It seems ironic that oxalates can be found mostly in what we would term as healthy foods: spinach, rhubarb, swiss chard, beet greens, almond/flour, soy, cacao, okra, chia seeds, black raspberries, star fruit, sweet potato, and others. But I guess these healthy foods are smart foods, since oxalates are their natural defense mechanism to protect them from predators, including human predators! If you have been unknowingly (or knowingly) consuming these foods in excess, you may have been also noticing strange symptoms throughout your body. In this article, I will discuss what oxalates are, where they come from, where they’re going, and if they could be the root cause of your pain.
We do not need to only worry about the oxalates in food we consume — our liver also produces oxalates as a byproduct, from a non-essential amino acid called hydroxyproline, that is derived primarily from collagen. That is the same collagen made up of protein, and that we consume in our diets. Those who are consuming excess animal products, collagen and gelatin powder, should also be aware. That hydroxyproline, which when broken down, may produce endogenous oxalates that may exceed even your exogenous oxalate intake.
And there are other things that may contribute to the buildup of high oxalate production in the body — most notably, ascorbic acid, from vitamin C supplementation.
Oxalates come from an acid, oxalic acid, that binds to minerals. So oxalates are oxalic acid combined with mineral(s). Oxalic acids chelate to minerals, and may deplete these minerals from our body. The most famous chelated mineral is calcium. But oxalic acid chelates other minerals, such as magnesium, sodium, and potassium. Calcium oxalates are famous because they are the most abundant and hardest form of oxalates and are most associated with kidney stones.
In fact, oxalates can be harder than tooth enamel and dentin — this is the case, specifically with calcium oxalates. When these oxalates accumulate and bond together, they form hard crystals, described as “razor-sharp edges” or “tiny shards of glass”, i.e., when examined under a microscope. This explains why having kidney stones is such a painful experience.
Types of oxalates
Oxalates exist in both soluble and insoluble forms. Generally speaking, sodium oxalates and potassium oxalates are considered soluble, while calcium oxalates and magnesium oxalates are considered insoluble. Soluble and insoluble are exactly what they sound like: soluble oxalates dissolve in water, and can thus travel around in blood easily. Insoluble oxalates do not dissolve, and are more susceptible (precipitate) to form stationary crystals. However, in the case of magnesium oxalates, it may share characteristics close to soluble oxalates.
A convenient way to guess whether or not a food-source is (mostly) soluble oxalates is simple: if it is plant leaves, it is most likely soluble. If it carries a high water content, that may be another clue it contains mostly soluble oxalates. Young, tender plant leaves often accumulate potassium salts (soluble). Root vegetables and seeds, on the other hand, often contain more calcium oxalate crystals, which are insoluble.
What happens when we consume high oxalate foods?
If it’s soluble, oxalates will readily absorb through the intestinal lining into the bloodstream. If insoluble, it should stay within the digestive system for excretion, unless the gut is compromised — such as the case with leaky gut.
If the microbiome in the gut is properly maintained, bacteria will help break down oxalates and use them as a source of energy. This is particularly and specifically the case with a certain bacteria called: oxalobacter formigenes.
If there is excessive oxalates coming in, more than the kidneys can process, a build up of oxalates, especially insoluble calcium oxalates may form in the kidneys, eventually leading to painful kidney stones.
As high as 50-60% of soluble oxalate from food can be absorbed if no mineral binding occurs. Less than 5% (typically 1-2%) of insoluble oxalates is absorbed through the gut. The greater the gut dysfunction rate, the greater the insoluble oxalate rate of absorption.
Which is worse, insoluble or soluble oxalates?
While insoluble oxalates, such as calcium and magnesium oxalates generally reside in the gastrointestinal region and can ideally be excreted, soluble oxalates made of potassium and sodium can travel throughout the bloodstream. These soluble oxalates are not particularly concerning, since they don’t form hard crystals like calcium oxalates do. However, once in the bloodstream, these soluble oxalates can be hijacked by calcium ions and then turn into insoluble oxalates! These oxalates can then wreak havoc and settle everywhere throughout organs and tissues in the body in crystalized form.
So to answer the question which is more dangerous, soluble or insoluble oxalates(?):
- Insoluble oxalates are generally considered more dangerous if they are not being excreted, since they form hard crystals.
- But soluble oxalates can also be dangerous since they travel to more locations and can be hijacked by calcium ions to become insoluble oxalates.
So now you may have pain in the joints that may resemble classical arthritis. Now there might be skin rashes and itching. Now you may have muscle ache or fibromyalgia-like symptoms. Now you may have pain in the eyeballs and impairment of vision. Now you may have pain in the vagina (vulvodynia) and not know why. Now you may have stomach bloat and other digestive issues resembling IBS. Now there may be severe mineral and vitamin deficiency throughout the body. There may be fatigue and irritability. And of course, there may be the classical symptoms that oxalates are associated with: kidney stones and kidney dysfunction.
What causes oxalates to build up in the body?
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High dose vitamin D may increase calcium buildup up, thus calcium oxalate build up
– Taking excess ascorbic acid — though considered an antioxidant — may act as an oxidant when small proportion is metabolized in the liver, forming oxalic acid
– Consuming foods high in oxalates, especially without properly boiling and rinsing them may cause exogenous oxalate build up. These include: spinach, rhubarb, swiss chard, beet greens, almond/flour, soy, cacao, okra, chia seeds, black raspberries, star fruit, sweet potato, potato, cashew, and peanut. Even some herbs are high in oxalates, like turmeric, milk thistle and black elderberry extract!
– A low fiber diet will lack the necessary microbiota to degrade oxalates, most notably a lack of the bacteria oxalobacter formigenes.
– Excess use of antibiotics will disrupt the microbiota.
– A high-protein diet, particularly one rich in animal protein, can increase oxalate levels because the amino acid hydroxyproline, found in collagen, is metabolized into oxalates in the liver.
– Certain genetic disorders, such as primary hyperoxaluria, may predispose someone to building excess levels of oxalates.
How to prevent oxalosis (i.e., the buildup of oxalate crystals in the blood and body):
– See above ⬆️: [What causes oxalates to build up in the body?]
Congratulations — you have decided to decrease oxalates from your diet and expel the excess from your body! There is a problem though. It is colloquially called “oxalate dumping”. If you suddenly decrease oxalates from your diet, you may have withdrawal symptoms. Typically, our kidneys only excrete 50 mg of oxalates per day. However, if your prior intake was much more and you suddenly stop, there may be excess oxalate dumping, that may be traumatic to the kidneys. This is especially true if you add things to expel oxalates from your body. It is therefore advised you thread slowly in the effort to rid excess oxalates from your diet and from your body.
– To maintain proper oxalate levels, your vitamin B1 and B6 levels must be sufficient, to increase proper liver function and metabolism of endogenous oxalates
– Consuming lemon water will increase citric acid, which may bind to calcium in the urine — forming soluble calcium-citrate complexes instead of insoluble calcium-oxalate crystals and their aggregation
– Consuming certain herbs may help dissolve or break up oxalates: namely, chanca piedra, sambong and corn silk
– Avoiding the highest oxalate foods completely should be considered: especially spinach, rhubarb, swiss chard, almond, soy and star fruit.
– Avoid consuming excess animal products, collagen and gelatin powder, which may cause your liver to produce excess endogenous oxalates
– Consider increasing your
magnesium intake since magnesium oxalates, though technically an insoluble oxalate, may be less insoluble than calcium oxalates, helping to move and excrete excess out of the body
