The relationship between ascorbate intake, in supplemental form and naturally occurring in orange juice, and urinary oxalate was assessed in 6 healthy individuals. An experimental model which allowed a differentiation between endogenously- and exogenously derived urinary oxalate was used. Twenty-four hour urine samples were collected the last day of baseline, supplemental ascorbate, and orange juice treatment periods. Oxalate load tests were administered the day following each experimental treatment. Oxalate loads consisted of 175 mg unlabeled and 18 mg 1,2-13C2 oxalic acid. The orange juice treatment was associated with higher urinary excretion of endogenously-derived oxalate, citrate, and calcium, and a higher urinary pH. Since these urinary changes were not observed during the supplemental ascorbate period, the two sources of ascorbate differentially affected key urinary components which are related to calcium oxalate nephrolithiasis.
- Orange Juice
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Nutrition and Dietetics