Hannah Zulueta The Greens, Sorted Twice
Potassium and oxalates in nineteen green vegetables
Green vegetables belong in most kidney bowls, but choosing them means reading two numbers at once. This is the working chart of potassium and oxalates in green vegetables for kidney diets, and the same nineteen greens tell two very different stories depending on which lens you look through.
A chart tells you which greens are high. It cannot tell you what your dog needs.
Hyperkalemia, potassium running high, is a real complication in a subset of dogs with chronic kidney disease, and it has been tied to commercial renal diets often enough that researchers corrected it with potassium-reduced home-prepared food (Segev et al., 2010). But low potassium is actually the more common problem in kidney disease, and adding potassium-rich foods often fails to fix it because the cause is usually a leak rather than a shortage. Two opposite problems, one diagnosis. Your dog’s bloodwork picks the direction. This chart helps you steer once you know it.
Read this first: raw values, and cooking changes them
The values below are for raw vegetables. Cooking changes them, sometimes by half. Boiling pulls potassium out into the water, so a boiled and drained vegetable can come in far lower than what you see here. Roasting and steaming drive water off and leave the potassium behind, so those numbers go up. Check which state a value is describing before comparing it against another source.
Nineteen greens, two lenses
Tap a lens. The greens re-rank themselves. All values are mg per 100 g, raw.
Notice what just happened. Sixteen of the nineteen greens barely register on this lens, and three of them, beet greens, spinach, and Swiss chard, tower over everything else. The oxalate story is not a spectrum. It is a cliff.
*Collard greens are very high in calcium, and so I would pass on feeding collard greens to dogs with CKD.
A word about oxalates
I include the oxalate column because a client asked me about it, and it is a fair question with an honest answer: as of the time I published this, I was not able to find any clinical studies establishing upper limits for oxalates in dogs with CKD. In humans, dietary oxalate may have an important influence on the risk of forming calcium oxalate kidney stones (Mitchell et al., 2019), but we do not know what the allowances are for dogs.
So the chart above is not a rulebook, it is a sorting tool. If your dog has a history of calcium oxalate stones, the three greens on the cliff are easy to steer around, because as the potassium lens shows, there is a full shelf of gentler greens doing the same job. And if the oxalate column has you worried about greens in general, read the oxalate panic, examined, because for most dogs the fear does not hold up.
High or low: which problem does your dog actually have?
This chart tells you which vegetables are high. It does not tell you whether your dog needs less potassium or more, and those are opposite problems that show up under the same diagnosis. If you have not read it yet, the potassium guide covers why every commercial renal diet adds potassium, what happens to a dog when the number runs too high or too low, and how subcutaneous fluids change it.
Both charts live in the kidney disease guide.
And there is a third sort this page does not show: temperature. In TCM Dietetics most greens run cooling, which suits some kidney dogs and works against others, and the same nineteen vegetables would rank themselves differently again on that lens. That sort lives in the warming and cooling food energetics list.
Greens questions, answered plainly
Which green vegetables are lowest in potassium for dogs with kidney disease?
Cucumber, cabbage, green lettuce, asparagus, and green beans all sit under about 215 mg of potassium per 100 g raw, the gentlest end of the chart. Boiling and draining lowers any of them further, since potassium leaches into the cooking water and leaves with it.
Whether your dog needs the gentle end at all depends on the bloodwork, since low potassium is the more common problem in kidney disease.
Does cooking change the potassium in vegetables?
Yes, substantially. Boiling pulls potassium out into the water, so a boiled and drained vegetable can carry far less than its raw value, sometimes half. Steaming and roasting drive water off and concentrate what remains, so those preparations read higher, not lower, than raw.
This is why comparing values across sources goes wrong so often: one chart lists raw, another lists boiled, and the same vegetable appears in both wearing different numbers.
Are oxalates dangerous for dogs with kidney disease?
No upper limit for dietary oxalate has been established for dogs. In humans, dietary oxalate influences the risk of calcium oxalate kidney stones, so if your dog has a stone history, it is sensible to lean on the many low-oxalate greens and discuss the question with your vet.
The chart makes that easy: only three of the nineteen greens here carry heavy oxalate loads, and every job they do in the bowl can be done by something gentler.
The chart sorts the shelf. The recipe places the amounts.
If you are building a kidney bowl and the numbers are pulling in different directions, potassium one way, phosphorus another, appetite a third, that balancing act is what I do. Bring your dog’s bloodwork and we will build from it.
References
DuBose, T. D., Jr. (2017). Regulation of potassium homeostasis in CKD. Advances in Chronic Kidney Disease, 24(5), 305-314. https://doi.org/10.1053/j.ackd.2017.06.002
Gennari, F. J., & Segal, A. S. (2002). Hyperkalemia: An adaptive response in chronic renal insufficiency. Kidney International, 62(1), 1-9. https://doi.org/10.1046/j.1523-1755.2002.00350.x
Mitchell, T., Kumar, P., Reddy, T., Wood, K. D., Knight, J., Assimos, D. G., & Holmes, R. P. (2019). Dietary oxalate and kidney stone formation. American Journal of Physiology-Renal Physiology, 316(3), F409-F413. https://doi.org/10.1152/ajprenal.00373.2018
Segev, G., Fascetti, A. J., Weeth, L. P., & Cowgill, L. D. (2010). Correction of hyperkalemia in dogs with chronic kidney disease consuming commercial renal therapeutic diets by a potassium-reduced home-prepared diet. Journal of Veterinary Internal Medicine, 24(3), 546-550. https://doi.org/10.1111/j.1939-1676.2010.0488.x
Values shown are for raw vegetables, mg per 100 g. This page is education, not diagnosis; potassium decisions in a kidney dog are made with your veterinarian and your dog’s bloodwork.
Hannah Zulueta obtained her Certificate in Canine Nutrition from CASI Institute. She is also studying for her Doctorate in Acupuncture, Traditional Chinese Medicine, and Herbalism from the esteemed Pacific College of Health and Medicine. If you’re as keenly interested in health for yourself, visit her website for human health: Satori Acupuncture and Herbs.
She resides in San Diego with her three dogs, Maggie, Orbit, and Mr. Higgins.
She is available for one on one consultations. She develops evidence-based recipes that meet both NRC and AAFCO nutritional standards while integrating the therapeutic food principles of Traditional Chinese Veterinary Medicine into her formulations.
Additionally, you can find her sharing free content on Instagram.
