No contribution of ascorbic acid to renal calcium oxalate stones.
Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones due to physiological regulatory factor: gastrointestinal absorption as well as renal tubular reabsorption of AA are saturable processes, and the metabolic transformation of AA to oxalate is limited as well. Older assays for urinary oxalate favored in vitro conversion of AA to oxalate during storage and processing of the samples. Recurrent stone formers and patients with renal failure who have a defect in AA or oxalate metabolism should restrict daily vitamin C intakes to approximately 100 mg. But in the large-scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (> 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles.
Gerster
H
H
Vitamin Research Department, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
D001205:Ascorbic Acid / Q000009:adverse effects* / Q000378:metabolism / Q000493:pharmacokinetics; D002129:Calcium Oxalate / Q000032:analysis* / Q000378:metabolism; D016022:Case-Control Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007408:Intestinal Absorption; D007668:Kidney / Q000378:metabolism; D007669:Kidney Calculi / Q000737:chemistry* / Q000453:epidemiology / Q000378:metabolism; D008297:Male; D010070:Oxalates / Q000378:metabolism / Q000652:urine; D051437:Renal Insufficiency / Q000453:epidemiology / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors
D010070:Oxalates; D002129:Calcium Oxalate; D001205:Ascorbic Acid