Vitamin C's hidden role in kidney stones revealed

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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