High-Oxalate Foods: The Complete List

The very high-oxalate foods

The foods that dominate urinary oxalate: rhubarb (~1,000 mg/100g), spinach (~750 mg), Swiss chard (~645 mg), and beet greens (~610 mg). A single serving of spinach — a smoothie, a curry, a salad — can double daily oxalate intake. For oxalate stone formers, these are the foods to genuinely limit.

Preparation note: boiling reduces oxalate somewhat (it leaches into the water — discard the water); steaming and sautéing less so. But even boiled spinach stays high.

High and moderate sources

High: beets (200-700 mg), almonds (~470 mg), okra (~150 mg), sweet potato (~110-160 mg), chocolate/cocoa (~300-600 mg), peanuts and peanut butter (~90-190 mg), sesame seeds, amaranth, sorrel, purslane.

Moderate: black tea (a few mg per cup, more with heavy steeping), strawberries, raspberries, wheat bran, soy products, and many beans. Black tea plus high-oxalate meals can tip urine oxalate up.

Notable 'hidden' sources: star fruit (carambola) is extremely high in oxalate and can cause acute kidney injury even in normal people — avoid entirely.

Who actually needs to limit oxalate

Not every stone former. The decision should follow the 24-hour urine oxalate result: if urine oxalate is under 40 mg/day, modest oxalate intake is usually fine; if elevated, limit the very high sources and pair them with calcium.

Practical rules for oxalate stone formers: keep spinach/rhubarb/beets to occasional servings, don't drink concentrated tea with meals, avoid vitamin C supplements above 200 mg/day (ascorbic acid converts to oxalate), and eat high-oxalate foods with dairy.