• 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.