How Much Oxalate Is in Sardines?
mg oxalate
per serving
Serving: 3 oz (85 g)
Verdict: 🟢 Safe
Per 100g: 5 mg
Data: Harvard T.H. Chan SPH (2024)
What this means: Sardines is rated Safe (🟢). At 4 mg oxalate per serving, it's well under the 25 mg safety threshold. You can include it regularly in a kidney stone diet. Pair it with calcium-rich foods (dairy, fortified plant milks) for additional protection, and drink plenty of water throughout the day.
Among seafood, Sardines sits well above the category average of 2 mg. For context, 55 out of 55 seafood (100%) are rated 🟢 Safe (under 25 mg oxalate/serving). The average seafood in our database has 2 mg oxalate per serving — which means Sardines is 158% above the category norm. Within its specific category, Sardines ranks on the higher end for oxalate. This context matters because two 'Safe' foods can have very different oxalate levels — one might have 5 mg while another has 24 mg. Both are Safe, but the first gives you more dietary flexibility. Browse all seafood rated Safe to compare within the same verdict level.
Why does oxalate per 100g matter?
Per-100g values put every food on the same scale, which is handy when serving sizes differ a lot between foods — or when your portion doesn't match the standard serving. It lets you compare apples to apples on oxalate density. Applied to Sardines: 4 mg oxalate per 3 oz — Safe per Harvard (2024).
How accurate is the oxalate measurement?
These values come from Harvard's 2024 ion-chromatography analysis — the gold-standard method for oxalate. Real measured data rather than estimates. Sample-to-sample variation exists, but no published source is more dependable for food oxalate. For context, Sardines measures 4 mg per 3 oz, rated Safe.
How does this compare to other foods?
Anything under 25 mg per serving is Safe; 25-99 mg is Caution; 100 mg or more is Avoid. The category pages on OxalateWatch list foods side by side, so you can see where this one ranks. Sardines comes in at 4 mg oxalate per 3 oz (Safe) in the measured database.