Can Eating Too Much ‘Kale’ Cause Kidney Stones?

Gut bacteria is very important for our health. That’s why it’s essential we get enough natural fiber in our foods. And, kale qualifies. But, it’s a good idea to cook your kale, not have a huge salad of it. Why?

‘Drinking enough liquid, mainly water, is the most important thing you can do to prevent kidney stones [1]’.

Some health sources say that oxalic acid is found in green leafy vegetables like spinach, chard and kale. It is said that when urine has too much calcium and oxalate kidneys may not be able to dilute it adequately, and then those same calcium and oxalate crystals may combine forming what we know as stones in our kidneys (kidney stones.)

‘If you are worried about kidney stones, add freshly squeezed lemon juice on your daily salad. Doing so may help reduce risk kidney stone formation. Fortunately, I eat mostly butter lettuce salads with only a handful of power greens (spinach, kale, mizuna and chard)’

The experts divided on the issue say there’s not enough oxalic acid in kale to cause any harm. In other words, kale is among one of the lowest in oxalic acid, compared to spinach, mizuna, arugula, beet greens and swiss chard.

“There is inherent wisdom in the old saying ‘Do all things in moderation'”.

They say, you couldn’t eat enough kale to cause kidney stones in the first place. So, by that, I wouldn’t worry so much about that leafy green. Although, I just wouldn’t make a practice of eating cups and cups of the others and drink huge green smoothies packed with them throughout the day.

For example, the bulk of my daily salads is butter lettuce with a handful of power greens. And, when we make our daily green smoothie, my wife puts a small handful of spinach in.

‘Which so called expert does one believe, when there is so much disagreement among them’?

Spinach and swiss chard (See graph with high oxalic acid foods) are those we have to use care with the amounts we eat, because each has high amounts of oxalic acid. Therefore, for your own peace of mind you could consider eating these and others known to be high in oxalic acid in moderation. Furthermore, boil the above because this process will reduce oxalic acid more than steaming.

Did you know that a diet lacking calcium and high in sodium increases risk of developing kidney stones? So, broccoli, beans and Brussels sprouts could be used as healthy alternatives for calcium in replacement of high oxalic acid plant based whole food.

‘Boiling markedly reduced soluble oxalate content by 30-87% and was more effective than steaming (5-53%) and baking (used only for potatoes, no oxalate loss)[2]’.

Kale is good for us because like other leafy greens contains essential micronutrients, vitamins and generous amounts of fiber. Fiber will help prevent disease. It’s like a broom sweeping the muck out our intestines.

‘Oxalate arthritis is often difficult to distinguish from other causes of crystalline arthritis, and identification of calcium oxalate crystals within the synovial fluid is required for diagnosis [3]’.

I may have had joint pain and stiffness from eating too much spinach, soy products, black tea, potatoes, chocolate, wheat bread, almonds, cashews, peanuts, beans and tahini.

The above are also high oxalate foods (some also high in lectins.) Most of these, I have eliminated or at least have greatly reduced from my diet, but not all. For example, I pressure cook my potatoes, beans and rice to lower lectin potency.

*Further reading- low-oxalate-diet

*Don’t forget Kale (be sure to buy organic) is sprayed with pesticide EWG_FN-2020_Guide

Source- 1 “Eating, Diet, & Nutrition for Kidney Stones.” National Institute of Diabetes and Digestive and Kidney Diseases, U.S. Department of Health and Human Services, 1 May 2017,

2 M;, Chai W;Liebman. “Effect of Different Cooking Methods on Vegetable Oxalate Content.” Journal of Agricultural and Food Chemistry, U.S. National Library of Medicine,

3 Lorenz, Elizabeth C, et al. “Update on Oxalate Crystal Disease.” Current Rheumatology Reports, U.S. National Library of Medicine, July 2013,

Note- before you change your diet consult your doctor.

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