Scientists investigate Oxalate's role in kidney stone development

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

Inclusion Criteria: * Men and women between the ages of 18 and 60 years old. * Able to provide informed consent. * BMI between 20-30 kg/m2. * Non-tobacco users or not pregnant/breastfeeding/nursing. * Normal fasting blood comprehensive metabolic panel, complete blood count, C-reactive protein, and urinalysis. Must accurately collect two 24-hour urine collections within 20% of the appropriate ratio of creatinine (mg)/body weight (kg) for respective gender. * Healthy subjects: No history of CaOx KS or other medical conditions. * Patients with CaOx KS: Recent stone composition \> 50% CaOx; no uric acid, struvite, or carbonate apatite stone content. Must be first-time or recurrent CaOx stone former (last stone event ≤ 3 years). * Willing to not consume supplements (i.e. vitamins, Ca (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, and probiotics) for 2 weeks before the study and during the study. * Willing to abstain from vigorous exercise during the study as this may compromise immune function. * Willing to consume diets provided only by the UAB CCTS Bionutrition Core. No food allergies or intolerance to any of the foods on the study menus. * Willing to accurately collect 24-hour urine samples, and to have blood drawn throughout the study. * If on medications for KS prevention (e.g. thiazides, citrate supplementation excluding calcium citrate), patients must be on a stable dose regimen for at least 8 weeks prior to and during screening, with no changes in dosing anticipated during the study. Patients should not take allopurinol for 2 weeks prior to screening since allopurinol has antioxidant properties. Exclusion Criteria: * Failure to meet the inclusion criteria or physician refusal. * Inability to sign and read the informed consent. * Any medical, psychiatric, or social conditions that would prohibit participants from abiding by the study requirements. * BMI ˃30 kg/m2 and \<20 kg/m2 * Tobacco users or pregnant or breastfeeding/nursing women. * Abnormal fasting blood comprehensive metabolic panel, complete blood count, C-reactive protein, and urinalysis. Inaccurate 24-hour urine collections. * Healthy subjects: Currently taking or have recently taken medications within the last 3 months (i.e. antibiotics) or dietary supplements. History of KS or any medical condition that could influence absorption or excretion of oxalate. * Active illness including COVID-19, flu, common cold, fever, diarrhea, urinary tract infections, or other infections 14 days before the study and throughout the study.