Is Spinach High in Oxalates?

If you’re wondering “is spinach high in oxalates,” here’s the short answer.

Spinach contains about 755mg of oxalates per 1/2 cup cooked (90g). That is considered very high compared to other foods. Spinach is the single highest-oxalate food most people eat. One half-cup of cooked spinach contains about 755mg of oxalates, more than 7 times the recommended daily limit of 100mg.

To put that in perspective, most kidney stone dietitians recommend staying under 100mg of oxalates per day. A single serving of spinach uses 755% of that budget.

How Does This Compare?

Among leafy greens, spinach is far ahead of everything else. Kale has about 17mg per cup, romaine has near zero, and arugula sits around 15mg per cup raw.

Who Should Watch Their Intake?

Anyone with a history of calcium oxalate kidney stones should avoid spinach. Even for people without kidney issues, one serving blows past the entire daily oxalate budget.

Lower-Oxalate Alternatives

  • Kale (17mg/cup)
  • Romaine lettuce (<1mg/cup)
  • Arugula (15mg/cup raw)
  • Iceberg lettuce (<1mg/cup)

What Are Oxalates?

Oxalates (oxalic acid) are natural compounds found in many plants. Your body also produces them as a metabolic byproduct. In small amounts, they pass through your system without issues.

The problem starts when oxalate intake is high and calcium intake is low. Oxalates bind to calcium in the kidneys and form calcium oxalate crystals, the most common type of kidney stone. About 80% of kidney stones are calcium oxalate.

How to Reduce Oxalate Absorption

  • Pair high-oxalate foods with calcium. Eating calcium-rich foods (like cheese or yogurt) at the same meal binds oxalates in the gut before they reach the kidneys.
  • Cook your vegetables. Boiling reduces oxalate content by 30-50% because oxalates leach into the water. Steaming helps less.
  • Drink plenty of water. Staying hydrated dilutes oxalate concentration in urine, reducing crystal formation.
  • Spread intake across meals. A moderate-oxalate food at each meal is better than a high-oxalate food all at once.

The Bottom Line

Spinach is very high in oxalates. If you have a history of kidney stones or are on a low-oxalate diet, limit or avoid it. There are good alternatives that give you similar nutrition without the oxalate load.

Want Help Building a Diet That Works for You?

Tracking oxalates is just one piece of the puzzle. A health coach can help you build a whole-food eating plan that accounts for oxalates, inflammation, gut health, and your personal goals. Book a free discovery call to get started.

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Disclaimer: Oxalate values are approximate and based on Harvard T.H. Chan School of Public Health. Values can vary by growing conditions, preparation method, and brand. This content is for informational purposes only and does not constitute medical advice. Consult a healthcare provider or registered dietitian for personalized guidance. Last verified March 2026.