What You Need to Know About Oxalates

Eating a spinach salad or a handful of raw almonds sounds perfectly healthy. But for some people, these foods can pose unexpected problems. The culprit? Oxalates, which you’ll find in many plant foods. These compounds protect plants by deterring animals, safeguarding against other harmful organisms, and regulating calcium levels within plant cells.¹ 

In humans, oxalates aren’t so beneficial. They bind to calcium, zinc, and magnesium in your digestive tract, making it harder for your body to absorb these essential minerals. Scientists call oxalates “anti-nutrients” because they hinder the absorption of crucial nutrients.² 

High oxalate intake can worsen symptoms and lead to nutrient deficiencies for some people. However, they aren’t a problem for everyone. 

How Oxalates Impact Your Body

Oxalates in humans come from two primary sources: dietary intake and internal production. Approximately half of the oxalates in your body come directly from the foods you eat.³ The rest are produced internally, as your body converts substances like vitamin C into oxalates during metabolism.⁴

Several other factors influence your body’s oxalate production, including:

• Gut health: Healthy gut bacteria can break down oxalates, preventing their absorption and reducing the risk of kidney stones.⁵ 
• Protein intake: High protein consumption can lead to increased oxalate levels because amino-acid breakdown during digestion raises oxalate production. However, for most people, a healthy gut can manage a high-protein diet without issue.⁶
• Salt and sugar: Excessive salt intake increases calcium excretion in urine, which can then combine with oxalate to form stones.⁷ High sugar intake, particularly from fructose, can also elevate oxalate production.⁸

For healthy individuals, the digestive tract binds oxalates with minerals like calcium, zinc, and magnesium, forming crystals. The kidneys then filter these crystals from the blood and expel them through urine, maintaining mineral balance and supporting waste elimination.⁹

However, excessive oxalates can cause problems for some people by forming crystals in urine. When oxalates bind with calcium in your kidneys, they can create calcium oxalate stones, the most common type of kidney stone. These stones develop if you consume many oxalate-rich foods and your body can’t eliminate the excess.¹⁰

Oxalate Content in Foods

Many vegetables, fruits, nuts, and other plant foods contain oxalates. Some, however, have high levels of these compounds. Spinach is among the highest, with up to 755mg of oxalates in just 1/2 cup of cooked spinach. Other foods high in oxalates include:

• Beets: 1 cup of beets has about 152mg.
• Potatoes: A medium-sized baked potato has about 97 mg.
• Legumes: Navy beans are the highest, with 76mg per 1/2 cup.
• Raspberries: 1 cup has about 48 mg.
• Almonds: 22 nuts contain roughly 122 mg.¹¹

Eating these and other high-oxalate foods in large amounts can increase the risk of oxalate-related health issues, especially if you are prone to kidney stones or have oxalate sensitivities.¹² 

Identifying Oxalate Sensitivity

Oxalate sensitivity refers to an adverse reaction to foods high in oxalates. For susceptible people, consuming high-oxalate foods can lead to health issues such as kidney stones, joint pain, and chronic inflammation. This sensitivity is often due to an inability to properly metabolize oxalates, influenced by factors like gut health and genetic predisposition.¹³ 

Several risk factors can boost the likelihood of experiencing health issues related to oxalates:

• Hyperoxaluria: A metabolic disorder characterized by high levels of oxalates in your urine, which can be either primary (inherited) or secondary (acquired).¹⁴ 
• Gut health issues: Poor gut health or conditions like leaky gut syndrome can increase oxalate absorption, leading to higher levels in your body.¹⁵ 
• Diet: Consuming a diet high in oxalates or certain foods that promote oxalate production can elevate your risk. The risk is higher for:
  • Individuals prone to kidney stones: Those with a history of kidney stones are more likely to develop new stones if they consume high-oxalate foods.¹⁶ 
  • People with certain health conditions, such as hyperoxaluria or gut disorders, can increase oxalate absorption and risk.¹⁷
  • Those with poor hydration: Not drinking enough water can make it harder for the body to flush out oxalates, increasing the likelihood of kidney stone formation.¹⁸ 
  • People with metabolic disorders: Disorders like hyperoxaluria can affect how the body processes and eliminates oxalates, raising the risk of related health problems.¹⁹ 

Managing oxalate sensitivity requires dietary modifications. This includes reducing or avoiding high-oxalate foods, increasing water intake to help flush oxalates from the body, and ensuring optimal calcium intake, which can help bind oxalates in the gut and prevent their absorption.

Work with a functional medicine nutritionist or doctor if you’re considering a low-oxalate diet. Oxalate dumping can occur when the body releases stored oxalates into the bloodstream for excretion. This can happen after reducing oxalate intake, leading to symptoms like pain, urinary issues, and digestive problems as the body processes and eliminates oxalates.²⁰  

A professional can guide you safely in gradually lowering your oxalate consumption, ensuring you maintain proper nutrient intake and avoid adverse effects. They can also help monitor your health and adjust your diet to support overall well-being while managing your oxalate levels.

Managing Your Oxalate Intake

Oxalates aren’t an issue for most people, but it’s wise to monitor your intake to reduce the risk of health issues, particularly kidney stones. 

Many foods on The Virgin Diet, such as asparagus, Brussels sprouts, broccoli, and freshly ground flaxseed, are low in oxalates. Following The Virgin Diet can also help fix leaky gut, improving your gut lining and reducing oxalate absorption into the bloodstream. A healthier gut barrier prevents excess oxalates from entering the body, lowering your risk of kidney stones and other related health issues. 

You can also make simple swaps, like using Swiss chard or kale instead of spinach, strawberries instead of blueberries, and fresh coconut instead of grapes. This database lists over 750 foods to determine their oxalate content. One way to manage oxalate intake is to balance high-oxalate foods like spinach and almonds with low-oxalate alternatives like kale and strawberries. Here are five more ways to manage oxalate intake.

1. Prepare Your Food Smartly

Food preparation techniques can significantly reduce oxalate levels in your diet. 

Boiling vegetables can reduce their oxalate content by up to 87%.²¹  Chop the vegetables into small pieces, cook them in plenty of water, and discard the water afterward.

Steaming can reduce oxalates up to 53% and preserves more nutrients than boiling.²² Steam vegetables for at least 5-10 minutes. 

Soaking legumes can leach oxalates into water.²³ Soak foods for several hours or overnight, changing the water midway.

2. Eat Calcium-Rich Foods

To help prevent oxalate absorption, eat calcium-rich foods with higher-oxalate foods. Calcium binds with oxalates in your digestive system, reducing the risk of kidney stones.²⁴  Good sources of calcium include:

• Leafy greens: Kale, broccoli, and bok choy.
• Dairy products: Greek-style yogurt preferred, as long as you’re not dairy intolerant.
• Nuts and seeds: Almonds and chia seeds are especially rich in calcium. Consuming them in moderation (about an ounce daily) helps you get the calcium benefits without increasing your oxalate intake too much. 
• Fish with bones: Wild-caught sardines and salmon provide good amounts of calcium.

3. Stay Hydrated

Drinking enough water dilutes your urine, reducing oxalate concentration and preventing crystal formation.²⁵  

Lemon water especially helps because citric acid binds with calcium, making it less likely to form stones.²⁶ 

Green tea is a great option for hydration with many benefits. Among them, it contains antioxidants called catechins that inhibit oxalate crystallization, further supporting kidney health.²⁷ 

4. Get the Right Nutrients

Certain vitamins and minerals can help minimize your risk of oxalate-related issues like kidney stones. Here’s how they work and what you need to include in your diet:

• Omega-3 fatty acids: These fatty acids in wild-caught fish and fish oil have anti-inflammatory properties that support kidney health. Chronic inflammation can increase the risk of kidney stones.²⁸ 
• Vitamin B6: Vitamin B6 (pyridoxine) helps break down oxalates in the body, reducing their overall levels and the risk of kidney stone formation. It converts oxalates into less harmful substances that the body can efficiently excrete.²⁹ 
• Magnesium: This mineral binds to oxalates in your intestines, preventing their absorption into the bloodstream. This process reduces free oxalates, which can form kidney stones.³⁰ Magnesium-rich foods include leafy green vegetables, nuts, and seeds. A high-quality magnesium supplement can also help. Look for one that contains therapeutic amounts of chelated magnesium, formulated through a patented process to ensure superior absorption and bioavailability. This means your body can effectively utilize more magnesium, enhancing its benefits and reducing the digestive discomfort inferior forms can create.
• Calcium: Getting optimal amounts of this mineral can help reduce the risk of kidney stones. Calcium in the digestive tract binds with oxalates from food, forming insoluble complexes that your body excretes in your stool rather than being absorbed into the bloodstream and passing through the kidneys. This decreases the concentration of oxalates in your urine, lowering the likelihood of stone formation.³¹  Look for a calcium citrate supplement, which absorbs well and may have a modestly beneficial effect on urine pH, which can further help reduce stone formation.

5. Heal Your Gut

Maintaining a healthy gut is crucial for managing oxalates.³²  Beneficial bacteria like Oxalobacter formigenes play a key role in breaking down oxalates, reducing their absorption into the bloodstream. These bacteria consume oxalates as a nutrient source, effectively lowering the amount that can enter your body and contribute to kidney stone formation.

Fermented foods can help with oxalates by introducing beneficial bacteria that break down oxalates in the gut. Regularly eating fermented foods like Greek yogurt (if you can tolerate dairy), sauerkraut, and kimchi can support a healthy gut microbiome, enhancing your body’s ability to manage oxalates effectively. Studies show that fermented foods can also help manage inflammation that can contribute to oxalate problems.³³ 

Master Your Gut Health to Manage Oxalate Intake

Improving your gut health can significantly help manage your oxalate levels. A healthy gut fosters the growth of beneficial bacteria that break down oxalates, reducing its absorption and excretion. 

I wrote 5 Gut-Healing Strategies for Lasting Energy & Weight Loss to focus on gut health. In this short, informative guide, you’ll learn the foods and other factors that hurt your gut, get a comprehensive symptom checklist, and discover five powerful gut-healing strategies to boost your energy and support lasting weight loss.

Get your FREE 5 Gut-Healing Strategies for Lasting Energy & Weight Loss here.

References:

1. Baltazar P, de Melo Junior AF, Fonseca NM, Lança MB, Faria A, Sequeira CO, Teixeira-Santos L, Monteiro EC, Campos Pinheiro L, Calado J, Sousa C, Morello J, Pereira SA. Oxalate (dys)Metabolism: Person-to-Person Variability, Kidney and Cardiometabolic Toxicity. Genes (Basel). 2023 Aug 29;14(9):1719. doi: 10.3390/genes14091719. PMID: 37761859; PMCID: PMC10530622.
2. Colorado State University: Should I be Avoiding Oxalates?
3. Paiva ÉAS. Do calcium oxalate crystals protect against herbivory? Naturwissenschaften. 2021 May 27;108(3):24. doi: 10.1007/s00114-021-01735-z. PMID: 34043088.
4. Mitchell T, Kumar P, Reddy T, Wood KD, Knight J, Assimos DG, Holmes RP. Dietary oxalate and kidney stone formation. Am J Physiol Renal Physiol. 2019 Mar 1;316(3):F409-F413. doi: 10.1152/ajprenal.00373.2018. Epub 2018 Dec 19. PMID: 30566003; PMCID: PMC6459305.
5. ScienceDirect: A new direction in kidney stone prevention and treatment
6. Knight J, Easter LH, Neiberg R, Assimos DG, Holmes RP. Increased protein intake on controlled oxalate diets does not increase urinary oxalate excretion. Urol Res. 2009 Apr;37(2):63-8. doi: 10.1007/s00240-009-0170-z. Epub 2009 Jan 29. PMID: 19183980; PMCID: PMC2683385.Paiva ÉAS. Do calcium oxalate crystals protect against herbivory? Naturwissenschaften. 2021 May 27;108(3):24. doi: 10.1007/s00114-021-01735-z. PMID: 34043088.
7. Shah A, Leslie SW, Ramakrishnan S. Hyperoxaluria. [Updated 2024 Mar 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK558987/
8. ScienceDirect: Fructose consumption and the risk of kidney stones
9. Mitchell T, Kumar P, Reddy T, Wood KD, Knight J, Assimos DG, Holmes RP. Dietary oxalate and kidney stone formation. Am J Physiol Renal Physiol. 2019 Mar 1;316(3):F409-F413. doi: 10.1152/ajprenal.00373.2018. Epub 2018 Dec 19. PMID: 30566003; PMCID: PMC6459305.
10. National Kidney Foundation: Calcium oxalate stone – Causes, prevention, treatment
11. WebMD: Foods High in Oxalates
12. Mayo Clinic: Hyperoxaluria and oxalosis – Symptoms and causes
13. Healthline: Oxalate (Oxalic Acid): Good or Bad?
14. Shah A, Leslie SW, Ramakrishnan S. Hyperoxaluria. [Updated 2024 Mar 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK558987
15. Hatch M. Gut microbiota and oxalate homeostasis. Ann Transl Med. 2017 Jan;5(2):36. doi: 10.21037/atm.2016.12.70. PMID: 28217701; PMCID: PMC5300851.
16. Ferraro PM, Bargagli M, Trinchieri A, Gambaro G. Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian-Vegan Diets. Nutrients. 2020 Mar 15;12(3):779. doi: 10.3390/nu12030779. PMID: 32183500; PMCID: PMC7146511.
17. Mayo Clinic: Hyperoxaluria and oxalosis – Symptoms and causes
18. Gamage KN, Jamnadass E, Sulaiman SK, Pietropaolo A, Aboumarzouk O, Somani BK. The role of fluid intake in the prevention of kidney stone disease: A systematic review over the last two decades. Turk J Urol. 2020 Nov;46(Supp. 1):S92-S103. doi: 10.5152/tud.2020.20155. Epub 2020 Jun 5. PMID: 32525478; PMCID: PMC7731957.
19. Bhasin B, Ürekli HM, Atta MG. Primary and secondary hyperoxaluria: Understanding the enigma. World J Nephrol. 2015 May 6;4(2):235-44. doi: 10.5527/wjn.v4.i2.235. PMID: 25949937; PMCID: PMC4419133.
20. Healthline: What Is Oxalate Dumping? Symptoms, Dangers, and Treatment
21. Chai W, Liebman M. Effect of different cooking methods on vegetable oxalate content. J Agric Food Chem. 2005 Apr 20;53(8):3027-30. doi: 10.1021/jf048128d. PMID: 15826055.
22. Chai W, Liebman M. Effect of different cooking methods on vegetable oxalate content. J Agric Food Chem. 2005 Apr 20;53(8):3027-30. doi: 10.1021/jf048128d. PMID: 15826055.
23. Noonan SC, Savage GP. Oxalate content of foods and its effect on humans. Asia Pac J Clin Nutr. 1999 Mar;8(1):64-74. PMID: 24393738.
24. National Kidney Foundation: 6 Easy Ways to Prevent Kidney Stones
25. Bao Y, Tu X, Wei Q. Water for preventing urinary stones. Cochrane Database Syst Rev. 2020 Feb 11;2(2):CD004292. doi: 10.1002/14651858.CD004292.pub4. PMID: 32045491; PMCID: PMC7012319.
26. Harvard Health: How to pass a kidney stone & 5 tips to prevent them
27. Itoh Y, Yasui T, Okada A, Tozawa K, Hayashi Y, Kohri K. Preventive effects of green tea on renal stone formation and the role of oxidative stress in nephrolithiasis. J Urol. 2005 Jan;173(1):271-5. doi: 10.1097/01.ju.0000141311.51003.87. PMID: 15592095.
28. Medical News Today: Omega-3 fatty acids from fish may reduce chronic kidney problems
29. Ferraro PM, Taylor EN, Gambaro G, Curhan GC. Vitamin B6 intake and the risk of incident kidney stones. Urolithiasis. 2018 Jun;46(3):265-270. doi: 10.1007/s00240-017-0999-5. Epub 2017 Jul 3. PMID: 28674784; PMCID: PMC5752631.
30. Importance of Magnesium in Absorption and Excretion of Oxalate
31. Finkielstein VA, Goldfarb DS. Strategies for preventing calcium oxalate stones. CMAJ. 2006 May 9;174(10):1407-9. doi: 10.1503/cmaj.051517. PMID: 16682705; PMCID: PMC1455427.
32. ​​Karamad D, Khosravi-Darani K, Khaneghah AM, Miller AW. Probiotic  Oxalate-Degrading Bacteria: New Insight of Environmental Variables and Expression of the oxc and frc Genes on Oxalate Degradation Activity. Foods. 2022 Sep 16;11(18):2876. doi: 10.3390/foods11182876. PMID: 36141002; PMCID: PMC9498451.
33. Kaufman DW, Kelly JP, Curhan GC, Anderson TE, Dretler SP, Preminger GM, Cave DR. Oxalobacter formigenes may reduce the risk of calcium oxalate kidney stones. J Am Soc Nephrol. 2008 Jun;19(6):1197-203. doi: 10.1681/ASN.2007101058. Epub 2008 Mar 5. PMID: 18322162; PMCID: PMC2396938.
34. Stanford Medicine: Fermented-food diet increases microbiome diversity, decreases inflammatory proteins, study finds

*These statements have not been evaluated by the Food & Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease. The views in this blog by JJ Virgin should never be used as a substitute for professional medical advice. Please work with a healthcare practitioner concerning any medical problem or concern.