Interstitial Cystitis, Protocols

Oxalates and Interstitial Cystitis

Oxalates are the salt form of oxalic acid, an acid that is found in many plant foods and can also be produced in the body.

Oxalic acid can form oxalate crystals when binding to minerals such as calcium. When deposited in the body, these can cause a lot of pain, similar to tiny glass shards.

This is probably most well-known with regards to kidney stones, which can often be oxalate/calcium stones.

There is also some evidence that excess oxalates could play a role in painful bladder conditions, such as interstitial cystitis. However, this evidence is more anecdotal than based on scientific studies (as there haven’t been any studies that I know of). Today I would like to look at some potential connections between oxalates and interstitial cystitis.

I don’t believe that there is one single cause to so-called ‘interstitial cystitis’, which is why I try to look at the different possibilities. I had heard about the potential of high-oxalate foods before, but oxalates recently peaked my interest when some of my own test results showed high oxalic acid levels. Not much later, I also spoke to a client whose urinary symptoms seemed to get worse when high-oxalate foods were consumed.

Oxalates and the Urinary Tract

Oxalates can form in the kidneys, as well as the bladder and ureter. If they grow big enough, they become kidney stones and can cause a lot of pain.

But even small crystals have the potential of causing pain. Some of these crystals can have very sharp ends.

The shape of oxalate crystals somewhat depends on which mineral they bind to. Calcium stones for example can look like little stars or even corals. Zinc crystals can look like little discs with very sharp edges.

Oxalate stones seem to be more common in the kidneys and therefore, there seems to be a chance of high oxalates affecting the urinary tract.

Now what would happen if smaller crystals were present in high amounts in the urinary tract, without being full-blown kidney stones? Well they might just have the potential to cause some pain and potentially damage.

Conditions that are associated with Oxalates

There are several conditions in which oxalates may play a role, including autism, ME and fibromyalgia.

One of the conditions that is often tied to bladder problems is vulvodynia, which manifests as pain in and outside of the vagina. Some theorize that this pain comes from oxalate crystals depositing in the vaginal tissue.

I have spoken to a few ‘IC’ sufferers who were also experiencing these type of symptoms.

Where do Oxalates come from?

There are a few reasons oxalates may be high in the body. The following are the main sources of oxalates:

  1. Production in the liver: a breakdown product of carbohydrates, fats and protein, called glyoxal, can be converted into oxalate. This conversion may be increased with oxidative stress. There are also genetic mutations that increase the risk of oxalate formation in the body.
  2. Food: Oxalic acid is found in a lot of plant-based foods and a high intake of these foods can contribute to the oxalate burden. Some of the worst offenders are spinach, rhubarb, almonds, soy and potatoes.
  3. Yeasts: different yeast species can produce high amounts of oxalate crystals. Therefore, yeast overgrowth in the intestinal tract can be one of the main reasons of elevated oxalates. I have seen this combination in clients and myself.

How to know if you have an Oxalate issue

The best way to identify this is by doing the Organic Acids Test (Great Plains Lab). This test not only shows if oxalates are elevated, it also shows markers for yeast overgrowth, as well as the potential for genetic mutations affecting oxalate production.

The next best way would be to see if high oxalate foods (see below) make bladder symptoms flare.

And lastly one could look for other symptoms associated with high oxalates (but be beware that these are non-specific, meaning they could be due to something else).

These include:

  • Tendency to kidney stones
  • Cloudy, smelly urine
  • Urine that drops rather than flows, frequent small urinations
  • Popping and/or cracking joints
  • Sensitive skin, skin burns easily
  • Crawling or tingling feeling on the skin
  • Tingling extremities
  • Inflammation
  • Sores and/or bumps
  • Stabbing or stinging pains
  • Clitoral pain
  • Painful intercourse
  • Irritable bowel and/or bladder
  • Tinnitus
  • Insomnia
  • Muscle pain and cramps
  • Grainy stools

What to do about Oxalate Issues

The first thing to do, no matter the reason for high oxalates, would be to reduce foods high in oxalates. Now we don’t need to avoid all foods with oxalates (as this is nearly impossible) but ideally reduce the highest offenders.

Cooking food in water and then discarding the cooking water may get rid of some oxalates. Additionally, one could add calcium or magnesium citrate to the cooking water, which have the ability to bind to oxalates.

Taking magnesium citrate (max 300 mg/daily) with a meal high in oxalates can help reduce oxalate absorption, as magnesium can bind to oxalates so that they can be excreted through stool. The citrate also competes with oxalates for absorption and as such can act as a ‘second-line of defence’.

In the US, there is an oxalate-reducing enzyme available (called Nephure), which could be helpful.

If there is a yeast overgrowth issue, then reducing yeasts with antifungals is an important step.

Beneficial bacteria such as Bifidobacteria and Lactobacilli can help degrade oxalates, so a beneficial bacteria supplement may also be helpful.

One of the most important gut bacteria for oxalate degradation is Oxalobacter formigenes, a bacteria that is easily destroyed by antibiotics. Unfortunately there are no supplements containing this bacteria available at the moment, but one company is working on it.

In people with fat maldigestion, unabsorbed fats can bind to calcium and in turn increase oxalate absorption. Liver and bile support (e.g. bitters, milk thistle extract, taurine, lemon juice and olive oil) may help support fat digestion.

Sufficient vitamin B6 is needed for oxalate degradation and therefore supplementation may be helpful. The organic acids test also tests for B6 levels, so the need for this can be seen on the test results.

Interestingly, the IC medication Elmiron may decrease the crystal size of oxalates, which could be one reason it helps some people.

Foods Highest in Oxalates

As I said above, there’s no need to limit every food with oxalates as this would be extremely restrictive! But it may be a good idea to reduce the highest offenders (per portion):

  • Spinach (both raw and cooked)
  • Rhubarb
  • Bran (especially rice)
  • Buckwheat
  • Almonds
  • Miso
  • Wheat
  • Potatoes
  • Soy
  • Navy beans
  • Beetroot
  • Cocoa, chocolate
  • Brown rice flour
  • Cornmeal
  • Millet
  • Okra
  • Cashews
  • Raspberries
  • Dates

Bear in mind that these lists vary and it’s hard to know which one is right. I’ve tried looking for a reputable list.

A word of caution on Vitamin C and Gelatine

Vitamin C and gelatine (or collagen, or bone broth) are supplements/foods that I often recommend. However, in case of oxalate issues we need to be careful with those.

Ascorbate (vitamin C) can be converted to oxalates if taken in high doses but this seems to be an issue with ascorbate metabolism and is not necessarily the same for everyone. Therefore, I don’t recommend people with oxalate issues take more than 4 gram daily.

Glycine, found in bone broth, gelatine and collagen can also be converted into oxalates and therefore people with oxalate issues may need to limit these (any mineral supplements of the ‘glycinate’ form are the same).

As always it’s a good idea to work on these issues with a knowledgeable practitioner.

Have you noticed oxalate foods giving you issues? Let me know your experience in the comments!

Pin it for later:


The University of Chicago How to Eat a Low Oxalate diet accessed July 2018

Bonovich, Jessica Oxalates Great Plains Laboratory Aug 2016

Low Oxalate diet

Vulval Pain Society The low-oxalate diet accessed July 2018

PK Diet The Oxalates & Salicylates Foods Lists accessed July 2018

Shaw, William The Role of Oxalates in Autism and Chronic Disorders Wise Traditions in Food, Farming and the Healing Arts WAPF Spring 2010

The VP Foundation Symptoms of VP (Vulvar Pain) Syndrome accessed July 2018


  • Reply


    July 31, 2018

    Very interesting and informative article, Layla. Also you made it easy to understand so thanks!

  • Reply


    August 10, 2018

    That’s really interesting and good to know. I didn’t know you could do Organic Acid Test, something that I definitely want to do in the future, thanks for sharing!

    • Reply


      August 10, 2018

      The organic acid test is great, best test I have done so far – gave me tons of insight!

  • Reply

    Georgette Griglia

    March 16, 2019

    is there anyone with ic that live in Pgh Pa or beaver Pa

  • Reply


    March 9, 2020

    Layla thanks a ton for this information
    I recently was trying to get into raw eating and juicing and for 3 days I had spinach juice empty stomach in the morning and beetroot juice in the evening and had stopped dairy completely.
    And on the 3rd day I had a UTI …. I have had UTIs in the past but this one came after an year and a half that too when I was trying to eat healthy .
    After reading ur article I realised may be oxalic acid from spinach and beetroot caused it !

  • Reply


    March 9, 2020

    Thanks a lot Layla for this highly valuable information
    I was trying to eat vegan (had left dairy a month ago) because of my stomach issues and started having spinach + cucumber juice in morning on the 3rd day of this high spinach (raw) diet I got a UTI
    I have had UTIs in the past but this one came after an interval of 1 and a half year .
    I now know what must be the reason.
    Thankyou .

  • Reply

    Michael Mathieu

    March 19, 2020

    Thanks for this article!

    Sally K Norton is one of the experts on oxalates. Her website has lots of great information and she has a decent reputable list of foods high in oxalates and low in oxalates. If you work with her directly she will sell you her more in depth version. She has lots of great videos on YouTube.

    Susan Owens is another expert and she runs the Facebook page called trying low oxalate’s. they have a sub group that allows you to download their spreadsheet on oxalates which is also highly reputable.

    A tricky thing with the organic acid test is some research was done in which on a given day they collected all of the participants urine output. What they found is that most people only spike oxalates during one or two of their voids during the day. So if you collect a urine for the organic acid test you may or may not catch any oxalates. That happened to Sally K Norton. She did the test and thought she didn’t have an oxalate problem, but it turned out her problem was serious.

    • Reply


      March 23, 2020

      Thanks for sharing this! The OAT test does specify to use the first urine in the morning, which presumably would be very concentrated but this is interesting to know and worth bearing in mind if one has all the symptoms despite negative test results!

  • Reply

    Peg Winsor

    April 17, 2020

    Thanks for the good information, Layla. I am wondering, is there a way I can still take the OAT test when I am wildly intolerant to lactose, which is part of the formula for the galactose substrate? Thanks in advance.

    • Reply


      April 19, 2020

      The OAT test only requires a urine sample, you don’t need to ingest anything (you might be thinking of the SIBO breath test ?).

  • Reply

    Chris Bronson

    November 17, 2020

    Thank you. Oxalates are of huge interest and importance to celiacs. Healthy guts absorb about 1% of dietary oxalates. Celiacs can absorb as much as 40 to 50% of dietary oxalates. Our bodies are able to excrete a certain amount of oxalates daily, typically through urine (but it is also possible to excrete them in the stool). When we exceed the amount our bodies can excrete, oxalates are stored in our tissues. They have been found in every tissue in the body. They can be extremely toxic. Oxalates are known to induce further food toxicities. For celiacs, this is extremely problematic. It may be the reason why celiacs find that, with time, they become intolerant to a wide range of foods, such as other grains (notably corn), dairy, egg, soy, and so on. Oxalates are also thought to be a contributing factor to osteoporosis, presumably because they bind so readily to calcium and magnesium.

    Celiacs make too much zonulin in the gut, which regulates absorption of macromolecules. Anything that exacerbates leaky gut (GMOs, pesticides) can presumably affect oxalate absorption. How much this is a factor for non-celiacs is unknown but of considerable concern.

    Unfortunately, there is no way of testing for oxalates in body tissues, which would be ideal. A serum test exists but is not readily available. Urine testing is readily available but can be very misleading. (High urinary oxalates suggests a problem. Low or normal urinary oxalates does not in any way exclude a problem, which is illustrated in one of the comments above.)

    Detoxing from oxalates is relatively simple since oxalates leave the body easily (as long as dietary intake is reduced) but it should be done slowly and carefully, under the supervision of a knowledgable physician. This is because oxalates are potent chelators (binders) and they bind to bivalent cations (calcium, magnesium, zinc; also potassium) which can become rapidly (dangerously) depleted. It is possible to be very symptomatic while detoxing. I have had experiences with patients being suicidal and being tachycardic (heart rates up to 200 bpm).

    Please consult a quantitative list of oxalates in food, such as the one put out by the T.H. Chan School of Medicine. It is helpful to count oxalates as you might count calories. Lists that refer only to low, moderate and high levels of oxalates are very misleading. A few foods are so high in oxalates (chocolate, spinach, rhubarb) that they should not be ingested at all on a low oxalate diet.

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