High Oxalate Foods: Why They’re Problematic

Oxalates are chemical compounds found in many plant-based foods. While they are toxic antinutrients, most people don’t realize how problematic they can be.

I was wrong.

I thought I was eating a very healthy diet. I was eating plenty of fresh fruits and vegetables, lots of nuts and seeds, and yet, each day I was drifting further and further into a brain fog that I couldn’t escape from. 

When it was time to work on the blog, I would sit down at the computer having no idea what to write. Sometimes I did but just felt too fatigued to do so. On a good day, I was able to make and film a new recipe, but by the time I wanted to share it, I had no idea how to put it together and publish it, despite years of experience doing so without issues. 

As my diet got “healthier”, I felt worse. I felt like the hours in the day were shrinking and I just couldn’t get anything done. Ever.

My carnivore diet experiment

On a whim, one day, I decided to try the carnivore diet. It seemed a bit crazy to me, but I had seen several good testimonies on YouTube and figured, “Why not?” I wasn’t feeling well and was getting desperate.

On September 28, 2022, rather than have my usual breakfast of matcha in coconut or almond milk, filled with chia seeds for satiety, I chose to eat eggs, bacon, and meat! Rather than snack on celery and almond butter, I chose pemican or pork rinds. Dinner was no longer a plate full of veggies or leafy greens, sometimes accompanied by a bit of fish. Instead, I chose a big, fatty, juicy steak. 

After a day or two, I already felt amazing. My energy started to rise, and I didn’t feel quite as foggy. My skin was clearing up; not only the eczema on my right ankle but also the acne on my face. I was sleeping better and had a better attitude in general. My nails were getting stronger, and I was looking and feeling healthier than ever.

Until…things started to take a turn for the worse…

Oxalate dumping

About two weeks later I experienced something that I later found to be oxalate dumping symptoms.

Urinary tract infection symptoms

One evening, I started getting familiar symptoms of a urinary tract infection coming on. For a while in the past, I was getting them almost monthly. I ran for the d-mannose, and the symptoms mostly went away, but I continued to have cloudy urine, on and off, for several weeks. 

Hives/rashes

A month into my experiment, I broke out into very itchy hives. As much as I generally try to avoid medications, it got so bad that I had to turn to an antihistamine and corticosteroid cream for several days. The rash coincidentally started two days after my husband had a reaction to a bad mussel from a batch we ate at a restaurant. Everyone just assumed I was reacting to bad seafood, but I wasn’t so sure. (I hadn’t had any sort of digestive symptoms and the timing seemed off.)

While they cleared to a tolerable level within about a week, I continued with a rash all over my arms and back for several weeks longer. I also got cycles of cloudy urine, an occasional pimple, and a bump or two of eczema all at the same time. I also had red, irritated skin on my face and red, dry eyes.

• 

• 

• 

Oxalate dumping symptoms

Being new to the carnivore diet, I was doing a lot of investigation on the topic. I found that many new carnivores were experiencing what they called oxalate dumping.

Oxalate dumping occurs when a person stops consuming high-oxalate foods after having consumed them over a long period of time. As the concentration of oxalates in the body goes down, the body works to rid itself of the oxalates that have built up and been stored in the body.

Oxalate dumping happens to a lot of people who begin the carnivore diet because animal foods are generally extremely low in oxalates. (The exception is bone broth and gelatin because oxalates can accumulate in animals’ connective tissues.) When one makes a drastic change from a high oxalate diet to a very low one, it can bring on drastic symptoms.

Some oxalate dumping symptoms include hives, rashes, acne, cloudy urine, and joint pain. Sound familiar?

What are oxalates?

Oxalates are a type of naturally occurring chemical found especially in many plant-based foods. They help plants defend themselves against insects and other predators (like us). When one eats too many oxalates at once, they can build up and cause numerous adverse health effects.

What problems do they cause?

High oxalate levels can cause a wide range of symptoms and health problems that range from mild to severe. They can cause inflammation, joint pain (arthritis, carpal tunnel syndrome), skin irritation (eczema and acne), kidney stones, and other urinary tract problems like UTIs. They can also lead to digestive issues, brain fog, and fatigue. 

Oxalates are chelators that can prevent your body from properly absorbing minerals, such as calcium. They may even leech calcium from your bones which weakens your bones. The oxalate binds with calcium to form calcium oxalate crystals that can accumulate in joints causing arthritic-like symptoms of oxalate “gout”. 

Why is excess oxalate stored in the body?

It seems strange that the body would want to store toxic substances like oxalates within the body. The body can only eliminate a certain amount at once, though, without causing serious damage to organs like the kidneys. If one eats a low-oxalate diet, the oxalates are eliminated immediately after their intake, mostly through urine. On the other hand, if one eats a high-oxalate diet, the body stores the extra until it is able to process and eliminate them.

If you continue a high intake of oxalates, your body will continue to store the excess. You may start to notice more and more symptoms. Most people don’t attribute those symptoms to their high-oxalate diet, though, thinking they are eating in a healthy way.

In fact, they, like me, may not realize those oxalates were a problem until they make a switch to a low-oxalate diet. As your body rids itself of excess oxalates through the process of oxalate dumping, symptoms can worsen before they improve. 

High oxalate foods

After some more research, I discovered that my diet of matcha and chia seeds with almond milk, celery dipped in almond butter, and spinach salads with other veggies was extremely high in oxalates. 

Some of the most problematic foods are the following:

Nuts and seeds: Almonds, walnuts, cashews, peanuts and peanut butter, pecans, sesame seeds

Greens, veggies, and tubers: Spinach, swiss chard, beets, and beet greens, sweet potatoes, rhubarb, celery, carrots, tomatoes (especially tomato sauce and tomato paste), parsnips, okra, artichokes, snap peas

Legumes: Soybeans, beans

Whole grains and pseudo grains: Wheat bran and wheat germ, quinoa, grits, barley, tapioca flour

Fruits: Kiwi, figs, berries (in high doses), especially blackberries and raspberries, apricots, tangerines, citrus peels like lemon peel and lime peel, prunes

Spices: Black pepper, turmeric, parsley, cumin, cinnamon

High-oxalate “superfoods”

To make matters worse, many high-oxalate foods are being promoted to “superfood” status. Some of the most notorious are spinach and beet greens, but even dark chocolate and cocoa, tea (black tea and green tea), chia seeds, and some of the “healthy” spices like turmeric and black pepper are quite high.

People trying to eat a healthier diet may actually turn to a very high oxalate one that causes them even more damage. This topic is covered in detail in the book, Toxic Superfoods by Sally K. Norton. I highly recommend reading the book if you believe you are suffering from oxalate overload.

Ironically, the more processed grains like white bread and white rice are lower in oxalates than the “healthier” full-bran or brown rice. Those avoiding grains or gluten may turn to high-oxalate alternatives like almond flour or buckwheat flour.

Nut and seed “milks” like almond milk, especially homemade, are also extremely high. Soy milk is also extremely high. Sadly, by trying to avoid the inflammation from dairy, many think they are choosing a healthier alternative but they may actually be making their health worse.

Problematic supplements

Too much of a good thing can also be very problematic.

During the pandemic, I worsened my problem by supplementing with high doses of vitamin C. While vitamin C is an essential nutrient, it is also a precursor to oxalate formation. Taking high doses of vitamin C may exacerbate oxalate problems or even be enough to cause them. 

I was also taking collagen, another precursor. While I still believe that making and consuming homemade bone broth is a very healthy addition to your diet, taking an excessive amount of concentrated collagen or gelatin can lead to oxalate issues.

Can you reduce oxalates by cooking or soaking them?

While you can slightly reduce the oxalates in some foods by boiling them for a long period of time and tossing the cooking water, it can only help so much.

Even if you could reduce them in a high-oxalate food by as much as 50%, it would still continue to have too many oxalates for most people with issues. In some cases, it may even make those oxalates more bioavailable and easier to absorb. 

Soaking and sprouting haven’t been shown to be very effective for reducing them either. 

Who is most susceptible?

Another myth about oxalates is that only some people are sensitive to them. I’ve heard it said that those who don’t have kidney stones have nothing to worry about and can eat as many oxalates as they want. This modern ignoring of the oxalate problem, though, is just that: ignorance.

There are cases of people who have either died or ended up on kidney dialysis after an oxalate overload. While death, like the man who died after eating sorrel soup, isn’t common, many people have developed kidney issues after adding a green smoothie detox to their health regimen. Notably, Liam Hemsworth developed kidney stones after incorporating “healthy” spinach smoothies and almond milk into his diet. 

That said, some people are more likely to have visible issues than others. We probably each have an individual tolerance level based on how quickly our body is able to eliminate them.

Oxalate absorption?

Those of us with a long history of antibiotic use are more likely sensitive to oxalates. One of the theories is that antibiotics kill a type of bacteria that may help with the elimination of oxalates.

There could be other reasons: antibiotic use can lead to small openings in the digestive tract called “leaky gut”. This could lead to an increase in oxalate absorption.

Other digestive issues, like gallbladder problems, or traumas to the digestive tract, like bariatric surgeries, may also lead to increased problems.

Those with autoimmune conditions, autism spectrum disorders, chronic fatigue syndrome, fibromyalgia, and other chronic illnesses may also be more sensitive. Leaky gut is also more common in people with these conditions, so their oxalate absorption may be higher.

Lastly, those with certain genetic mutations like MTHFR may have difficulty eliminating oxalates as well.

So what’s the solution?

If you’ve been experiencing any of the symptoms I mentioned earlier, consider reducing or eliminating high-oxalate foods from your diet.

You don’t have to switch to a carnivore diet like the one I’m currently on. In fact, it’s probably best not to make a drastic switch from a high oxalate diet to a very low one all at once. Doing so could lead to more serious dumping symptoms. I ended up with hives, but you could even end up with kidney stones or other kidney problems.

The best approach is to slowly reduce your oxalate intake by swapping the highest oxalate foods in your diet for nutrient-rich low-oxalate foods.

Low-oxalate foods include animal foods like meats, pasture-raised eggs, and wild-caught fish, and low-oxalate vegetables like cucumbers and romaine lettuce.

Lower oxalate alternatives

For those looking to reduce their oxalate intake, there are plenty of low-oxalate alternatives. While most of these foods are lower in oxalates, consuming some in large doses can add up. 

Fruits: Apples, bananas, blueberries, cantaloupe, grapes, honeydew melon, oranges, papaya, pears, avocados, peaches, lemon juice and lemonade, orange juice, lime juice (avoid citrus peels), pineapples, cherries

Vegetables: Asparagus, broccoli, cauliflower, cucumber, lettuce (romaine), mushrooms, onions, turnips, rutabaga, cilantro, cabbage, endive, mustard greens, kale, escarole, Brussels sprouts, chives

Grains and starches: Basmati rice, fresh corn, coconut flour, cornstarch

Animal products: Beef, ham, chicken, liver, fish like sardines, dairy products like cow’s milk, cheese, yogurt, kefir, buttermilk

Nuts and seeds: (In small doses) lower oxalate options are sunflower seeds, pumpkin seeds, flaxseeds, macadamia nuts, and walnuts.

Supplementation

To help support the body during detox, consider supplementation with minerals that can help with oxalate elimination. Some examples are calcium citrate, magnesium citrate, and potassium citrate.

B vitamins, especially B6, are also helpful throughout the elimination process. As is sulfur, which can be found in MSM. For those who can’t tolerate MSM or magnesium supplements, adding MSM and/or Epsom salts to baths and foot soaks can be helpful.

Sally K. Norton provides more information about supplementation during oxalate detoxing in her very thorough, well-researched book, Toxic Superfoods. (Read my review of the book here.)

How long will oxalate detox take?

Don’t try to rush through!

Normally, the progressive accumulation and storage of oxalates occurs throughout many years. Similarly, its elimination is a process that takes time to reverse. It can take anywhere from several months to several years, depending on how bad the problem was, to begin with.

Removing high-oxalate foods from your diet is only one part of the equation. The other part is providing your body with the necessary nutrients to support oxalate elimination and detoxification. This means eating a nutrient-rich diet, supplementing with the right minerals, and providing your body with the rest it needs.