The Study
Comparison of Risk Profiles, Nutrient Intake, and Kidney Function of Calcium Oxalate Stone Formers with and without Enteric Hyperoxaluria. A Matched Case-Control Study
This study looked at two groups of people who already had kidney stones and compared what was different between them, like their urine and diet. It can tell us what things tend to happen together, but it can't prove that one thing caused the other — like whether low urine pH made their kidneys worse or if their kidneys got worse and then made their urine pH low.
Analysis score
Maximum 58 for a case-control study.
Where the score came from
Some people with kidney stones have bowel problems that make their bodies absorb too much oxalate from food, which harms the kidneys.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 557 / 100
Quality score
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — even with diet changes, these patients still had high oxalate and low pH, and their kidneys were significantly weaker, suggesting their condition is harder to manage with diet alone.
- 2People with bowel problems absorbed 14.8% of oxalate vs.
- 38.9% in others.
- 4Their kidneys worked worse (eGFR 75.7 vs.
- 590.7).
- 6Lower urine pH (more acidic) meant worse kidney function: every 0.5-point drop in pH = 7.4 point drop in eGFR.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2026
Authors
Charlotte Ernsten, N. Spuck, Albrecht Hesse, Roswitha Siener
Related Content
Claims (5)
In people with calcium oxalate kidney stones and enteric hyperoxaluria, lower urine pH is linked to reduced kidney filtering capacity, with each 0.5-unit drop in pH corresponding to a 7.4 mL/min/1.73 m² decrease in estimated glomerular filtration rate.
People who form calcium oxalate kidney stones due to intestinal malabsorption absorb more oxalate from their gut (14.8%) than those who form stones for unknown reasons (8.9%), and this difference does not change when both groups eat the same low-oxalate diet.
People with calcium oxalate kidney stones caused by intestinal malabsorption have higher levels of oxalate in their urine and lower kidney function than people with kidney stones of unknown cause.
People with calcium oxalate kidney stones and enteric hyperoxaluria consistently have lower levels of citrate and magnesium in their urine and produce less urine volume than others, even when eating the same balanced diet.
When the body breaks down too much vitamin C, it produces oxalate that forms crystals in the kidneys and damages kidney tissue.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.