Narrative reviewindependent cross-checkabstract only checked I-VEG-07 standard review
Where urinary oxalate comes from
Contribution of Dietary Oxalate and Oxalate Precursors to Urinary Oxalate Excretion.
Overview
Crivelli JJ et al.. Nutrients 2020 · PMID 33379176 · DOI 10.3390/nu13010062
Dietary oxalate contributes to urinary oxalate, modified by gut bacteria and calcium.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Review oxalate
- How was the study done?
Review
- How many people, animals or samples were studied?
Not applicable
- What was actually found?
Diet contributes; gut bacteria modify
- How large was the observed effect?
Not applicable
- What do the results mean in everyday life?
Calcium with meals and moderation help stone formers.
- What are the study's limitations?
Narrative
- What does it say about Elawady's specific claim?
Context
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Cannot quantify stone risk.
Scientific in-depth review
1. Full reference
- Authors
- Crivelli JJ et al.
- Journal
- Nutrients
- Year
- 2020
- Identifier
- PMID 33379176 DOI 10.3390/nu13010062
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Authors report consulting for several therapeutics companies
2. Research question
Dietary oxalate, precursors and urinary oxalate.
3. Study design and population
- Study design
- Narrative review – Narrative review
- Population
Not applicable
- Country
Not applicable
- Period
Not applicable
- Sample size
Not applicable
- Inclusion and exclusion criteria
Not applicable
4. Methods and endpoints
- Exposure / intervention
Dietary oxalate, vitamin C, gut bacteria
- Comparator
Not applicable
- Endpoints
Urinary oxalate
- Statistical methods
Not applicable
5. Actual results
- Results
Net GI oxalate absorption influences urinary oxalate; oxalate-degrading bacteria (Oxalobacter formigenes) may mitigate risk; vitamin C main precursor.
- Absolute risks
not reported
- Authors' conclusion
Reviews role of dietary oxalate and precursors in stone disease.
6. Strengths
- Expert review
7. Weaknesses
- Narrative
- Industry consulting
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- not assessable
- Rationale
Narrative.
9. Assessment of the statistical interpretation
Not applicable.
10. Relevance to the specific claim
Mechanistic context for C-VEG-05.
11. Independent contrary findings
None.
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Context.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | not assessable |
| Precision of results | not applicable |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
None.
15. Linked fact checks
- Oxalate-rich greens (spinach, beet greens, chard) cause kidney stones; each 100 mg of dietary oxalate raises urinary oxalate by about 2.7 mg. – Studies with mixed or unclear results