Is Fish and Seafood Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 4 oz (113 g)
Verdict: 🟢 Safe
Per 100g: 3 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Fish and Seafood: Safe (🟢), with 3 mg oxalate per serving — comfortably below the 25 mg safe cutoff. There's no need to limit it. Just keep your usual kidney stone basics in place: water throughout the day and calcium-rich foods at meals.
Putting Fish and Seafood in context: it lands well above the category average of 2 mg. In the database, 100% of seafood (55 of 55) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical seafood here averages 2 mg oxalate per serving, so Fish and Seafood runs 94% above that baseline. That places it on the higher end for oxalate 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 seafood rated Safe for a full side-by-side.
Why does the safe threshold matter?
The 25 mg line is the reference point clinicians use to separate everyday foods from ones that need caution. Every value on this page traces back to Harvard's 2024 lab analysis, so the threshold is applied to measured data rather than estimates. For context, Fish and Seafood measures 3 mg per 4 oz, rated Safe.
Can I eat this food every day?
Daily eating is fine for Safe foods (under 25 mg/serving). For Caution or Avoid foods, spread them out and alternate with low-oxalate picks. The idea is keeping your weekly oxalate load manageable, not eliminating any single food. For context, Fish and Seafood measures 3 mg per 4 oz, 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 Fish and Seafood: 3 mg oxalate per 4 oz — Safe per Harvard (2024).
Should I also check sodium and calcium?
Yes — kidney stone risk isn't just about oxalate. High sodium increases urinary calcium (a stone promoter). Adequate dietary calcium (from food, not supplements) actually binds oxalate in your gut. Check the food's full nutrition page for the complete picture. For Fish and Seafood, the measured oxalate value is 3 mg per 4 oz (Safe).