Oxalate Food Checker
Search 70+ foods to find their oxalate content. Essential for anyone managing kidney stones, vulvodynia, or following a low-oxalate diet.
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What Are Oxalates and Why Do They Matter?
Oxalates are naturally occurring compounds found in many plant foods. Your body also produces them as a metabolic byproduct. For most people, oxalates are absorbed and excreted harmlessly through urine. But for some — particularly those prone to calcium oxalate kidney stones (the most common type) — too much dietary oxalate raises the risk of crystal formation in the kidneys.
Conditions that benefit from a low-oxalate diet include: recurrent calcium oxalate kidney stones, hyperoxaluria (excess oxalate in urine), vulvodynia (some research links oxalate sensitivity to vulvar pain), and in some cases, autism spectrum conditions and gut absorption disorders like Crohn's disease or short bowel syndrome.
Oxalate Content Reference Guide
| Level | Oxalate per 100g | Approach |
|---|---|---|
| Very High | >100mg | Avoid or eliminate |
| High | 50–100mg | Significant limit |
| Medium | 10–50mg | Moderate portions |
| Low | <10mg | Generally safe |
The Calcium Connection — Why Dairy Might Actually Help
Counterintuitively, eating calcium with high-oxalate foods reduces how much oxalate your body absorbs. Calcium binds oxalate in the gut, forming calcium oxalate complexes that pass through without being absorbed. This is why low-calcium diets can actually increase kidney stone risk in stone-prone individuals — the oxalate that would have been bound by calcium gets absorbed instead.
Practical tip: if you do eat a moderate-oxalate meal, have a dairy food alongside it. A glass of milk, some yogurt, or cheese with your meal binds oxalate before it can be absorbed.
Cooking to Reduce Oxalates
Boiling high-oxalate vegetables and discarding the cooking water removes a significant portion of their oxalate content — sometimes 30–50% for soluble oxalates. Steaming is less effective. This means boiled spinach has less oxalate than raw spinach, though both are still high. For most low-oxalate dieters, simply avoiding the high-oxalate foods is more practical than cooking them down.
💧 Hydration is the #1 intervention for kidney stone prevention. Drinking enough water (aim for urine that's pale yellow, roughly 2–2.5 litres of water daily) dilutes urine and reduces crystal formation risk — even more than dietary oxalate restriction alone. If you have a history of kidney stones, talk to your urologist before making major dietary changes.
Frequently Asked Questions
How common are kidney stones?
Very common — affecting roughly 10–15% of people in developed countries at some point in their life, with rates rising. Calcium oxalate stones account for about 80% of kidney stones. Men are more affected than women, though the gap has been narrowing.
Should I completely avoid spinach and almonds?
If you have a history of calcium oxalate kidney stones or confirmed hyperoxaluria, yes — these are significant contributors. For people without a diagnosed issue, enjoying them occasionally in the context of adequate hydration and calcium intake is generally fine. The risk comes from habitual high intake.
Is vitamin C a problem?
High-dose vitamin C supplements (over 1,000mg/day) can increase urinary oxalate because the body converts ascorbic acid to oxalate. Vitamin C from food is unlikely to be a problem at normal amounts. If you supplement vitamin C and have a history of kidney stones, talk to your doctor.
Can I eat almonds if I take calcium supplements?
Calcium supplements taken with meals bind oxalate the same way dietary calcium does — but timing matters enormously. Take calcium supplements WITH meals to get the binding effect. Taking them between meals doesn't help with oxalate absorption and may slightly raise stone risk in some people. Food-based calcium is preferable.
Is a low-oxalate diet the same as a kidney stone diet?
Not exactly. Kidney stone prevention involves multiple factors: oxalate reduction, adequate calcium intake, very high hydration, reducing sodium (which increases calcium in urine), limiting animal protein (which raises urinary acidity), and sometimes limiting purine-rich foods. Oxalate restriction is one part of the picture, not the whole strategy.
How strict does the diet need to be?
It depends on your reason for following it. For kidney stone prevention, research suggests reducing the highest oxalate foods (very high category: spinach, almonds, rhubarb, wheat bran, chocolate in large amounts) makes the most meaningful difference. You don't need to eliminate every moderate-oxalate food. For hyperoxaluria or specific medical conditions, stricter guidance from a nephrologist or renal dietitian is appropriate.