What Are Oxalates?

When someone is first introduced to the concept of oxalates, they often have never heard of them before. Here I will present both a literal and a functional definition for oxalates; i.e. what they are and where they come from, as well as what that means for someone attempting a low oxalate diet.

A Literal Definition

Oxalate ball and stick model

A ball-and-stick model of the basic oxalate molecule.

The term “oxalates” is a broad descriptor for several related substances. The basic molecule called “oxalate” is comprised of two carbon atoms and four oxygen atoms, commonly written as C2O42-. This is a negatively-charged molecule which bonds readily with any number of positively-charged molecules or atoms; hydrogen is a common one, and results in the formation of oxalic acid. Thus, any substance so combined with an oxalate molecule could correctly be termed an oxalate.

Oxalates, both in the form of oxalic acid and other forms, are commonly found in nearly all plant foods. Spinach, sorrel and rhubarb are commonly-known high oxalate foods. Oxalates are present in plants because they are a product of the incomplete oxidation of carbohydrates.

A Functional Definition

As mentioned above, oxalates are very common in plant foods. They may also be found in smaller amounts in eggs, meat and dairy. Simply put, oxalates are a component of all food. In practice, this means it is impossible to completely avoid oxalates, and still consume a nutritious diet. However, as the low oxalate diet aims to demonstrate, it is certainly possible to keep the amount of oxalates consumed in the food to a minimum, and still eat healthfully.

In addition, the body is capable of converting other substances into oxalates. For example, if a person consumes more Vitamin C than their body needs, the excess ascorbic acid is often converted to oxalic acid. This is one of the hidden hazards of the common practice of taking megadoses of Vitamin C (reference here).

What may be more important are the ways that oxalates are stored in the body. For example, while we know that kidney stones are often formed from calcium oxalate, we do not yet know how much of this type of kidney stone formation is caused by genetics, how much is diet, and how much is caused by other factors such as medication side effects and interactions. So while a kidney stone diet often involves lowering oxalates, we do not yet have the long-term studies needed to see how much of a reduction in kidney stones such a diet can cause.

Similarly, the other effects oxalates have within the body are still fairly poorly understood. Researchers are just beginning to understand that kidney stones are merely the tip of the iceberg in terms of the consequences of the body storing oxalates. For example, oxalates, once stored in cells, can interfere with mitochondrial function. Mitochondria are considered the “powerplants” of cells, and are thus essential to every basic life function. Without proper mitochondrial function, cells will starve due to a lack of energy. This makes it easy to see why we observe oxalates interfering with an astounding number of physical and cognitive functions.

Therefore, functionally speaking, oxalates are toxins. Toxins, if you will recall, are naturally-derived poisonous substances. While “poisonous” might at first seem too harsh a term, I would beg to differ. Once you consider that oxalates are capable of causing cell death, I’m sure you’ll agree that they are, in fact, toxic.

Of course, the body has some ways of dealing with oxalates; we already know they are also excreted in the feces and urine, and it has been hypothesized that the body knowingly stores oxalates in cells in an effort to take them out of circulation in the bloodstream. While it is comforting to know that the body has ways of sequestering and excreting oxalates, one must remember that, as with almost every other substance, “the devil is in the dose.” In small quantities such as what are found in meats and low oxalate vegetables, I have no doubt that a healthy, well-functioning body would have no difficulty ridding itself of excess oxalates. However, once you begin to expose the body to exponentially higher levels of oxalates in food, it will understandably have more difficulty clearing these toxic substances out. Adding in some of the sneaky side-doors oxalates have for entering the system, such as through a damaged or “leaky” gut, and intravenous Vitamin C, and you can see where a full-blown oxalate toxicity problem could develop quite rapidly, given the correct conditions.

So, What Are Oxalates?

As you can see, oxalates are in some respects very easy to define, at least in terms of their chemical structure. However, if you wish to consider the broader definition of oxalates, in terms of the effects they have on the human body, there is much yet to be learned. It is my sincere hope that if you have an oxalate problem, you will consider joining us at the Trying Low Oxalates Yahoo Group, and learn as much as possible about how to both clear these toxins from your system and mitigate their negative effects.

4 Responses to What Are Oxalates?

  1. shane calma says:

    hi., may we know if i have a low in oxalate or in purine? thanks

    • Michelle Fields says:

      Hi Shane,

      I’m sorry, but I don’t quite understand your question. Could you maybe rephrase?


  2. Kim Davis says:

    It seems that some members of the population, like those with autism, seem to have more trouble with oxalates and/or are more sensitive to them. Is there something that can be done to reduce this sensitivity or enable the body to more effectively excrete oxalates?

    • Michelle Fields says:

      Hi Kim,

      From what I’ve seen and read, the low oxalate diet seems to be the most effective method for allowing the body to excrete oxalates that we currently know of. This reduces the oxalate burden on the body, and allows it to “dump” the oxalates stored in tissues. See my page on the effects of oxalate dumping for more information about that phenomenon.

      One other hopeful therapy is probiotics, although there is still a TON of research that needs to be done to determine both which strains can effectively colonize the gut, as well as which strains do the best job of breaking down oxalates. You can see my brief overview of some of the probiotics recommended on the Trying Low Oxalates group here.

      With probiotics, as with other treatments, there’s also the whole money issue. For example, we know that OxThera is trying to bring to market (in the US) a strain of Oxalobacter Formigenes, which is known to degrade oxalate. However, because they are trying to do this as a drug (rather than an over-the-counter probiotic), they are still mired in the testing phases of the FDA. So it may be years before we know whether this is an effective treatment.

      On the bright side, if they can prove efficacy, it will be good to know that the money you spend on the product is not going to waste. On the down side, this option being brought to market as a treatment for hyperoxaluria (or even primary hyperoxaluria) will severely limit the number of people who have access to it.

      Last but not least, avoiding antibiotics (which have been shown over and over to wipe out those gut bacteria species which *do* have oxalate-degrading capabilities) in all but the most dire of circumstances is advisable. My own husband recently learned this the hard way, taking the same antibiotics that caused me to need the LOD. Lucky for him, I knew why he suddenly started getting headaches and leg cramps after his course of antibiotics, and was able to adjust his diet and supplements rapidly. But how many people suffer needlessly because docs are still prescribing these things willy-nilly?

      Hope this helps,

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