What We Are
OxalateWatch is a dietary reference tool for kidney stone patients. We are a data editorial team, not a medical practice: our job is to present lab-measured nutrition data in a clear, searchable format. We do not provide medical advice, and every food page states this explicitly. The value of the site rests on the accuracy and transparency of the data itself — which is why this page documents exactly where the numbers come from and how they are handled.
How We Build the Database
Source: Harvard T.H. Chan SPH Oxalate Database (2024)
Every oxalate value originates from the most comprehensive publicly available oxalate dataset, compiled by Dr. John Knight at the University of Alabama at Birmingham and published through the Harvard T.H. Chan School of Public Health and the Oxalosis & Hyperoxaluria Foundation (OHF). The dataset covers over 1,200 foods with laboratory measurements.
Measurement method: ion chromatography
The values in the source dataset were produced by ion chromatography — a direct laboratory measurement technique — rather than by estimation or modeling from similar foods. This is why the site describes its data as "lab-measured, not estimated." Each food page links back to this methodology so the claim can be checked.
Nutrition complement: USDA FoodData Central
Sodium, protein, calcium, and water content come from the USDA FoodData Central database (SR Legacy 2018 and Foundation Foods). Where a food's USDA match is still being completed, the page states that the oxalate figure is solid while the other nutrients remain pending — we do not publish guessed values.
Thresholds: aligned with NKF / AUA guidance
The three ratings — Low Oxalate (under 25 mg per serving), Moderate Oxalate (25-99 mg), High Oxalate (100 mg or more) — follow the oxalate thresholds used in clinical practice and consistent with National Kidney Foundation (NKF) and American Urological Association (AUA) guidance on dietary oxalate for stone formers.
Verification and corrections
Values are cross-checked against the source dataset on every update, and serving sizes are stated per food so the number is reproducible. If a value is ever found to be wrong, we correct it and log the change in our corrections page rather than silently editing.
What the Ratings Mean
🟢 Low Oxalate — under 25 mg per serving. Generally well-tolerated by most kidney stone patients; suitable for regular eating.
🟡 Moderate Oxalate — 25-99 mg per serving. Fits into a stone diet with portion control and balance; pair with calcium-rich foods.
🔴 High Oxalate — 100 mg or more per serving. High-oxalate foods that most stone formers should limit or avoid.
Oxalate is the primary rating dimension on this site. Sodium and animal protein are flagged as separate warnings because they affect stone risk through independent mechanisms (urinary calcium and uric acid, respectively). Dietary calcium is flagged as a positive: it binds oxalate in the gut.
Limitations We State Openly
- Individual variation: oxalate tolerance varies by person, stone type, and medication. The database is a reference, not a prescription.
- Serving-size dependence: all ratings are per stated serving. The same food at double the serving roughly doubles the oxalate.
- Not a medical resource: we do not diagnose, treat, or advise on medication. A clinician or registered dietitian should interpret any diet change.
Update Process
The database was last verified on 2026-07-16. Updates are published when the source dataset or USDA matches are revised, and each revision is logged. This site is a dietary reference tool, not a medical resource — we present data, and we tell you where it came from.
Found a discrepancy? Report it and we will investigate.