Health Dangers of Oxalates

Health Dangers of Oxalates

Health Dangers of Oxalates

Health Dangers of Oxalates
Health Dangers of Oxalates

In our look at the Health Dangers of Plant-Based Foods we turn to oxalates. These are especially troublesome to the “health conscious.” It is nearly universally accepted that a large spinach salad topped with almonds and sesame seeds is a healthy meal. It goes without question that these leafy greens, that the cruciferous vegetables, that soy, and seeds are health foods. But contrary to popular belief, plants don’t want to be eaten. They use various mechanisms to deter predation, one of which is oxalates. Here we’re going to look at the health dangers of oxalates.

Health Dangers of Oxalates: Plant Growth and Protection

Plants have “motivations” for their survival, not human health. To protect themselves, plants use phytochemicals to deter predators from eating them. These special molecules fight back against fungi, insects, and animal predators – including us humans. Oxalates are such a molecule.

Because oxalates form into sharp crystal-like structures, they can prick a predator’s mouth, detering predation. Further, they prevent the absorption of minerals, deplete vitamins, and can bioaccumulate damaging tissues and organs. [rr]

Oxalate an an Antinutrient

Plants load their seeds with nutrition for the baby plant and they use oxalate as a way to store calcium for the new offspring. When seeds start to germinate they split off the oxalic acid which frees the calcium for the baby plant.

While oxalate is used as a calcium storage mechanism for plants, it’s a nutrient blocker (an antinutrient) for predators.

For example, many people think spinach is a good source of calcium. If you look at the label that’s what it will tell you. But it’s misguided. The calcium in spinach is pretty much useless. It’s all tied up in oxalate. And this is true for all high-oxalate foods.

There is a big difference in the nutrition measured in food and the nutrition that the body can actually absorb and use (bioavailability).

This is where standard nutrition guidelines start falling short.

If we eat 100% of our RDI (recommended daily intake) of calcium from spinach, but 100% of it is tied up in oxalate, we actually get 0% of the RDI.

Making matters worse, certain foods, like those high in oxalates, can increase the amount of a nutrients we need.

For example, if I were to eat a large bowl of spinach every day for lunch, I would increase my need for certain vitamins and minerals like b1 (thiamine), b6 (pyridoxine), and b7 (biotin).

Similarly to how phytic acid is a mineral thief, oxalic acid is a magnet for minerals, especially calcium. Oxalic acid grabs calcium and forms calcium oxalate – the main ingredient in kidney stones. [r, r]

Oxalate Bioaccumulation

Oxalate isn’t just an antinutrient that depletes calcium and iron, stealing essential vitamins and minerals.

While impairing nutrition as an antinutrient isn’t a good thing, oxalates ability to bioaccumulate and cause tissue and organ damage is what most people need to consider.

Oxalates can be toxic to humans in acute and chronic amounts. And while you can die if you eat too much oxalate at a single sitting, the toxicity is often more insidious. [r]

These oxalate crystals build up into bigger and bigger crystals. They bioaccumulate. As they accumulate the body deposits these sharp crystals throughout the body – in joints, muscles, and especially the kidneys. [r, r, r, r, r, r]

Oxalate Damage

With oxalate crystals growing and stored throughout the body, muscles start aching, eyes, ears, mouth, and throat can burn, and stones form in the kidneys.

Oxalate crystals cause renal damage; they are neurotoxic; they activate the immune system, upset the GI tract, deplete glutathione, and corrode connective tissue (via interference with hyaluronic acid).

Oxalates can impact nearly every bodily system. [rrrrrrr, r, r, r]

  • They can cause neurological symptoms which disturb sleep and adversely affect coordination, memory, learning, and concentration.
  • They cause pain via mast cell degranulation and histamine release.
  • Mysterious vulva pain, fibromyalgia, and carpal tunnel syndrome can all have oxalates causing or worsening the symptoms.
  • Increased calcium excretion and increased oxalic acid excretion ride hand-in-hand and are linked with osteoporosis.
  • Common practice for autism treatment is the elimination of oxalate-containing foods (as well as gluten, casein and soy).
  • Oxalates have even been implicit in breast cancer.

Oxalate Absorption

Absorption of oxalate differs from person to person. For some, oxalate is largely broken down in the gut and eliminated without causing issues. In others, a large percentage of consumed oxalate is absorbed.

Someone with a compromised gut, aka “leaky gut,” can see increased absorption of oxalate.

Not only does “leaky gut” allow more oxalate to get in, oxalate can be implicit in exacerbating leaky gut. The needle shape of oxalate crystals can perforate mucus membrane cells damaging the gut and increasing “leakiness”. [r, r, r, r, r, r]

Health Dangers of Oxalates: High-Oxalate Foods

It’s not only spinach pricks that can hurt you.

Many of the cruciferous vegetables like kale, cauliflower, and broccoli have high concentrations of oxalate.

Other culprits include chocolate, most nuts (especially cashews and almonds that are popular among the health conscious), and seeds like sesame and poppy seeds. [rr, r]

One of the worst offenders is soy. I remember when I was soy stupid – clueless that my soy protein shakes were loaded with oxalates.

Berries and beans. Potatoes and sweet potatoes. Okra. Swiss chard. Anything in the buckwheat family like sorrel. All high in oxalates.

Sorrel is actually worse than spinach and kale. And for some reason it is popular in fancy restaurants. There is a case report of a man who ordered sorrel soup for dinner. Two hours later he died in the hospital from acute oxalic acid poisoning. [r]

The man had poor metabolic health. He was obese and diabetic. And poor metabolic health further impairs the handling of oxalate. Yet, today we encourage obese diabetic patients to eat diets that are high in oxalates.

Health Dangers of Oxalates: Insidious Impact

Like other plant toxins, we don’t know (with any degree of accuracy) the frequency and degree of harm from oxalates thanks to a general lack of awareness. It often takes bioaccumulation to the point of an acute kidney injury until a healthcare practitioner even considers oxalate as a potential culprit. [r, r]

Sometimes patients with oxalate problems are asymptomatic until they find themselves trying to pass a kidney stone.

Sometimes mysterious lingering pain gets diagnosed as fibromyalgia or carpal tunnel syndrome without any knowledge as to why the pain is occuring.

Clearing the Crystals

Sometimes oxalate toxicity symptoms present when eating high-oxalate foods. But often they don’t. And sometimes symptoms don’t present until one stops eating oxalates.

For example, a flare up of pain may be from the release of stored oxalate that’s been consumed over a period of time.

The reason is that you have all these oxalate crystals accumulated in tissues, and now that you aren’t eating them, the body can process out the stores. The tissues start dissolving big crystals down into smaller crystals (and into their ion form) which are what cause much of the cellular damage and pain. But once back out into the bloodstream they can be excreted through the urinary tract. [r]

This process of breaking down and unloading the stored crystals for excretion can cause the same or worse symptoms than when they were originally eaten (a false positive reaction).

You’ve got to “re-eat” all that spinach.

Health Dangers of Oxalates: What (not) to do

Oxalate damage is from toxicity. It’s not a food sensitivity or allergen. So reversal of oxalate toxicity is a 2-step process:

  1. Stop eating it
  2. Excrete that which is stored up

Unfortunately, there isn’t a good way to determine how much oxalate damage you might have or how well you process them in general. Urine test are unreliable and a biopsy of tissue from the kidney is quite invasive. [r]

It’s also hard to correlate oxalate consumption with symptoms. As mentioned, you may be asymptomatic with insidious accumulative damage that doesn’t present until a serious event like kidney failure, or symptoms may only arise after you stop eating them.

The best thing you can do is limit the amount of oxalates you eat.

The major source of oxalates are from plant-based foods. But oxalate is also a byproduct of metabolism.

For example, excess Vitamin C can get converted to oxalate. Just another reason megadoses of Vitamin C might not be a good idea.

Cooking to Remove Oxalates

There’s also a false notion that you can just cook the oxalate out of your vegetables. This doesn’t work.

Oxalate and oxalic acid crystals are so durable that they are used by paleontologists to determine what people ate thousands of years ago. They aren’t destroyed by heat or cooking.

The one thing that can help is boiling these vegetables in water. The soluble parts of oxalic acid that aren’t crystalized can leach out into the water. So if you boil your broccoli to mush you can reduce the oxalate concentration by maybe a third. [r]

Low Oxalate Diet

My Dad recently sent me this picture of his new Low Oxalate Meal Plan, given to him by his nephrologist after another battle with kidney stones.

Low Oxalate Diet

I always appreciate it when a healthcare provider gives information on prevention and root causes.

If you go through this Low Oxalate Meal Plan, what you’ll notice is that when limiting oxalates you necessarily start moving to a meat-based diet.

My Dad is now using the Meat Health Method to transition into his low oxalate diet.
I talk more about this method in the Meat Health Masterclass.

There are a lot of misconceptions around “healthy” food, perhaps epitomized by the “green smoothie cleanse.” People want to do the right thing, but are often “stabbing” themselves in the foot (or more accurately the kidney).

But a green smoothie “cleanse” is more likely to lead you to needing an oxalate cleanse.

[NOTE: You can now access the complete “Health Dangers of a Plant-Based Diet” series here]:

Resources [r]: Many resources were used in the research and writing of this article. It’s often impossible for me to cite everything that has helped draw the conclusions presented. But I wanted to make a special note on the “Journal of Evolution and Health” Volume 2, Issue 3, 5/2018 and it’s references that were especially helpful. This is a great place to start if interested in learning more about oxalates.

146 Replies to “Health Dangers of Oxalates”

  1. Kevin, I take Chaga tea regularly, and it is high in oxalates, do they leach out to the tea in a harmful amount since I leave the grounds with any crystal behind pouring through a super-fine sieve?

    1. They definitely can leach out.

      To a harmful amount? That depends on a lot of things, but if you have problems with oxalate overload, then might be a good idea to go without.

      1. Do you know if the oxalates in the water will stay suspended in the water or settle to the bottom of the cooking pot so the liquid could be carefully poured off without them?

        1. So yes, boiling can significantly reduce soluble oxalate content (somewhere between 30-87%) but as you mention they will be in the water so it is best to dispose of it. And in the absence of a distillation and filtering process, I’d assume they are in the water (some suspended, some settled).

  2. To all who are waiting for relief after stopping high oxylate foods, it took 11 weeks for the dumping effect to disappear for me. I had UTIs for years, which disappeared after quitting oxylates. Burning soles of the feet are also a symptom.

    1. Weird I have had burning feet for sometime now. I started the carnivore diet 10 days ago. Did you see improvements along the way? Or just after 11 weeks totally better?

      1. I can’t say for a total carnivore diet as I have never done that. With low oxylate diet, symptoms were intermittent but decreasing. I still get burning soles of feet a couple of hours after eating some foods, especially bananas, oats or whole grain wheat.

  3. So with spinach and potatoes containing large amounts of potassium and 4700mg a day being recommended (especially for someone with high bp) how in the world would you go about getting that much potassium?

  4. So, in your opinion, by stopping oxalate intake, could I possibly diminish the size of the calcium oxalate kidney stones in both my kidneys over a period of time? I have a 12 mm in the left that my urologist has tried to retrieve thru uteroscopy and tried to blast thru lithotripsy, but has been unsuccessful thus far. If it diminished in size, maybe I could pass it without surgery. How long would it take to diminish in size?

    1. Stopping oxalates would only help keep it from getting larger. Search for ‘dissolve kidney stones’. Apple cider vinegar pills and/or potassium citrate are you best bets before prescription drugs. Some types of stones can’t be dissolved.

  5. Wow at last some answers to my nightmare. Hi thanks so much Kevin! I will follow your recomm ndation and stop eating oxalates of immediately after a horrendous bout if toxic overload this week. My main discomfort at the moment is the stinging eyes. My mother ended up with Macular Degenration which I have read is caused by acid build up. However the best protection many say is plenty of LEAFY GREENS! How can thy get to things sooooo wrong? I have tried putting chamomile tea bags and slices of cucumber on my eyes but the stinging continues. Any suggestions? And, are here any vegetables/fruits you recommend to supplement type meat based diet?

    1. I really can’t comment on the stinging eyes (besides working with a doctor) – sorry for not being more help!

      I do not supplement with any fruits or vegetables – meat provides complete nutrition 🙂

  6. What’s your thoughts on when eating a oxalate food, to combine a calcium source, maybe dairy, to have the oxalate bind to the calcium for it to be excreted through stool?
    Another,…isn’t meat harder on the kidneys, causing uric acic stones? Or is that just from proteins in foods?

    1. Yes that can help, though I find just not eating high oxalate foods to be a better solution.

      And no, that is a myth that has somehow perpetuated far longer and further than it should have (I’ll be writing on it soon)

    2. I repeatedly tried that i.e combining high oxalate food with dairy/calcimu source but my body still reacted to the oxalate i.e. didnt work.

  7. Hi Kevin – Thanks for responding. I thought I saw where you sent an email stating to ask questions on a Facebook page. If so, what’s the Facebook page called?

  8. Hi Kevin
    We make a cucumber soup and eat it daily.
    I make it from 80%cucumber some kale or spinach and green herbs such as coriander.
    Is it only the spinach kale containing cucumber.


    1. Most lists have cucumber as low oxalate.

      Most lists have kale and spinach as high oxalate (spinach has one of the highest oxalate content of all foods). Some lists have kale as ok for a low oxalate diet.

  9. Kevin, thank you for this article. My husband had 3 OATS tests – last one in 2016. The doctor just noticed last year that all 3 showed high oxalates. His cognitive function has gotten worse and has trouble speaking the correct words most of the time. One time he urinated a few months ago and I noticed crystals in the urine with red (I guess it was blood) attached to them. I didn’t know what it was and then I thought could that be oxalates. We unfortunately have been eating sweet potatoes everyday sometimes twice a day. He has been given high doses of Vit. C at times. A naturopath then gave him something called Oxalate Scavenger by Methyl Genetic Nutrition. We’re not with that Dr. any longer, but I’m thinking my husband should be taking this. Also, the current practitioner recommended celery juice (16oz./day). This is a whole stalk and sometimes more. Should this be stopped? Thank you again for posting this article. Great information.

    1. Thanks for reading Pat and sorry to hear about your husband’s struggles. Of course, I can’t give medical advice here, but I would recommend working with your doctor and perhaps sending him some of the information here.

    2. Oxalate Scavenger hits all the right notes. It even has Vitamin B6. That alone does the trick for many people.

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