Is Spinach High in Oxalates? Answering Your Top Questions

According to the National Kidney Foundation, calcium oxalate stones are the most common type of kidney stone. This is why the question of 'is spinach high in oxalates' is so important for many health-conscious individuals, particularly those at risk of kidney stones. It's a key consideration when balancing the nutritional benefits of this leafy green with potential health concerns.

Quick Summary

Spinach is notably high in oxalates, natural compounds that can affect mineral absorption and contribute to kidney stone formation in susceptible individuals. However, the antinutrient effect can be mitigated through proper cooking methods and pairing with calcium-rich foods. For most healthy people, moderate consumption is not a concern, though those prone to kidney stones should be cautious.

Key Points

• Spinach has high oxalate levels: Raw spinach is considered one of the highest-oxalate foods, which is a concern primarily for individuals susceptible to calcium oxalate kidney stones.

• Oxalates reduce mineral absorption: These compounds can bind to minerals like calcium and iron in the gut, hindering the body's ability to absorb them.

• Proper cooking lowers oxalate content: Boiling or blanching spinach is a highly effective way to reduce its soluble oxalate content by leaching the compounds into the cooking water.

• Pairing with calcium helps: Eating spinach alongside calcium-rich foods encourages oxalate to bind to calcium in the digestive tract, preventing it from being absorbed and forming kidney stones.

• Health benefits often outweigh risks: For most people, the significant nutrient content of spinach, including vitamins A, C, and K, outweighs the risks associated with oxalates.

• Individual risk is key: The need to manage oxalate intake is highly dependent on an individual's health status, especially for those with a history of kidney stones.

Understanding Oxalates: What Are They and Why Do They Matter?

Oxalates, or oxalic acid, are naturally occurring compounds found in many plants, including fruits, vegetables, nuts, and grains. They serve various functions for the plant, such as defense mechanisms and regulating mineral levels. For humans, oxalates are considered an 'antinutrient' because they can bind with essential minerals, primarily calcium, in the digestive tract. This binding can reduce the absorption of these minerals by the body.

The impact of oxalates on human health depends largely on an individual's susceptibility. For most healthy people, oxalates are harmless and are simply passed out of the body through waste. However, for individuals with a history of calcium oxalate kidney stones, a high-oxalate diet can increase the risk of recurrence. The oxalates that are not excreted can accumulate in the kidneys, forming crystals when they bind with calcium.

Is Spinach High in Oxalates? The Definitive Answer

Yes, spinach is indisputably one of the highest-oxalate foods available. Studies have shown that a 100-gram serving of raw spinach can contain anywhere from 647 to over 1200 milligrams of oxalate. To put this into perspective, many low-oxalate diets recommend limiting intake to less than 40–50 milligrams per day. This high concentration is the primary reason for concern among those monitoring their oxalate intake.

While this may sound alarming, it is crucial to remember that spinach is also packed with nutrients like vitamins A, C, and K, as well as magnesium and iron. For the majority of people, these nutritional benefits outweigh the oxalate content, provided the spinach is consumed as part of a balanced diet.

Managing Oxalate Content in Spinach

For those who are at risk of kidney stones or simply want to reduce their oxalate intake, there are effective strategies for preparing spinach to significantly lower its oxalate content. The key is to reduce the amount of soluble oxalates, which are more readily absorbed by the body.

Practical Cooking Methods

• Boiling: This is the most effective method for reducing soluble oxalates. Studies have shown that boiling spinach can remove between 30% and 87% of its oxalate content. The process leaches the soluble oxalates into the cooking water, so it is essential to discard the water afterward.
• Blanching: Similar to boiling, blanching involves a brief immersion in boiling water followed by an ice bath. This process also helps to leach out a substantial amount of oxalates and is often used to preserve the spinach's bright green color.
• Steaming: While less effective than boiling, steaming can still reduce oxalate levels, though to a lesser degree.

Pairing Spinach with Calcium-Rich Foods

Another smart strategy is to combine high-oxalate foods with calcium-rich foods during the same meal. When consumed together, calcium and oxalate are more likely to bind to each other in the digestive system, forming a compound that is then passed out of the body. This prevents the oxalate from reaching the kidneys and forming crystals. Examples include:

• Adding spinach to a salad with cheese or yogurt-based dressing.
• Serving creamed spinach alongside a meal.
• Drinking a glass of milk with your spinach-containing dish.

Comparison of High vs. Low Oxalate Foods

Category	High Oxalate Examples	Low Oxalate Alternatives
Leafy Greens	Spinach, Rhubarb, Swiss Chard, Beet Greens	Broccoli, Cabbage, Lettuce, Cauliflower, Asparagus
Nuts & Seeds	Almonds, Cashews, Peanuts, Tahini	Pine nuts, Flax seeds, Coconut
Fruits	Raspberries, Kiwis, Dates, Oranges	Bananas, Apples, Melons, Cherries, Peaches
Legumes	White Beans, Refried Beans, Soy Products	Green Peas, Lima Beans, Lentils
Grains	Wheat bran, Buckwheat, Brown Rice	White Rice, Oats, Cornmeal

Conclusion

In summary, yes, spinach is high in oxalates, but this is not a reason for most people to avoid it altogether. For the average, healthy individual, the health benefits of this nutrient-dense vegetable far outweigh any concerns related to its oxalate content. However, for those with a predisposition to calcium oxalate kidney stones, managing intake and employing proper cooking techniques is a smart strategy.

By boiling or blanching spinach and combining it with calcium-rich foods, individuals can significantly reduce the amount of absorbed oxalates. This allows for the continued inclusion of spinach in a healthy, balanced diet. As with any dietary concern, individuals with specific health conditions should consult a healthcare professional or registered dietitian for personalized advice.

Sources

• National Kidney Foundation. (2025). Kidney Stone Diet Plan and Prevention. [https://www.kidney.org/kidney-topics/kidney-stone-diet-plan-and-prevention]
• Healthline. (2023). Oxalate (Oxalic Acid): Good or Bad? [https://www.healthline.com/nutrition/oxalate-good-or-bad]
• University of Virginia Health System. (2022). Foods & Beverages High in Oxalates. [https://med.virginia.edu/ginutrition/wp-content/uploads/sites/199/2022/06/Oxalate-Foods-2022.pdf]
• GoodRx. (2024). High-Oxalate Foods: Are They Bad for Kidneys? [https://www.goodrx.com/well-being/diet-nutrition/high-oxalate-foods-bad-for-kidney-stone]
• Verywell Health. (2025). 11 Foods High and Low in Oxalates. [https://www.verywellhealth.com/oxalate-foods-11700422]
• Viome. (2025). To Eat, or Not to Eat Spinach - Viome. [https://www.viome.com/blog/to-eat-or-not-to-eat-spinach-that-is-the-question-with-oxalates]
• LinkedIn. (2019). How to Reduce Oxalate by Cooking. [https://www.linkedin.com/pulse/how-reduce-oxalate-cooking-meng-zhang]
• YouTube. (2022). How to get rid of 87% of oxalates in SPINACH? [https://www.youtube.com/shorts/38MAtdPa5tM]
• USDA ARS. (2017). Making Spinach with Low Oxalate Levels. [https://www.ars.usda.gov/news-events/news/research-news/2017/making-spinach-with-low-oxalate-levels/]
• Wiley Online Library. (2021). High and low oxalate content in spinach: an investigation of biochemical pathways and genetic variation. [https://onlinelibrary.wiley.com/doi/10.1002/jsfa.11419]
• National Institutes of Health (NIH). (2023). Oxalate in Foods: Extraction Conditions, Analytical Methods, Health Effects and Reduction Methods. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10486698/]
• Taylor & Francis Online. (2011). Effect of Cooking on Soluble and Insoluble Oxalate Contents of Some Selected Vegetables and Beans. [https://www.tandfonline.com/doi/full/10.1080/10942910903326056]
• Verywell Health. (2025). 11 Foods High and Low in Oxalates. [https://www.verywellhealth.com/oxalate-foods-11700422]
• Healthline. (2020). Low Oxalate Diet: Overview, Food Lists, and How It Works. [https://www.healthline.com/nutrition/low-oxalate-diet]
• Verywell Health. (2025). Foods to Eat and Avoid on a Low-Oxalate Diet. [https://www.verywellhealth.com/low-oxalate-diet-8770272]
• St. Joseph's Healthcare Hamilton. (2022). Oxalate in Food. [https://www.stjoes.ca/patients-visitors/patient-education/patient-education-k-o/pd-9447-oxalate-in-food.pdf]
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Frequently Asked Questions

Does boiling spinach remove oxalates?

Yes, boiling is one of the most effective methods for reducing the soluble oxalate content in spinach. A significant amount leaches into the cooking water, which should be discarded afterward.

Is raw spinach safe to eat?

For most healthy people, raw spinach is safe to eat in moderation as part of a balanced diet. Its high nutrient content offers many health benefits. However, individuals prone to kidney stones should be cautious with high consumption of raw spinach.

How does oxalate in spinach affect calcium absorption?

The oxalates in spinach can bind to calcium in the digestive system, forming insoluble calcium oxalate. This process can reduce the amount of calcium that is absorbed by the body.

What foods can I eat to counteract the oxalates in spinach?

Pairing spinach with calcium-rich foods like cheese, yogurt, or milk can help. The calcium binds to the oxalate in your gut before it can be absorbed, allowing it to pass harmlessly through your body.

Are there low-oxalate alternatives to spinach?

Yes, several leafy greens have much lower oxalate levels, including lettuce, cabbage, and broccoli. Other options for greens include mustard greens or bok choy.

How much oxalate is in spinach?

The oxalate content in spinach can vary based on the variety and how it's prepared. Raw spinach is very high, with some sources reporting over 750 mg of oxalate per 100 grams.

Should I avoid spinach if I have a history of kidney stones?

It is best to consult a healthcare provider for personalized dietary advice. While you may not need to eliminate it completely, it is often recommended to limit high-oxalate foods and use preparation methods like boiling to reduce the content.