consecutive 24-hour urine specimens. After the carbon-13 AA load, subjects will return each morning to the Clinical Research Unit for a fasted blood draw, to drop off their 24-hour urine collection, and receive their prepared food. In addition, on day 4, 24 hours after ingesting carbon-13 AA, subjects will collect hourly urine and 1/2 hourly blood samples for 5 hours in the Clinical Research Unit.

Conditions

• Kidney Stone

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Low Oxalate Diet	Subjects will be instructed to ingest a controlled diet low in oxalate for a total of 4 days
DIETARY_SUPPLEMENT	Carbon-13 Ascorbic Acid Oral Load	Subjects will be instructed to ingest 1mg/kg of carbon-13 ascorbic acid at breakfast, 2 days after initiating the low oxalate controlled diet.

Timeline

• Start date: 2021-11-15
• Primary completion: 2026-08-01
• Completion: 2026-12-01
• First posted: 2020-10-27
• Last updated: 2026-03-09

Locations

1 site across 1 country: United States