Where Do We Get Oxalates From

April 17, 2022

Where Are We Exposed to Oxalates?

Last week we learned that oxalates have no role in humans except as a breakdown product of two amino acids. We make about 25 mg a day. Plants, however, use oxalates widely, mostly as poisons to keep themselves from being eaten by other creatures like insects, etc. And, oxalates allow plants to live in adverse environments with high burdens of toxic metals. Oxalates bind and chelate many heavy metals.

We also learned that it is possible for humans to die from oxalate poisoning. There are rare but famous examples of folks who have eaten rhubarb leaves. The toxic, pre-lethal dose is considered to be 500 mg/meter squared body surface area. That appears to be a lot and there is quite a bit of space between the 25 mg a day our body makes and excretes, and the lethal dose. Or is there?

Just about every health website has a page listing high oxalate foods and admonitions to be cautious if you have kidney stones. WebMD has a nice page listing spinach where a half cup of cooked spinach will give you 750 mg of oxalates. One cup of soy milk, or soy yogurt will give you 336 mg. One ounce of almonds gives you 122 mg. Baked potato, 97 mg. Beets, 152 mg per cup. Beans, 76 mg. How about a nice, "healthy" smooth cleanse? Well, put in a couple of cups of spinach in your smoothie, add some soy, some nuts and you could have yourself a lovely oxalate rush. If you had gastric bypass, a known method to induce higher oxalates, and got yourself a smoothie cleanse, you could go into renal failure, and end up on dialysis, as proven by one case report

Is all this exposure a problem? Well, yes! Here is one example. Did you know that you can show a link between oxalate exposure and the calcifications in breasts that are the early sign of breast cancer in women? And if you then inject oxalate into mouse footpads, a common method of measuring toxicity, you can demonstrate the growth of cancers that appear similar to breast cancer in humans.

Another example. Folks with decreasing kidney function are known to have high oxalates in their urine. Recent research has shown that there is marked activation of the inflammasome pathway of progressive inflammation linked to oxalates.

What happens if we eat foods high in oxalates? Well, research has been done on that. Let's take the iconic wonder food, chocolate. It's pretty high in oxalates. Take 6 volunteers and have them eat 100 grams of chocolate. That's quite a lot, but a goal most of us can stretch to reach. That dose of chocolate will raise your blood level of oxalates to the same level as someone with the genetic defect, primary oxaluria. Voila, you have made yourself potentially ill for a couple of hours. Now, do that every day.

Just about every oxalate website out there says the nutritional quality of high oxalate foods balances out the risk of the oxalates, which become high risk only rarely. Paul Saladino, in his book, The Carnivore Code, says you are playing with fire. Bruce Ames explains how in his "triage theory" that posits the short-term effects of mild deficiency, or excess is not noticed. Only severe deficiency becomes apparent in the short term. But long-term, low-grade deficiency, or excess wears you down. "Death by a thousand cuts." Oxalates are little tiny cuts. And we expose ourselves to them at our own risk.

www.What will Work for me. I really wanted to learn about oxalates and internalize the details. It's the gradual decline in kidney function that I see in so many people who are essentially vegans that I worry about. The number of women with mammograms showing microcalcification, and who are heavy plant-eaters.... All of these examples haven't really been studied as the long-term effects are too expensive a research project to do. I am an "n" on only one. I'm not a randomized controlled trial by myself. I don't have medical research to guide me. But I eat a lot of vegetables, spinach included. I love "saag paneer", Indian spinach curry. I have it about once a month. Bruce Ames is suggesting that the "long game" of long-term health is an important consideration. There are some plants that are low oxalate that I love. Hurray for black and blueberries (raspberries are pretty high). Kale is low. Ditch the spinach. (WebMD has a nice list of Low Oxalate Foods...many sites do too)

References: Am Jr Kidney Disease, BMC Cancer, Curr Opin Nephr Hyper, Nephron,  Am Jr Clinical Nutr, Nature, Carnivore Code,

Pop Quiz

1. What food might be the highest oxalate food? Name a couple: Answer: spinach, almonds, soy, potatoes, raspberries, chocolate

2. What percent of Americans have kidney stones? Answer: Somewhere around 7-10%. Most of them are oxalate-based.

3. What percent of American women have microcalcifications on mammogram? Answer: Somewhere around 10-15%

4. How much oxalate does my body make every day? Answer: 25 mg.

5. And how much oxalate can I get from a green smoothie with spinach in it? Answer: Ooooh! Ten times your minimum. Same with 100 grams of chocolate.