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Cited by 176Kidney Stones and Urolithiasis TreatmentsVitamin C and Antioxidants ResearchGout, Hyperuricemia, Uric Acid

Effect of vitamin C supplements on urinary oxalate and pH in calcium stone-forming patients

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Baxmann, Alessandra Calábria, de O.G. Mendonça, Claudia, Heilberg, Ita Pfeferman·2003·Kidney International
DOI 10.1046/j.1523-1755.2003.00815.x
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Abstract

Background The contribution of ascorbate to urinary oxalate is controversial. The present study aimed to determine whether urinary oxalate and pH may be affected by vitamin C supplementation in calcium stone-forming patients.Methods Forty-seven adult calcium stone-forming patients received either 1 g (N=23) or 2 g (N=24) of vitamin C supplement for 3 days and 20 healthy subjects received 1 g. A 24-hour urine sample was obtained both before and after vitamin C for calcium, oxalate, magnesium, citrate, sodium, potassium, and creatinine determination. The Tiselius index was used as a calcium oxalate crystallization index. A spot fasting morning urine sample was also obtained to determine the urinary pH before and after vitamin C.Results Fasting urinary pH did not change after 1 g (5.8 +/- 0.6 vs. 5.8 +/- 0.7) or 2 g vitamin C (5.8 +/- 0.8 vs. 5.8 +/- 0.7). A significant increase in mean urinary oxalate was observed in calcium stone-forming patients receiving either 1 g (50 +/- 16 vs. 31 +/- 12 mg/24 hours) or 2 g (48 +/- 21 vs. 34 +/- 12 mg/24 hours) of vitamin C and in healthy subjects (25 +/- 12 vs. 39 +/- 13 mg/24 hours). A significant increase in mean Tiselius index was observed in calcium stone-forming patients after 1 g (1.43 +/- 0.70 vs. 0.92 +/- 0.65) or 2 g vitamin C (1.61 +/- 1.05 vs. 0.99 +/- 0.55) and in healthy subjects (1.50 +/- 0.69 vs. 0.91 +/- 0.46). Ancillary analyses of spot urine obtained after vitamin C were performed in 15 control subjects in vessels with or without ethylenediaminetetraacetic acid (EDTA) with no difference in urinary oxalate between them (28 +/- 23 vs. 26 +/- 21 mg/L), suggesting that the in vitro conversion of ascorbate to oxalate did not occur.Conclusion These data suggest that vitamin C supplementation may increase urinary oxalate excretion and the risk of calcium oxalate crystallization in calcium stone-forming patients.

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Authors
Baxmann, A. C., de O.G. Mendonça, C., & Heilberg, I. P.
Affiliations
Universidade Federal de São Paulo (BR)
Corresponding author
Heilberg, Ita Pfeferman
ORCID
Heilberg, Ita Pfeferman
Venue
Kidney International
Publisher
Elsevier BV
Published
2003-03
Volume
63
Issue
3
Pages
1066-1071
ISSN
0085-2538 (ISSN-L)
DOI
10.1046/j.1523-1755.2003.00815.x
OpenAlex
W2000927595
Cited by
176
References
38
Citations by year
2026: 10 · 2025: 10 · 2024: 12 · 2023: 11 · 2022: 17 · 2021: 8 · 2020: 10 · 2019: 6 · 2018: 5 · 2017: 8 · 2016: 9 · 2015: 6 · 2014: 10 · 2013: 7 · 2012: 6
FWCI
5.40
Type
journal article
Language
en
Open access
Licence
Locations
  • Kidney International (publishedVersion)
  • PubMed (publishedVersion)
  • Americanae (AECID Library) (publishedVersion, other-oa)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, other-oa)
Topics
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Kidney Stones and Urolithiasis Treatments
  • Health Sciences › Nursing › Nutrition and Dietetics › Vitamin C and Antioxidants Research
  • Health Sciences › Medicine › Nephrology › Gout, Hyperuricemia, Uric Acid
Keywords
vitamin C supplementation, vitamin C, urinary oxalate, urine pH, calcium oxalate stones, calcium oxalate crystallization, 24-hour urine analysis, urinary citrate, magnesium, sodium, potassium, creatinine, dietary oxalate
MeSH terms
Adult, Antioxidants, Ascorbic Acid, Calcium, Calcium Oxalate, Crystallization, Female, Humans, Hydrogen-Ion Concentration, Kidney Calculi, Male, Middle Aged, Risk Factors

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