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🟢 Tomato Paste VS 🔴 Spinach, fresh or frozen

The oxalate gap between these two is hard to ignore. Spinach, fresh or frozen at 493 mg per serving vs Tomato Paste at 3 mg — 164x more. One is a daily option, the other requires careful consideration.

✓ Medically Reviewed Content reviewed by OxalateWatch editorial team. Based on Harvard T.H. Chan SPH oxalate data (2024) and NKF/AUA dietary guidelines.

⚖️ Head-to-Head Comparison

🟢
Tomato Paste
Safe — Low Oxalate
3 mg oxalate / serving
Serving: 1 tbsp (16 g)
Per 100 g: 19 mg oxalate
Sodium: 61 mg/100g | Calcium: 36 mg/100g | Protein: 4.2 g/100g
🔴
Spinach, fresh or frozen
Avoid — Very High Oxalate
493 mg oxalate / serving
Serving: 1/2 cup (87 g)
Per 100 g: 567 mg oxalate
Sodium: 111 mg/100g | Calcium: 68 mg/100g | Protein: 2.9 g/100g

🏆 The Verdict: Choose Tomato Paste

At 3 mg oxalate per serving (rated Safe), Tomato Paste is the clear winner over Spinach, fresh or frozen (493 mg, Avoid). The 164x difference comes from Harvard's 2024 lab measurements — this isn't an estimate or guess. Build your meals around Tomato Paste and use Spinach, fresh or frozen sparingly, if at all.

🔍 Key Takeaways

**Oxalate gap:** 493 mg vs 3 mg per serving — a 164x difference. One of these is significantly easier to fit into a kidney stone diet.
**Verdicts:** Spinach, fresh or frozen is rated **Avoid (100+ mg/serving)**; Tomato Paste is rated **Safe (under 25 mg/serving)**.
**Serving strategy:** If you choose Spinach, fresh or frozen, consider a half portion or pair it with a calcium source. Tomato Paste can be eaten more freely.
**Cooking tip:** For either vegetable, boiling and discarding the cooking water can reduce soluble oxalate by 30-50%. Steaming or eating raw preserves more oxalate.

❓ Frequently Asked Questions

Which is better for kidney stones — Spinach, fresh or frozen or Tomato Paste?

Straight answer: Tomato Paste. With 3 mg oxalate per serving (Safe), it's significantly safer than Spinach, fresh or frozen (493 mg, Avoid). The 164x gap is measured by Harvard's 2024 lab analysis, not estimates. Pick Tomato Paste for daily eating, save Spinach, fresh or frozen for occasional use.

Can I eat Spinach, fresh or frozen and Tomato Paste together?

Yes, but watch your portions. Combined, you're looking at roughly 496 mg oxalate. If one is high-oxalate, keep it to a small side portion. The lower-oxalate food can fill most of your plate.

How should I prepare Spinach, fresh or frozen vs Tomato Paste differently?

Key difference: Spinach, fresh or frozen benefits significantly from boiling (discard the water!) — that can reduce oxalate by 30-50%. Tomato Paste doesn't need special prep since its oxalate is already low. Roasting, steaming, or eating raw are all fine for the low-oxalate option.

What are good substitutes if I want to avoid Spinach, fresh or frozen?

Your best bet: Tomato Paste. It's in the same category and has dramatically less oxalate. Check the Related Foods section on Spinach, fresh or frozen's page for more specific alternatives verified by Harvard's 2024 data.

Browse all Vegetables 🟢 Low Oxalate Foods Tomato Paste page Spinach, fresh or frozen page
This is dietary reference information, NOT medical advice. Talk to your doctor or a registered dietitian before changing your diet. Oxalate tolerance varies by person, stone type, and medication.