Holy Kale!
Diet and Kidney Stones
Kale is the vegetable everyone in the health world loves. Kale salad, kale chips, kale tonic, kale powder. It's low in calories, has zero fat, is high in fiber, and is packed with copper, calcium, potassium, iron, magnesium, omega-3s and more. So it's the perfect food for everyone, right? Not if you're someone who gets kidney stones.
General figures; individual results vary.
The Catch
Why kale and kidney stones don't mix
Kale is high in oxalates, natural compounds found in a wide range of foods that play a supportive role in your metabolism. For most people that's no problem. But if you form stones easily, or you don't drink enough during the day, high oxalate in your urine is the perfect setup for a calcium oxalate stone: the oxalate binds to calcium, crystals form, and over time those crystals become a stone.
Kale isn't alone. Beets, spinach, dark chocolate, sweet potatoes, tea and okra sit in the same high-oxalate group. Our guide to which oxalates actually matter ranks the whole list, because the gap between the worst offenders and foods that merely get labeled "high" is enormous.
The Fix
How to keep kale on the menu
You don't have to give it up. You have to be smart about it.
The bottom line
1Cook it.
2Pair it with calcium.
3Flush it with water and citrate.
Cook it
Boiling greens cuts their oxalate content by roughly half, because oxalate leaches into the water. Steaming helps less, raw helps not at all. If you love kale salad, make it the occasional one and let sautéed or boiled kale be the regular.
Pair it with calcium
Eat kale with a calcium source at the same meal, like cheese, yogurt or milk. The calcium binds to oxalate in your gut before it's absorbed, so less of it ever reaches your kidneys. The timing matters: a calcium supplement taken at a different time of day doesn't do the same job.
Flush it with water and citrate
Whatever oxalate does get through, dilute urine gives it fewer chances to meet calcium and crystallize. Drink plenty of water after a high-oxalate meal, and add KSPtabs so the citrate is in your urine binding calcium before the oxalate can.
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Enjoy the kale. Give your kidneys backup.
KSPtabs was developed by a board-certified urologist for exactly this problem. Drop one in your water and the citrate gets to work binding calcium in your urine before oxalate can. Magnesium and vitamin B6 help keep oxalate in check, and balanced sodium and potassium help your body hold onto the water you drink, so the water you drink does its job.
- ✓Drop one tablet in water, let it fizz, drink
- ✓Citrate + electrolytes to support healthy urinary citrate levels
- ✓33% increase in urinary citrate in a small clinical study*
*Median urinary citrate increased 33% during KSPtabs use. Small study in 10 healthy adults with no history of kidney stones; the study evaluated urine chemistry and did not assess kidney stone recurrence. Journal of Urology, 2021. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Common Questions
Kale and kidney stone FAQ
Can I eat kale if I get kidney stones?
In most cases, yes, in sensible portions. Cook it, eat it with a calcium source like cheese or yogurt, and follow it with plenty of water and citrate. Complete avoidance is only recommended for a small group of people with hyperoxaluria under a doctor's care.
Does cooking kale reduce oxalate?
Yes. Boiling cuts oxalate by roughly half because it leaches into the cooking water, which you then pour off. Steaming reduces it a little; raw kale keeps all of it. Kale chips and kale powder are concentrated, so treat those as the highest-oxalate form.
What other healthy foods are high in oxalate?
Spinach, beets, okra, almonds and other nuts, dark chocolate and tea are the ones that move the needle most. Foods like blueberries and celery get the "high oxalate" label but sit nowhere near that group. The oxalate guide breaks it into tiers so you know what to limit and what to stop worrying about.
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This article is for general information and isn't a substitute for medical advice. Talk with your doctor about your specific kidney stone risk and diet.
