Journal of endourology
July 31, 2026 · via Europe PMC
The Effect of Vitamin C Supplements on Urinary Stone Risk: A Systematic Review and Meta-Analysis.
Farkouh A, Seibly E, Buell MI, Jhang D, Amasyali AS, Okhunov Z, Baldwin DD.
AI summary — for doctors, generated from the abstract only
Vitamin C supplementation significantly raised urinary oxalate in both stone formers and non-stone formers, which may contribute to stone formation.
What was studied
Systematic review and meta-analysis of interventional studies (nine included from 808 titles; searches 1965 to February 2023) on the effect of vitamin C on 24-hour urinary oxalate, citrate and calcium.
Key findings
- Pooled urinary oxalate increased versus baseline (mean difference 9.72 mg/24 h)
- The abstract's results for citrate, calcium and the placebo-controlled comparisons are cut off
- The authors conclude the oxalate rise applies to both stone formers and non-stone formers
Clinical relevance
Stone formers and their clinicians may want to review vitamin C supplement use, since higher oxalate excretion is a recognised stone risk factor.
Who should care
Limitations
Only nine studies, and the abstract is truncated so confidence intervals and heterogeneity are not shown. Urinary oxalate is a surrogate, not actual stone events, and searches ended in 2023.
Vitamin C supplements raise urinary oxalate, a plausible but unproven link to stone risk.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Introduction and objective
With the increased intake of vitamin C supplements during the COVID pandemic, physicians have reported an increase in stone incidence and complexity. The purpose of this systematic review and meta-analysis was to study the effect of vitamin C supplements on urine parameters associated with stone formation.
Methods
A comprehensive review was performed to retrieve relevant articles published from 1965 until February 2023. Studies were included if they were interventional studies investigating the effect of vitamin C supplements on 24-hour urinary parameters (oxalate, citrate, and calcium) in both stone formers (SFs) and nonstone formers (NSFs), compared with either baseline values or a placebo group. Meta-analyses were performed to calculate the mean difference (MD) measuring the effect of vitamin C supplements on these parameters.
Results
The initial database search yielded 808 titles and after rigorous screening, nine studies were included. Pooled analysis revealed a significant increase in urinary oxalate after vitamin C supplementation compared with baseline (MD = 9.72 mg/24 h; p p p < 0.05 for all). Analyses of studies reporting on 24-hour urinary citrate or calcium revealed no significant effect of vitamin C on either parameter.
Conclusions
Vitamin C supplements significantly increase urinary oxalate excretion in both SFs and NSFs. This may contribute to stone formation and may worsen stone presentation among those who consume these supplements.
DOI
10.1177/08927790261471733
PMID
42535313
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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