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Oxalates toxicity: Is your “healthy” green smoothie poisoning you?

By 6 December 20202 Comments

Oxalate toxicity is not well known, and whilst its symptoms are painful and serious, its reversal can be straightforward 


Oxalate toxicity is under-recognised and under-diagnosed.  It can be caused by genetic factors, a yeast fungus infection, diet, or a combination.  Symptoms can include fatigue, poor sleep, joint and muscle aches and pains, brain fog, eye pain, burning sensation, vulvar pain and kidney stones.  You are more at risk of it if you have a leaky gut, and it may interfere with body systems causing anaemia, heart arrhythmia, underactive thyroid, interstitial cystitis, osteoporosis, fibromyalgia or carpal tunnel syndrome.  One problem is that it is counter-intuitive, often being caused by a diet rich in leafy greens!  The toxicity can be reversed by gradually reducing your oxalate intake, moving a bit towards a healing carnivorous diet, though you may experience greater pain at first as the oxalate is eliminated from your system.

Her diet of leafy greens was actually part of the problem

This 70-year-old lady presented with fatigue, tremor, rigidity and slow movement; she had difficulty maintaining an erect standing posture, necessitating the use of a Zimmer frame.  She attended the neurology clinic but did not respond to Parkinson’s disease medication (Madopar). Her head MRI scan was normal.

She also had ongoing symptoms of watery or itchy eyes, sneezing attacks, excessive mucus production, frequent throat clearing, hoarseness, constipation, joint pain and stiffness, arthritis, muscle pain, a feeling of weakness, low weight, poor physical coordination, depression, and frequent or urgent urination.  This was suggestive of an upper respiratory tract candida infection.

Nutritional support gave some improvement – she reported having more mental energy, good facial expression and eye movements – but her spinal and limb muscles deteriorated.

Her shoulder girdle, limbs and joints had become increasingly sore and rigid.  The patient had an ongoing candida infection and went on a “healthy” high-oxalate diet (leafy greens, nuts and seeds.)  The combination of the infection and the diet resulted in a high oxalate level.

This patient’s story reflects that not every “healthy” diet is good for everyone.

In this article, I will discuss Oxalate toxicity syndrome, a common but under-recognised and under-diagnosed condition – how it happens, the clinical features and the actions to take to keep the problem at bay.

High oxalate can be caused by genetic variants, diet (real healthy & western processed diet), a yeast fungus infection or metabolic by-product of vitamin C. Foods high in oxalates include almonds, beetroot, chocolate, spinach, French fries, potatoes, soy products, black tea, instant coffee, leafy greens, rhubarb, lentils, strawberries and raspberries, Turmeric but not curcumin, whole wheat flour products, bran & other cereals.  Oxalate poisoning was recognised as long ago as 1850 and seen as a seasonal problem, prevalent in spring and summer when fresh green food is abundant.

Oxalates help the storage of calcium in plants but may be poisonous to humans, resulting in acute or chronic toxicity.  Oxalates circulate in the blood as oxalic acid, which can easily combine with calcium to form calcium oxalate crystals and kidney stones.

Oxalates can also accumulate in the body tissues causing inflammation, autoimmune diseases, interference with mitochondrial function and energy production, and can result in neurological damage.

This can result in unexplained symptoms of fatigue, poor sleep, heart arrhythmia, joint and muscle pains similar to fibromyalgia, brain fog, eye pain, burning urine (interstitial cystitis), vulvar pain and kidney stones.

Oxalates can damage the gut lining, and having a leaky gut allows the absorption of more oxalates into the body to cause toxicity.

A green smoothie contains 20 times the oxalate you can safely take in a day! 

Pumpkin, sunflower, and flax seeds are the safest to eat as they contain a lower quantity of oxalates.  Olives are high in oxalates, but olive oil is not.

Calcium has a special love for oxalates, forming calcium oxalate kidney stones.  This can result in groin pain and cloudy, smelly urine, often with blood.  It can also cause urgent or frequent urination.  Kidney stones cause severe intermittent renal colic.  It is also associated with recurrent urinary infection, which often presents with fever and chills.

To avoid oxalate kidney stones, drink adequate fluids to avoid dehydration and eat food low in oxalates or any food in moderation.

Oxalates can also accumulate in the heart, causing attacks of arrhythmia.  This is observed in those with high oxalates consumption – for example, those who eat almond bread and drink spinach smoothies on a regular basis.  This can be attributed to localised acidosis and potassium depletion.  These patients need rehydration, and their minerals replenished, in particular potassium, calcium and magnesium.

Oxalate poisoning can also cause diaphragmatic hiccough, a symptom prevalent in chronic renal failure and terminally ill patients.

A green smoothie is 20 times what you can safely take in a day!  Potatoes and sweet potatoes are also high in oxalates when consumed in large quantities.  It would require a lot of vitamin B and minerals to process them.

Hyperoxaluria can be caused by an inherited disorder of the intestine

Hyperoxaluria (high level of oxalates in the urine) symptoms include pain when urinating.  Some patients presenting with hyperoxaluria are eating large amounts of food high in oxalates, so avoid these foodstuffs if you have enteric hyperoxaluria.

Primary hyperoxaluria is when your kidneys fail because the body can no longer eliminate the extra load of oxalates: they then stay in your bloodstream and are deposited in your eyes, bones, skin, muscles and blood vessels, resulting in multi-system problems.

Primary hyperoxaluria is a rare inherited condition where the liver does not create enough of the enzyme that prevents the overproduction of oxalates.   It cannot be eliminated through the kidneys, so the excess oxalate combines with calcium to create kidney stones and crystals, which can damage the kidney and cause kidney failure.

Eating a high quantity of oxalates increases your need for certain vitamins (B6, but also B7 and B1) and minerals (calcium, magnesium, iron, zinc) to process it.  Oxalates also deplete calcium, causing osteoporosis and iron, resulting in anaemia and other essential vitamins and minerals.

Oxalates also activate the immune system causing systemic inflammation, depleting glutathione, the master antioxidant resulting in an oxidative stress crisis, and interfering with hyaluronic acid necessary for healthy connective tissues.

Oxalates can cause neurological symptoms, mast cell degranulation and histamine release, vulva pain, fibromyalgia and carpal tunnel syndrome.  Increased calcium excretion can result in osteoporosis.  Oxalate is eliminated routinely in the management of autism.

In guarding against oxalates, you should also consider eliminating gluten, dairy, sugar and refined carbohydrates, as these can damage the gut lining and result in a leaky gut.

Patients are usually asymptomatic until they form kidney stones

Oxalates patients are usually asymptomatic until they form kidney stones, which cause a lot of pain when they start to move.  Patients may present earlier with body aches, pains, fibromyalgia, or carpal tunnel syndrome.

The body starts dissolving the crystals, causing cellular damage and pain.  Once these crystals are back in circulation and then excreted in the urine, the symptoms start to ease.  The process of breaking down and uploading the stored crystals can cause the same or even worse symptoms than when they were originally deposited.

Lemon juice contains citric acid, which helps to weaken the bonds of oxalate crystals and makes them easier to separate.  Half a cup of lemon juice daily will help your kidneys release all of the oxalates.

High oxalates can be diagnosed by a urine test (24-hour urine sample) to check oxalate levels in urine.  Blood tests can check the gene that causes Dent disease.  And radiology (ultrasound x-ray, CT or MRI scans) can show Musculoskeletal inflammation and stones in the kidneys.

The supplements recommended for those struggling with oxalate poisoning are calcium citrate, potassium citrate, magnesium citrate and potassium carbonate.   The purpose of the calcium citrate is to help release oxalates from your tissues, so make sure it has not had vitamin D in it because vitamin D encourages the absorption of oxalates.

High oxalate + leaky bowel = double the problem

You should reduce your oxalate intake if you have a damaged gut lining because your leaky bowel can absorb more oxalates if you suffer from inflammatory, autoimmune disease, mineral depletion, or thyroid disease.  Oxalates is also a problem for obese diabetics.

The carnivore diet is good for the body, which will start dissolving and eliminating oxalates when you switch from an oxalate-rich diet to a carnivore one.  This highlights the healing effect of animal food such as bone broth – particularly for people with chronic arthritis and other pain.

Probiotics can prevent kidney stones

 Oxalates combine with calcium to form calcium oxalate in 80% of kidney stones. This attracted attention to lowering food oxalates in the gut before it gets absorbed to form kidney stones. The research initially focused on Oxalobacter formigenes, a bacterium that breaks down oxalates in the gut, reduces oxalates absorption, and prevents kidney stones. However, the bacteria was ineffective when administered with or closer to antibiotics. The research suggested that a mixture of microorganisms, including Bifidobacterium and Lactobacillus, effectively degrades oxalate in the gut and prevents kidney stones.

The best oxalate cleanse is simply to reduce your consumption gradually and wait.  Just be aware that, in the short term, you may have to go through a flareup of symptoms when the stored oxalate is released.

I hope that this helps, my friends, and, as always, if you have any questions or any experience of oxalate toxicity that you would be happy to share, please do so.  Your sharing may help others recognise, treat, and reverse their toxicity.  Thank you.



Probiotics in the prevention of the calcium oxalate urolithiasis



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