Is Spinach frozen Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1/2 cup (95 g)
Verdict: 🟢 Safe
Per 100g: 3.2 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Spinach frozen: 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 Spinach frozen in context: it lands well below the category average of 27 mg. In the database, 80% of vegetables (219 of 271) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical vegetables here averages 27 mg oxalate per serving, so Spinach frozen runs 89% 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 vegetables 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 Spinach frozen, the measured oxalate value is 3 mg per 1/2 cup (Safe).
Can I eat this food every day?
For Safe foods (under 25 mg/serving), daily use is generally fine. Caution and Avoid foods work better as occasional items — rotate them with safer options so no single high-oxalate food becomes a habit. For Spinach frozen, the measured oxalate value is 3 mg per 1/2 cup (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. For context, Spinach frozen measures 3 mg per 1/2 cup, rated Safe.
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. Applied to Spinach frozen: 3 mg oxalate per 1/2 cup — Safe per Harvard (2024).