Understanding how ascorbic acid affects kidney stone formation
Oxalate Formation From Ascorbic Acid
This study is testing how vitamin C affects the formation of kidney stones in adults with and without a history of these stones while they follow a low oxalate diet.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 136 (estimated) |
| Ages | 19 Years and up |
| Sex | All |
| Sponsor | University of Alabama at Birmingham Academic / other |
| Locations | 1 site (Birmingham, Alabama) |
| Trial ID | NCT04603898 on ClinicalTrials.gov |
What this trial studies
This research aims to investigate the role of ascorbic acid turnover in urinary oxalate excretion among adults with and without a history of calcium oxalate kidney stones. Participants will be divided into normal BMI and obese groups and will follow a controlled low oxalate diet. They will consume a stable isotope of ascorbic acid and provide urine and blood samples to measure the conversion of ascorbic acid to oxalate. The study will help clarify the relationship between dietary ascorbic acid and kidney stone formation.
Who should consider this trial
Good fit: Ideal candidates include adults aged 19 and older, both normal BMI and obese, with or without a history of calcium oxalate kidney stones.
Not a fit: Patients with a history of kidney stones not composed of calcium oxalate or those with significant food allergies may not benefit from this study.
Why it matters
Potential benefit: If successful, this study could lead to better dietary recommendations for preventing kidney stones.
How similar studies have performed: While the specific approach of using carbon-13 ascorbic acid is novel, related studies have explored dietary impacts on kidney stone formation with varying degrees of success.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Able to provide informed consent * For stone formers: composition of most recent stone \> 50% calcium oxalate, no uric acid component * For stone formers: first time or recurrent calcium oxalate stone former with stone event within the prior 3 years * Two 24-hour urine collections with urinary 24-hour creatinine excretion within 20% of appropriate ratio of creatinine (mg) / body weigh (kg) for gender * Willingness to stop supplements (vitamins, Calcium (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics) for 2 weeks before start and during study * Willingness to not undertake vigorous exercise during the study * Normal fasting blood Comprehensive Metabolic Panel (CMP) * Willingness to ingest menus prepared in Clinical Research Unit at University of Alabama at Birmingham * No food allergies or intolerance to any of the foods in study menus * If on medications for stone prevention (e.g. thiazides, citrate supplementation excluding calcium citrate), they should have been on a stable dose regimen for at least 8 weeks prior to and during screening, with no changes in dosing anticipated during study protocol. If on allopurinol for stone prevention, stop it for 2 weeks prior to screening and this will not be administered during the study as it has anti-oxidant properties. Exclusion Criteria: * Diabetes * Gout * Hypertension * Estimated Glomerular Filtration Rate (eGFR) less than 60ml/min/1.73m2 * Primary hyperoxaluria * Nephrotic syndrome * Enteric hyperoxaluria * Renal tubular acidosis * Primary hyperparathyroidism * Liver disease * Auto-immune disorder * Neurogenic bladder * Urinary diversion * Bariatric surgery * Active malignancy or treatment for malignancy within 12 months prior to screening * Pregnancy * Breastfeeding/nursing individuals * Females of child bearing age who are not able to use an effective method of birth control during the study * Mental/medical condition that is likely to impede successful study completion * Illness including flu/common cold/fever 14 days before study and during study * Diarrhea or other abnormal gastrointestinal event (e.g. abnormal bowel movements) 14 days before study or during study * Abnormal fasting CMP
Where this trial is running
Birmingham, Alabama
- University of Alabama at Birmingham — Birmingham, Alabama, United States (Recruiting)
Study contacts
- Principal investigator: John Knight, PhD — University of Alabama at Birmingham
- Study coordinator: Demond Wiley
- Email: kidneystone@uabmc.edu
- Phone: 2059343671
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.