Vitamin C's Impact on Kidney Stones
Recruiting in Palo Alto (17 mi)
Age: 18+
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: University of Alabama at Birmingham
Must be taking: Thiazides, Citrate supplementation
Disqualifiers: Diabetes, Hypertension, Gout, others
No Placebo Group
Trial Summary
What is the purpose of this trial?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.
Will I have to stop taking my current medications?
The trial requires participants to stop taking supplements like vitamins, calcium, and other minerals for 2 weeks before and during the study. If you are on medications for stone prevention, you must have been on a stable dose for at least 8 weeks before the study, and if you take allopurinol, you need to stop it 2 weeks before the study.
What data supports the effectiveness of the treatment Carbon-13 Ascorbic Acid Oral Load for kidney stones?
Some studies suggest that high doses of vitamin C do not increase the risk of kidney stones due to the body's ability to regulate vitamin C absorption and conversion to oxalate. In fact, a large study found that people with high vitamin C intake had a lower risk of kidney stones.
12345Is Vitamin C safe for people with kidney stones?
Vitamin C is generally safe for healthy people, but high doses may increase the risk of kidney stones in those with existing kidney issues or a history of stones. People with kidney problems should limit their intake to about 100 mg per day.
23678How does the drug Carbon-13 Ascorbic Acid Oral Load differ from other treatments for kidney stones?
Carbon-13 Ascorbic Acid Oral Load is unique because it uses a labeled form of vitamin C to study its impact on kidney stones, focusing on how the body processes vitamin C and its potential role in stone formation. Unlike other treatments, this approach helps researchers understand the metabolic pathways and risks associated with vitamin C intake, which is still debated in the context of kidney stones.
23456Eligibility Criteria
This trial is for adults with normal BMI or obese, non-stone formers and calcium oxalate stone formers who haven't had certain health conditions like diabetes, hypertension, or severe kidney issues. Participants must not be on specific medications that could affect the study results and should agree to follow a controlled diet without supplements or vigorous exercise during the study.Inclusion Criteria
Able to provide informed consent
Your fasting blood test results are normal for a comprehensive metabolic panel (CMP).
Willingness to not undertake vigorous exercise during the study
+7 more
Exclusion Criteria
Your kidney function is too low (eGFR less than 60ml/min/1.73m2).
I have been diagnosed with primary hyperoxaluria.
I have high blood pressure.
+19 more
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
1-2 weeks
1 visit (in-person)
Dietary Equilibration
Participants consume a controlled diet low in oxalate and ascorbic acid for two days to equilibrate
2 days
1 visit (in-person)
Treatment
Participants ingest an oral load of carbon-13 ascorbic acid and undergo serial blood and urine collections
4 days
4 visits (in-person)
Follow-up
Participants are monitored for safety and effectiveness after treatment
1-2 weeks
Participant Groups
The study aims to understand how much vitamin C (ascorbic acid) from our diet turns into oxalate in the urine, which can contribute to kidney stones. It involves following a special low-oxalate diet and taking a stable isotope of ascorbic acid orally while researchers measure its turnover using advanced techniques.
1Treatment groups
Experimental Treatment
Group I: Controlled Dietary StudyExperimental Treatment2 Interventions
Subjects will consume a controlled diet (low in oxalate and ascorbic acid) for six days. After two days of equilibration, subjects will provide a blood sample and ingest an oral load of ascorbic acid (1 mg/kg) with breakfast on Day 3. The following day (Day 4), serial blood and urine collections will occur. On Days 5 through 7, subjects will complete a 24-hr urine collection and blood draw.
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
University of Alabama at BirminghamBirmingham, AL
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Who Is Running the Clinical Trial?
University of Alabama at BirminghamLead Sponsor
References
Is it safe to prescribe ascorbic acid for urinary acidification in stone-forming patients with alkaline urine? [2020]Label="OBJECTIVE" NlmCategory="OBJECTIVE">To study the effect of ascorbic acid (AA) supplementation on urinary pH, metabolic stone workup parameters, and development of de novo urolithiasis in stone-forming patients.
Relative hyperoxaluria, crystalluria and haematuria after megadose ingestion of vitamin C. [2019]Long-term or high-dosage consumption of vitamin C may play a role in calcium oxalate kidney stone formation. The present study was undertaken to determine the biochemical and physicochemical risk factors in a male subject who developed haematuria and calcium oxalate crystalluria after ingestion of large doses of ascorbic acid for 8 consecutive days.
No contribution of ascorbic acid to renal calcium oxalate stones. [2022]Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones due to physiological regulatory factor: gastrointestinal absorption as well as renal tubular reabsorption of AA are saturable processes, and the metabolic transformation of AA to oxalate is limited as well. Older assays for urinary oxalate favored in vitro conversion of AA to oxalate during storage and processing of the samples. Recurrent stone formers and patients with renal failure who have a defect in AA or oxalate metabolism should restrict daily vitamin C intakes to approximately 100 mg. But in the large-scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (> 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles.
Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones. [2018]Previous studies of vitamin C and kidney stones were conducted mostly in men and either reported disparate results for supplemental and dietary vitamin C or did not examine dietary vitamin C.
Effect of vitamin C supplements on urinary oxalate and pH in calcium stone-forming patients. [2016]The contribution of ascorbate to urinary oxalate is controversial. The present study aimed to determine whether urinary oxalate and pH may be affected by vitamin C supplementation in calcium stone-forming patients.
Ascorbic Acid Supplements and Kidney Stones Incidence Among Men and Women: A systematic review and meta-analysis. [2020]The relationship of ascorbic acid (AA) supplements and risk of kidney stones among men and women is controversial. This systematic evaluation was performed to obtain comprehensive evidence about the relationship of AA supplements and risk of kidney stones among men and women.
Ascorbic acid is an abettor in calcium urolithiasis: an experimental study. [2013]Two sets of animal experiments using guinea pigs were planned to evaluate the effect of ascorbic acid supplementation on the lithogenic process. In the first set of experiments, 10, 40, and 60 mg doses of ascorbic acid/100g body weight/day were given for 105 days. Neither of the ascorbic acid doses given induced crystalluria, calcification or stone formation, thereby confirming our previous findings that ascorbic acid in the doses used by clinicians does not cause urolith formation. In the second set of experiments, ascorbic acid was supplemented in hypercalciuric (induced by calcium carbonate feeding) and hyperoxaluric (induced by sodium oxalate feeding) animals for 45 days. The results indicated that it exacerbated the calcification process in renal and bladder tissue.
Safety of high-level vitamin C ingestion. [2013]Reports suggesting that gram doses of ascorbic acid are beneficial for the prevention and treatment of several disorders have led to widespread ingestion of vitamin C supplements. Possible adverse health effects of this practice have, therefore, received considerable scrutiny. Of major concern has been the influence of ingesting gram amounts of ascorbic acid on renal calcium oxalate stones, systemic conditioning, uricosuria, vitamin B12 destruction, mutagenicity, and iron overload. Despite contradictory reports, the consensus from an extensive literature is that these adverse health effects are not induced in healthy persons by ingesting large doses of ascorbic acid. Possible interactions of ascorbic acid with other nutrients and physiological processes may be of importance to human health and, therefore, merit further research. The ingestion of large doses of ascorbic acid is contraindicated in cases of renal insufficiency, chronic hemodialysis patients, unusual forms of iron overload, and oxalate stoneformers.