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  • Writer's pictureOrsolya Szathmari

Oxalates And Your (Un)Health

What is oxalate?

Oxalate is a chemical compound found mostly in plants, but also in animals and humans in very small amounts. It is a metabolic waste product in mammals, with no known function.

Oxalate is the conjugate base of oxalic acid. In nature this organic acid is found in the form of oxalate salts, bound with a mineral such as calcium, potassium, magnesium or sodium. Oxalic acid by itself is very toxic.

Calcium oxalate is found in many plants, mostly in the leaves, in different quantities. It has a central role in a variety of important functions, such as calcium regulation, seed germination and protection from herbivorous animals.

When animals, including humans, eat these plants, the oxalic acid is liberated from the plant and might cause various health problems.

So the advice “The more plants you eat, the healthier you become” is not true, at least not for everybody. There are people who get worse when eating more plants because of different plant toxins, such as oxalates, phytic acid, lectins and alkaloids. However, oxalates differ from other plant toxins because they are accumulating in the body with time and it is very hard to get rid of them.

Oxalate is a chemical compound found mostly in plants, but also in animals and humans in very small amounts. It is a metabolic waste product in mammals, with no known function.

Foods high in oxalate

Oxalates are found abundantly in many so called super foods, mostly in green leafy vegetables, but also in other foods.

Highest oxalate foods are:

  • spinach, Swiss chard, beets

  • figs

  • wheat and most grains, amaranth, buckwheat

  • beans

  • many nuts and seeds, especially almonds

  • raw cocoa powder, dark chocolate

  • cinnamon, black pepper, turmeric, cumin

  • cassava, potato, sweet potato, beetroot, carrot

  • star fruit, kiwi, clementine, raspberries

Many "superfoods" are very high in oxalates, especially in a gluten- and dairy-free diet. While wheat and most grains are high as well, the gluten-free alternatives are even higher in oxalates. For example, almond flour and any kind of nut flour contain a large amount of them.

The absolute worst is a typical vegan green smoothie with almond milk, spinach, turmeric, cinnamon, berries, and raw cocoa powder. The recommended maximum daily intake of oxalates is 150 mg and a popular green smoothie can contain up to 1.5 g of it!

Rhubarb has the highest level of all plants. Excessive consumption of rhubarb can cause acute kidney failure. Another popular recipe that has a very high amount is celery juice.

Oxalate toxicity

The prototypical oxalate related health problem is kidney stones. The stones are oxalate crystal deposits, causing lots of damage to the kidneys. 80% of kidney stones are made of Ca-oxalate. The general recommendation for this condition is a low-oxalate diet.

However, it can accumulate in almost any organ or tissue in the body. Some people with oxalate problems do not develop kidney stones but have other health issues. Oxalate crystal deposits can cause problems in the oesophagus, stomach or intestine (causing leaky gut). Oxalate goes to the liver, the heart and lungs, to arteries, capillaries and veins, where it is highly irritant, causing endothelial dysfunction, inflammation to the blood vessels. It is dangerous for the vascular system.

High amounts also activate the immune system causing immunological problems.

Oxalate effects thyroid hormone production and causes antibody response.

Joint pain can also caused by oxalate as deposits in joints. These cause inflammation and unexplained joint pain, mimicking arthritis without an autoimmune process.

It can cause fibromyalgia-like muscle pain. When tested, many people with fibromyalgia have high levels of oxalates.

Oxalate affects nerves, causing neurological symptoms as well.

It is a magnet for some minerals, it has high affinity to Ca, iron, Zn, phosphate and it takes these minerals out of the body, especially calcium.

Before eliminated by the kidneys, oxalate goes through many organs causing problems. It is damaging the urinary tact, might cause chronic UTI, interstitial cystitis (with no bacteria), bladder infection or vulvar pain (vulvodynia).

Oxalate can affect the sphincters of the stomach causing acid reflux and GERD symptoms.

It can play a role in autism, in different skin conditions, liver disease, peptic ulcers and Crohn’s disease.

Oxalate nanocrystals can get into the cells and influencing certain intracellular processes and enzyme functions. They damage the mitochondria, cause mitochondrial dysfunction, which can lead to almost any chronic disease.

Patterns of symptoms associated with oxalate toxicity

If you ever had kidney stones or have two or more of the following symptoms, you might benefit from a low oxalate diet.

  • kidney infection

  • chronic gastrointestinal problems

  • chronic pain without obvious reason

  • difficult or not full recovery from injury

  • chronic stiff muscles

  • fatigue, restless sleep

  • recurring UTIs

  • brain fog, mental fatigue

Absorption of oxalate

Soluble forms of oxalate are absorbed and trigger inflammation, causing different health issues, such as nerve damage, pain, fatigue (cell death) and cell dysfunction. The absorption rate varies between people. Those with leaky gut absorb more of it as there is a free pass through the gut lining. Leaky gut is a very common condition today.

Higher levels of oxalate are made by the body when someone is

  • deficient in vitamins B1 or B6

  • taking a high amount of vitamin C

  • has dysbiosis of intestinal bacteria and fungal overgrowth

Others with a history of antibiotic use, lack of oxalate-degrading bacteria and thus will have higher levels of oxalate. Glyphosate exposure kills the gut microbiota, causing more absorption of oxalate as well.

Prevention of absorbing oxalates

There are a few products that are protective against oxalate, such as dietary calcium, magnesium, potassium and dairy.

Many people don’t eat dairy and replace it with very high oxalate foods, such as almond milk or other nut milks. These processed foods can cause even more health problems than dairy itself.

Seasonal eating is another thing that can be protective. It is important because it gives the body time to get rid of different plant toxins.

It is important to remember that oxalate damage is a toxicity problem, it is not an allergy or sensitivity.

It is worth to mention that there is also a genetic condition called primary hyperoxaluria when the excessive endogenous oxalate can deposit in any tissue in the body and cause serious health problems.

Elimination of oxalates

If you eat a high oxalate diet and have any of the health issues mentioned above, you need to consider starting a low oxalate diet. It is very important reducing your oxalate intake gradually.

When you eat a high oxalate diet, the blood is full of it and it gets stored in the tissues. In this case, the tissues cannot get rid of accumulated oxalates.

If you stop eating these foods suddenly, blood level of oxalate goes down which is sensed by the tissues. After a certain time, they start to release the stored oxalate into the blood to get rid of it - this is oxalate dumping.

So, when the tissues release oxalate into the blood, you get symptoms. This is the way to get rid of oxalates but it can take a long time. Oxalate comes out via the kidneys, gut, skin, mouth and eyes.

On a low oxalate diet, people feel suddenly better but different symptoms can occur and get worse as oxalate dumping happens

Foods low in oxalate

Meats, dairy, eggs, fats, oils and other non-plant foods are naturally low in oxalate.

There are also plant foods that are low in oxalate, such as cabbage, broccoli, lettuce, salad greens, arugula, avocado, bok choy, green peas, garlic, cucumber and winter squash for example. However, they might contain other plant toxins.

Tolerance for oxalates differ between people depending on their health conditions. For healthy people it takes time to accumulate toxic levels and they can get rid of it better. However only small amounts of oxalate can be very problematic for diseased people.

The liver is detoxifying the body of via different pathways but it does not have the capacity to detoxifying oxalates. Oxalate cannot be conjugated to any compound to be eliminated. It can take years to get rid of it but it is important for you have to remain with the low oxalate diet.

The best diet you can follow is the Paleolithic-Ketogenic Diet (PKD). It will fix your health problems, including those which are caused by oxalates. For some people it only takes a few weeks but for others it can take much longer, depending on their health condition, how sick they are and how long they have been ill. If you are on PKD, no dietary supplements are recommended. The finely-tuned diet with professional support will lead to recovery.

On the other hand, if you don't follow the strict version of PKD in the right way, there are still some things you can do to get better. You can support the oxalate dumping by consuming foods rich in calcium or charcoal before eating. Taking magnesium, potassium or calcium, all in a citrate form and vitamin B supplements are also recommended. KetoCitra® is an excellent product that contains Beta-Hydroxybutyrate (BHB), Citrate, Alkaline Base, Potassium, Calcium and Magnesium .

Epsom salt bath can be helpful as well as topical use of DMSO. These relieve the oxalate induced pain.



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