How Much Oxalate Is in Sourdough Bread?
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 oxalate per 100g matter?
The per-100g number lets you compare foods on an equal-weight basis, regardless of serving size. It's useful when two foods have very different typical serving sizes, or when you eat more or less than a standard serving. Sourdough Bread comes in at 1 mg oxalate per 1 slice (Safe) in the measured database.
How accurate is the oxalate measurement?
Harvard's 2024 analysis used ion chromatography — the gold standard for oxalate measurement. These are direct lab values, not estimates or database calculations. Variability exists between samples, but this is the most reliable reference available. For context, Sourdough Bread measures 1 mg per 1 slice, rated Safe.
How does this compare to other foods?
The ratings split at 25 mg (Safe) and 100 mg (Avoid), with 25-99 mg in the Caution band. For context against similar foods, the category pages on OxalateWatch rank every item in that group by oxalate. Applied to Sourdough Bread: 1 mg oxalate per 1 slice — Safe per Harvard (2024).