Is Sourdough Bread Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 slice (28 g)
Verdict: 🟢 Safe
Per 100g: 3.6 mg
Data: Harvard T.H. Chan SPH (2024)
Here's the takeaway: Sourdough Bread earns a Safe rating (🟢) at 1 mg oxalate per serving. Being under 25 mg means it fits comfortably in everyday eating. Keep your usual habits — adequate fluids and calcium in meals — and Sourdough Bread poses no special concern.
Putting Sourdough Bread in context: it lands well below the category average of 14 mg. In the database, 84% of grains & pasta (170 of 201) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical grains & pasta here averages 14 mg oxalate per serving, so Sourdough Bread runs 93% below that baseline. That places it among the lower-oxalate options in its category. Why this matters: the gap between two Safe foods can be wide — one may hold 5 mg oxalate while another sits at 24 mg. The lower one leaves more room in your day. See all grains & pasta rated Safe for a full side-by-side.
Why does the safe threshold matter?
The 25 mg per serving threshold is based on clinical guidance for kidney stone patients. Harvard's lab data (2024) provides the most reliable oxalate measurements available — no database estimates, direct lab analysis. Sourdough Bread comes in at 1 mg oxalate per 1 slice (Safe) in the measured database.
Can I eat this food every day?
If it's in the Safe zone (under 25 mg/serving), yes — it can be a regular part of your diet. For Caution or Avoid foods, frequency matters. Rotate them with lower-oxalate options throughout the week. For context, Sourdough Bread measures 1 mg per 1 slice, rated Safe.
Where does the oxalate data come from?
The numbers come from Harvard T.H. Chan SPH's 2024 laboratory measurements, published through the OHF database. Direct lab analysis, which is why they're treated as the reference values for food oxalate. Applied to Sourdough Bread: 1 mg oxalate per 1 slice — Safe per Harvard (2024).
Should I also check sodium and calcium?
Definitely. Oxalate is only part of the story — high sodium raises calcium in urine, and dietary calcium (from food, not pills) binds oxalate in the gut. The food's main page lists both, so it's worth checking before you plan around it. For context, Sourdough Bread measures 1 mg per 1 slice, rated Safe.