Oxalic Acid Controversy

| August 11, 2012 | 20 Comments

Many people are afraid of eating too many greens because they have heard the possible dangers of eating too much oxalic acid.  Greens, like certain plant foods are high in oxalic acid.

You might already guess my stance on this controversy but just in case there is any confusion I will spell out my personal reaction to these concerns at the end of this post.

The Problem:

1.  Oxalic acid binds with some nutrients, making them inaccessible to the body. To eat large amounts of high oxalic foods over a period of weeks to months may result in nutritional deficiencies, most notably of calcium.

2.  Oxalic acid is associated with the formation of kidney stones.  If you have kidney problems, your doctor may advise you against eating foods with high levels.

3.  Oxalic acid poisoning symptoms include weakness, burning in the mouth, death from cardiovascular collapse, on the respiratory system, throat – burning in the throat, abdominal pain, nausea, vomiting, diarrhea, convulsions, and coma.

4.  Individuals with gout, rheumatoid arthritis, or certain forms of chronic vulvar pain are advised to avoid foods high in oxalic acid or oxalates.

For Clarity: How toxic is Oxalic Acid?

“From an MSDS (Material Safety Data Sheet) for Oxalic acid, LD50 (LD50 is the Median Lethal Dose, which is the dose of a drug or chemical predicted to produce a lethal effect in 50 percent of the subjects to whom the dose is given) in rats is 375 mg/kg. So for a person about 145 pounds (65.7 kg) that’s about 25 grams of pure oxalic acid required to cause death. Rhubarb leaves are probably around 0.5% oxalic acid, so that you would need to eat quite a large serving of leaves, like 5 kg (11 lbs), to get that 24 grams of oxalic acid. Note that it will only require a fraction of that to cause sickness.”  – The Rhubarb Compendium

Is This Possible?  The Murky Middle

  • Oxalic acid is a naturally occurring substance in plants, animals, and in humans.
  • I often think that anything with the word acid in it will scare people but not all acid are bad.  Remember that Omega 3 which everyone is trying to put into their bodies is an essential fatty acid. That might be a bad example of course since everyone is also scared of the word ‘fat’.
  • Rhubarb contains high amounts of oxalic acid.  If your weight is 145 pounds, you would have to consume about 25 grams of pure oxalic acid to cause death. That means you would have to eat about 11 pounds of rhubarb!
  • Foods that contain significant amounts of oxalic acid are ( in order from highest to lowest): buckwheat, star fruit, black pepper, parsley, poppy seed, rhubarb stalks, amaranth, spinach, chard, beets, cocoa, chocolate, most nuts, most berries, and beans. If you had to really avoid oxalic acid that would be difficult.
  • There is a thought that cooking greens will lower the oxalate content but food chemistry studies show that blanching or boiling of green leafy vegetables does not make a significant difference.  Thus, green smoothies do not have more oxalic acid in them contrary to some thought.

Benefits and Rebuttals: The other side of the oxalic acid story:

1. It has been assumed that black tea due to its high oxalate content increases kidney stone formation but recent research has shown it to have a preventive effect.

2Victoria Boutenko of the Raw Food Family sites research on how high oxalic acid foods actually reduce the formation of kidney stones.  The true cause of kidney stones is not oxalic acid but actually animal protein.

3.  Oxalic acid linked to the cure or prevention of cancer:

  • When cancer is diagnosed there is always a low level of oxalic acid in the blood. It is important to have the enough oxalic acid in our blood because this eliminates all abnormal cells without harmful side effects
  • Every alternative cancer cure that is successful is filled with foods, herbs, grasses, and teas that are full of high amounts of oxalic acid.
  • American Cancer Society conducted tests over 50 years ago using oxalic acid in the treatment of cancer and the results in papers and evidence were positive.
  • “When oxalic acid is in our blood; in foods & beverages we eat and drink, and testimonials confirm oxalic acid kills cancer cells, virus, bacteria, and decalcifies the material in plaque in arteries; and is in the blood of all warm blooded mammals”. From booklet “Questions and Answers About E- M- F, Electric and Magnetic Fields Associated with the Use of Electric Power
  • Radiation will decompose oxalic acid in the blood.  This usually weakens the immune system so the body is unable to fight off viral or bacterial disease.  Is this why many cancer patients die from cancer related to viral pneumonia.



4. Oxalic acid is needed by our body:

It is important for colon health. When we do not get enough from our diet, the body makes it from ascorbic acid.

5. Eating foods containing oxalates and calcium together may reduce the risk of stones according to some studies because oxalate binds with calcium in the intestine.

6. All the foods high in antioxidants are also high in oxalic acid.

7. Some of the healthiest foods on the planet are high in oxalic acid.

Even if you could avoid these foods you would not want to!

Plant foods with high concentrations of oxalic acid (over 200 ppm) include (but are not limited to): lamb’s-quarter, buckwheat, star fruit, black pepper, purslane, poppy seeds, rhubarb, tea, spinach, plantains, cocoa and chocolate, ginger, almonds, cashews, garden sorrel, mustard greens, bell peppers, sweet potatoes, soybeans, tomatillos, beets and beet greens, oats, pumpkin, cabbage, green beans, mango, eggplant, tomatoes, lentils, and parsnips. From the USDA

My Own Personal Opinion

  • Before you start limiting greens and nuts and buckwheat and cabbage…… totally eliminate junk food and fast food, and packaged food and micro-waved food and white sugar and white flour.
  • Most people need to eat more greens, not less.
  • I love my green smoothies for breakfast; they taste good and are filled with so much nutrition.
  • One of the great things about greens are that they are alkaline forming and many of us are way too acidic. I recommend this in all my health coaching and Healthy Weekend Web BootCamps.

Below are a few powerfoods HIGH in oxalic acid.  You can read their many benefits.

Beets: Aphrodisiac, Brain Booster, Pain Reliever & More

Dandelion Greens: I love to add this in the summer.

Spinach is the First Green Powerfood How could Popeye be wrong?

About Diana Herrington

I am the Founder and Author at Real Food For Life. Have been teaching cooking classes worldwide since 1982. Create original, healthy recipes and menus, which are gluten free and white sugar free. Also, the author of the GREEN means LEAN and Balance Your Body e-books. I turned a debilitating health crisis into a passion for helping others with healthy, sugar free, gluten free eating and cooking.




Category: Health Tips, Nutrition

Comments (20)

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  1. Francesca Meney says:

    I have found your post very interesting and would like to continue to follow your future tips on kidney diets.

  2. Annie says:

    Wow! You scared me at first! lol I thought ” Oh man more things I thought were good for me and now there bad for me! ” ( Like agave) What am I going to eat!!! Ha ha. Thanks for the info(:

    Happy Halloween!!!

  3. TropicBob says:

    Another controversy with foods and nutrition. I eat buckwheat (organic) pancakes, have 2 starfruit (carambola) trees (juice 6 a day for approx 3 months every year), grow and eat chard, mustard greens, green beans, tomatoes, eggplant, and mango’s every day at least 6 months of the year. I am either extremely healthy or must have 30 kidney stones developing inside.

  4. Annie, sorry for the scare. We just want to create more awareness and that means getting people to read the info. Hope you are not giving up all that healthy food unless you do really have a health concern related to them.

    Yes Bob a controversy for sure. I eat all those foods too and am healthy! No I am not giving up my greens! Happy to hear you are not either.

  5. Rolande says:

    I agree, im in the process of reading Wheat Belly and learned that when your body PH is acid it will leech calcium from your bones to balance the PH to more normal levels. However don’t think it’s the greens you eat! Cut out the wheat and sugars and junk food !


  6. Eliza says:

    I often hear the warning that people with rheumatoid arthritis should avoid foods high in oxalic acid, but I’ve never heard the reason. Do you know?

  7. Eliza, as I say above it is good to avoid foods high in oxalic acid for arthritis. I am not an science expert on this subject. Go to http://oxalicacidinfo.com for more info.
    My opinion is that we need to eat foods that have oxalic acid in them because they are foods with lots of nutrition. It is important to have a balanced diet. But do check with your doctor.

  8. Eliza says:

    Thank you for your response and suggested link. I’ve seen the same statement cautioning against oxalic acid for people with rheumatoid arthritis in many places, but I’ve never seen anyone cite a source. I found this on Wikipedia: http://en.wikipedia.org/wiki/Oxalic_acid “The toxicity of oxalic acid is due to kidney failure, which arises because it causes precipitation of solid calcium oxalate, the main component of kidney stones. Oxalic acid can also cause joint pain due to the formation of similar precipitates in the joints.” Unfortunately no source cited.
    Again on Wikipedia: http://en.wikipedia.org/wiki/Oxalate “Those with kidney disorders, gout, rheumatoid arthritis, or certain forms of chronic vulvar pain (vulvodynia) are typically advised to avoid foods high in oxalic acid.” Again no source cited. It’s interesting how the same warning is repeated so often without a reference for its basis. Maybe someday I’ll find the source! Thank you again.

  9. Maureen says:


  10. paty says:

    Thanks for the beet information. I use a whole beet in my morning smoothie along with: a green granny smith apple, 3 cups of kale, 1 cup of spinach, 1 carrot, 1/2 cucumber and a stalk of celery. If I have bluenerries I add about 1/4 cup. Really greay tasting…sometimes the amount works into Two days of smoothies.

  11. Tyrker says:

    “Eating foods containing oxalates and calcium together may reduce the risk of stones according to some studies because oxalate binds with calcium in the intestine.”

    That would mean that eating foods high in both calcium and oxalic acid – such as poppy seeds and walnut – would pose no real threat as calcium oxalate formed in the gut cannot be absorbed into the bloodstream (however, this would also mean that these foods are actually poor sources of dietary calcium as the body cannot utilise it). Food for thought.

  12. Karlie says:

    This past May, I was in Rome & the hotel I stayed at had amazing breakfasts. Since I have problems with Milk & all Grains & I didn’t know what meals would be available later in the day, I’d fill up on those amazing breakfasts of among other things -KIWIS -1 or more daily for 11 days. When I returned home – I continued eating KIWIS daily because they reminded me of Rome & I’d also put powdered dried Spinach in my lunchtime broth -almost daily. Well…since returning I’ve felt like I’ve been beaten & kicked & I could hardly move. I couldn’t take Aspirin or Advil because it raises my Blood Pressure so nothing buffered the pain. I did drop the KIWIS from my diet by happenstance & because of hotter weather I didn’t have the Spinach Broth & only now weeks later I am starting to feel less arthritic. I would never-ever have thought of the KIWIS as the problem or even heard of Oxalic Acid. This info. is a life saver for me – it is a real public-service you have done here. ( I will continue eating these foods…but always cautiously & in moderation!! ) -Thx a million!!

  13. Randy Fritz says:

    thanks Karlie for sharing your experience. I hope you stay well!

  14. This article is a breath of fresh air. I once read that a healthy person has to eat 11lbs of oxalic acid in order to get a negative effect. Is this true?

  15. Joanne says:

    I just ate 2 small raw beets I harvested from my garden. The back of my throat is burning.

    Never had this happen before.

  16. Pone says:

    What is a source of calcium that could be added into beet juice to neutralize most of the oxalates? What amount of this calcium containing food would be needed per some defined weight of beet?

  17. Tom says:

    Don’t forget to mention that Oxalic Acid is also shown to cure cancer. Most cancer patients are low in Oxalic Acid. Oxalic Acid is a calcium ion channel blocker which blocks communications between cells. This block prevents cancer cells from communicating with good cells to infect them. Also new calcium ion channel 1 blockers are being developed based on Oxalic Acid that will block pain receptors at the source instead of transmitting the pain signal to the brain. Currently most pain medications are opiates based on either codeine or morphine which morph the pain signal once received by the brain. The new calcium ion channel 1 pain blocker will revolutionize the pain medication industry and purportedly has little to no side effects.

  18. crystal says:

    Did some research when I had a snapped collar bone at 46…concerned about calcium and healing, especially as a woman.

    what I found was that Calcium can not be properly obsorbed(thus facilitate healing a broken bone) with out a hand shake from vitamin C….

    This is known but not talked about…cereal commercial…part of a balanced breakfast…see bowl of milk and cereal AND a glass of orange juice…

    I could never figure that out until now as who would want oj on top of milk and cereal…you sure wouldn’t be thirsty, eh?

    Calcium is also used to bind metals to leave the body…wonder how many of those stones are wondering calcium being shed due to NO vitamin C with those suppliments???? read the lable of the cal/mag we buy…no C…

    Some how I have to think that C added to that soup of Oxalic Acid and calcium makes it all work…

    Also Dr. Walker, famed juice guru, said that the body can use Oxalic Acid if it is unheated…so this ‘wilting’ of our spinach would actually exacerbate the problem.

    Nuff said

  19. Sunny Holmes says:

    Your info is greatly appreciated. I have osteoporosis and have had several spinal compression fractures. I’m a 70 yr old woman. Should I be concerned about oxalic acid?

  20. Yohann Bach says:

    Thank you for an excellent intro on oxalic acid :-) I agree all this talk of anti-nutrients is overblown and even a bit silly when you start to know a bit more (seems people with an axe to grind like to look to this).

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