Is Spinach A Potent Kidney Stone Producer?

If you thought Spinach is a healthy vegetable, think again. When in the presence of high calcium containing foods, the spinach becomes a true poison. Here is why.



What Are Oxalates

Cooked spinach has 1,500 mg of oxalate in one cup!

Oxalic acid (or oxalate) is the component of spinach, chard, beet greens, and rhubarb that accounts for their sharp taste.


It also occurs in lower amounts in some other vegetables as well as in cocoa powder -chocolate (also present in other foods which keto-ers do not consume: peanuts, sweet potatoes, bran flakes, potato chips and French fries).


Your body naturally gets rid of oxalates, but in high amounts, they can have adverse effects.



High oxalate vegetables:


Chemical formula of Calcium Oxalate

Most people get between 200 and 300 milligrams of oxalates daily, which is extremely high.


Most concerning vegetable among all is the raw spinach with 656 of mg oxalate per 1 cup serving; 40 x higher than most other vegetables. Cooked spinach is even worse with 1,510 milligrams of oxalates per one cup serving.


Research shows that it would take about 25 grams of oxalic acid to cause death in a 145-pound person, which would equate to about 7.3 pounds of spinach.


Note: All oxalate amounts based on 1 cup raw vegetable, unless otherwise specified.


Major Health Complications Caused by High Oxalate Foods


Vulvar Pain (aka Vulvodynia)


Women occasionally experience a vulvar pain (aka vulvodynia) which negatively impacts their life. According to the healthcare specialists, this vulvar pain does not have an identifiable cause. Yet, we strongly believe that we came across the probable cause of the vulvar pain. It is the oxalates, in particular from cooked spinach. As some women consume spinach, raw or particularly cooked, they experience a vulvar pain for several days until their bodies have gotten rid of the oxalates (provided that they do not continue to consume more high oxalate foods)!


In women, vulvodynia, a painful condition that affects the vulva, is associated with oxalic acid. Studies have failed to find a clear connection between vulvodynia and oxalic acid, although one evaluation of 59 affected women concluded that urinary excretion of oxalates may aggravate this disorder.

The location, constancy and severity of the pain vary among sufferers. Some women experience pain in only one area of the vulva, while others experience pain in multiple areas.

The most commonly reported symptom is burning, but women’s descriptions of the pain vary. One woman reported her pain felt like “acid being poured on my skin,” while another described it as “constant knife-like pain.” Pain occurs spontaneously and is relatively constant, but there can be some periods of symptom relief. Activities that apply pressure to the vulva, such as prolonged sitting or sexual intercourse, typically exacerbate symptoms.



Kidney Stones


Few other health problems besides vulvodynia are linked to oxalic acid. It can cause formation of kidney stones. The oxalic acid in spinach can react with calcium from other foods in your digestive tract, forming calcium oxalate crystals. Most kidney stones are composed of calcium oxalate.

Calcium oxalate crystals (kidney stones) are insoluble and must be passed through your urinary tract intact. They are ragged, pincushion-shaped stones that can do huge damage to your internal plumbing on their way out.


Most kidney stones are composed of calcium oxalate. If you've had a kidney stone and want to avoid another one, you should definitely have a blood test for oxalate. Medical experts recommend that susceptible individuals follow a “low-oxalate diet” of less than 50 milligrams daily. Also, a calcium-rich diet will reduce the amount of oxalate your body absorbs, lessening the chance of stone formation – two to three servings daily of calcium-rich foods should do the trick.


There is no cut-off for what a low oxalate diet is. To be on the safe side, we at Comfort Keto will no longer include Spinach, Chard and Rubarb in our recipes.

Low Oxalate Greens


Here is the good stuff!

Note: All oxalate amounts based on 1 cup raw vegetable, unless otherwise specified.


  • Arugula (0 mg)

  • Romaine Lettuce (0 mg)

  • Iceberg Lettuce (0 mg)

  • Cabbage (0 mg)

  • Endive (0 mg)

  • Green Onions (0.5 mg per 2 stalks)

  • Bok Choy (1 mg)

  • Green Peas (1 mg)

  • Zucchini (1 mg)

  • Cucumbers (2 mg)

  • Kale (2 mg)

  • Broccoli (2 mg)

  • Brussels Sprouts (4 mg)

  • Mustard, Turnip and Collard Greens (4-10 mg)

  • Celery (5 mg)

  • Butter Lettuce (5 mg)

  • Asparagus (6 mg per 4 spears)

  • Green Bell Peppers (10 mg)


Talk to your doctor about oxalates and get a blood test for oxalate if you are experiencing vulvodynia or you are at risk for kidney stones.

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