Dietary Oxalates: A Patient Guide for Adults

Dietary oxalates (sometimes called “oxalic acid”) are natural compounds found in many plant foods. For most people, oxalates are not harmful. However, in some individuals—especially those with a history of kidney stones, certain gastrointestinal conditions, or specific metabolic issues—eating too many high-oxalate foods may increase stone risk or digestive discomfort.

This guide explains what oxalates are, how they affect health, and which foods are higher or lower in oxalates.

What Are Oxalates?

Oxalates are substances that occur naturally in many vegetables, fruits, nuts, grains, and legumes. When oxalates combine with calcium in the kidneys, they can form calcium oxalate crystals—the most common type of kidney stone.

Not everyone needs to reduce oxalates. However, older adults and people with kidney issues, bowel disorders, or repeated kidney stones may be encouraged by their providers to monitor their intake.

Who Might Need to Watch Their Oxalate Intake?

Your healthcare provider may discuss oxalates with you if you have:

A history of calcium oxalate kidney stones
Chronic diarrhea, malabsorption, or bowel disease (Crohn’s disease, ulcerative colitis, celiac disease, short-gut syndrome)
Bariatric surgery history
Impaired kidney function
Conditions requiring calcium or vitamin D balance support

Always follow the guidance of your provider or renal dietitian.

General Tips for Managing Oxalates

Pair calcium-rich foods with meals (calcium binds oxalates in the gut before they reach the kidneys).
Drink plenty of water daily to help flush the kidneys.
Spread high-oxalate foods throughout the week instead of eating them at one meal.
Avoid very high-oxalate foods if you have known kidney stone issues (only if directed by your provider).
Focus on moderation — not complete avoidance.
Remember: oxalate content varies widely depending on soil, variety, and preparation – ask your healthcare provider for recommendations tailored to you.

Foods High, Moderate, and Low in Oxalates

Below is a categorized list to help guide food choices. Amounts may vary depending on preparation.

Oxalate Serving Categories (according to Urology Group of Virginia):

Low oxalate: ~ 10 mg or less per typical serving
Moderate oxalate: ~ 11–29 mg per serving
High oxalate: ~ 30 mg or more per serving

Oxalate Level	Examples of Foods / Food Groups
🔴 High-Oxalate Foods (Limit or avoid if you have kidney stones or high urine oxalate)	- Spinach (raw or cooked) - Almonds (¼ cup) - Beets & beet greens / beets root - Rhubarb - Wheat-bran or high-bran cereals / products (e.g. bran cereal, bran breads) - Buckwheat, bulgur, other high-bran grains / certain grains with high oxalate load - Tofu & some soy products (depending on serving) - Nuts & seeds (especially almonds, cashews)
🟡 Moderate-Oxalate Foods (Use with caution — especially if forming stones)	- Brown rice (½ cup cooked) - Whole-wheat products / whole-wheat bread (some servings labeled “moderate” vs. high) - Some cereals & grain-based foods (e.g. items with modest oxalate values) - Legumes/beans in some cases (depending on preparation and oxalate load — caution advised) - Mixed nuts / seed mixes if portion is small and intake moderated
🟢 Low-Oxalate Foods (Preferred / Generally Safer for Stone Risk)	- Most dairy and animal proteins — e.g. milk, cheese, eggs, most meat/fish/chicken — oxalate content is negligible or very low according to Urology Group list. - Plain white rice, plain pasta, many refined grain products without bran - Many non-leafy vegetables that are not on high-oxalate lists (e.g. certain non-green, non-leafy vegetables) — because oxalate is primarily in high-oxalate greens and certain plant foods - Water and plenty of fluids — important for kidney stone prevention

Go to: https://www.urologygroupvirginia.com/content/kidney-stone-center/7-oxalate-and-kidney-stones/oxalate-food-list-summer-2020_3-7-1.pdf to see the full list.

Additional Tips for Reducing Stone Risk

These apply to most older adults with kidney stone concerns:

Drink 64–80 oz of fluid per day unless restricted by your provider.
Eat foods naturally rich in calcium (don’t avoid calcium; low calcium increases oxalate absorption).
Limit excess sodium, which increases calcium in the urine.
Avoid large doses of vitamin C supplements, which can convert to oxalate in the body.
Maintain regular meals — skipping meals may increase stone-forming risk.

📌 When to Contact Your Healthcare Provider

Speak with your care team if you experience:

Flank or back pain
Blood in urine
Frequent stone formation
Trouble staying hydrated
Unexplained nausea or urinary symptoms
Always ask your healthcare provider for specific advice on when to call to report symptoms, and when to seek urgent/emergency care.

Your provider can recommend whether oxalate reduction is needed and tailor your diet based on your medical conditions and medications.

⚠️ Medical Disclaimer

The dietary information provided in this resource is for general educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Individual nutrition needs vary based on medical history, medications, allergies, and overall health status.

Before making any changes to your diet, trying new foods, modifying portion sizes or fluid intake, or following any nutrition recommendations, please consult your physician, registered dietitian, or other qualified healthcare provider. If you have diabetes, kidney disease, gastrointestinal conditions, food intolerances, or other chronic health concerns, discussing dietary changes with your healthcare team is especially important.

This handout is for educational purposes only and is not a substitute for professional medical advice. Always follow your healthcare provider’s instructions.