Oxalate Formation From Ascorbic Acid

Launched by UNIVERSITY OF ALABAMA AT BIRMINGHAM · Oct 21, 2020

Keywords

ClinConnect Summary

This clinical trial is studying how ascorbic acid (vitamin C) in our bodies might affect the formation of oxalate, a substance that can cause kidney stones. Researchers want to understand how this process works in both people who have never had kidney stones and those who have had calcium oxalate stones. Participants will follow a specific diet and take a special form of vitamin C to help measure how much ascorbic acid is turning into oxalate.

To take part in this study, you need to be an adult who can give informed consent. If you've had a kidney stone, it should be mostly calcium oxalate, and you should have had a stone event in the last three years. Participants must be willing to stop taking certain supplements and avoid vigorous exercise during the study. You will eat meals prepared for the research, and your health will be monitored closely. It’s important to note that certain medical conditions, like diabetes or liver disease, may prevent you from participating. If you fit the criteria, this study could help improve our understanding of kidney stone formation and how to prevent it.

Gender

ALL

Eligibility 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