Insoluble calcium oxalate is what can really cause problems for the human body, because it forms a sharp crystal like structure.
Oxalates are ubiquitous in plant foods. They occur in over 200 plant families and in some plants comprise over 80% of the dry weight [*].
The plants it’s most prevalent in are: leafy greens, fruits, nuts, seeds and cocoa [*]. Ironically, these are the foods that people tend to think are the most healthy…thanks a lot popeye.
When you eat spinach, do you know that weird texture on your tongue and the roof of your mouth? Well hopefully you don’t remember because you don’t eat spinach.
But this is the oxalate content and is a defense mechanism for plants.
People that think they’re being healthy by overpaying for a green smoothies are actually flooding themselves with damaging oxalates.
Oxalates Are a Defense Mechanisms for Plants
What is the function of oxalates in plants? They’re used as protection from infection and being eaten.
Animals use the oxalates in two main ways.
The first is that they are very abrasive and damaging. Insoluble oxalates form crystals that can actually tear up the teeth of the bugs that are eating them.
Animals have shown a distinct preference for eating foods deprived of these oxalates.
Larvae that eat food rich in oxalates show noticeable wear and tear. [*]
These crystals are like razor blades and are physically damaging to tissues. Below is a photo of the oxalate crystal like structure.
Oxalates can also be toxic to predators. In an experiment, one group of larvae were fed a diet high in oxalates. The researchers found that they larvae with high oxalate consumption didn’t grow as large [*].
Researchers also found higher mortality rates at larger stages of larva growth.
Part of the way oxalates lead to higher mortality rates is because they bind to nutrients and reduce their bioavailability. They’re actually a sneaky way to make the diets the predators are eating much less nutritious.
Many insects recognize this and avoid foods high in oxalates. In one study, researchers applied calcium oxalate to the outside of funghi and flies stopped feeding on the mushrooms.
Additionally, a study of 46 conifers showed that there was a negative correlation between the amount of calcium oxalate and how much they were eaten by bark beetles [*]
High Oxalate Foods…This is a Big Problem with Keto
Oxalates are found in over 200 plant species, but some contain more than others.
Over the last few decades, oxalates in our diet have increased substantially. This is largely because of the de-emphasis on animal foods and the allure of the “real food”, vegetarian movement.
However, none of the evangelists of these diets have considered the bioavailability of nutrients or the toxic substances they contain.
Paradoxically, the obsession with superfoods has hurt some people’s health. Some of these noble superfoods are the highest in oxalates and antinutrients: spinach, beets, blackberries, sweet potatoes, turmeric, cinnamon and chocolate.
The average daily intake of oxalate is around 150mg. One green smoothie alone can have 500-800mg.
Below are some other foods that have over 100mg per serving.
The 12 highest oxalate foods (100–900 mg per serving) include:
Keto dieters need to be especially aware because many of these vegetables that are recommended to be eaten liberally are very high in oxalates.
Throughout evolutionary history, these foods were never available year round due to seasonality. But now they are ubiquitous.
Walk around any metropolitan city and you’re sure to find someone carrying an overpriced spinach and kale smoothie, mixed with non dairy almond milk, and touting the health benefits (probably instagramming about how they’re saving the environment).
But these green smoothies flood your body with these oxalate crystals.
How Do Oxalates Cause Damage to Humans?
Oxalates are one of the most effective plant weapons. Insect predators are aware of the consequences.
But humans have taken the bait and fallen for the marketing. The damage to humans is much more insidious and occurs over the long term, so the immediate consequences aren’t always apparent.
It’s almost like the insects are smarter than we are.
How do they cause damage?
Oxalates are toxins. Plain and simple. You can’t use them in any way, so whenever you ingest them your body tries to get rid of them. The process is slightly different depending on whether the oxalates are soluble or insoluble.
Soluble and free oxalic acid is absorbed through the intestines and excreted into the urine.
Insoluble oxalates are not absorbed. Instead, they have an affinity for calcium and try to bind to it (the two are like Romeo and Juliet together). It’s quite romantic.
Because you can’t absorb insoluble oxalates, you excrete them through the feces.
Dietary calcium can actually protect you against the damage of the oxalates by binding to it. But on the other hand, it reduces the bioavailability of calcium in your diet (because the calcium is excreted instead of used).
In a normal scenario, your body should do a good job expelling oxalates. However, if you have gut issues or leaky gut, you’ll have a much harder time expelling them.
There are two main ways oxalates cause damage. Mechanically and biochemically.
Because oxalates are so abrasive, even the process of expelling them can cause damage.
Oxalate crystals are very abrasive and cause a tremendous amount of wear and tear.
When you have high circulating levels in your blood, they can be deposited in almost any organ in your body: thyroid, kidney, lymph nodes, intestines, eyes and skin [*] [*].
These crystals are not something you want deposited in your organs. It’s basically like filling your body with tiny razor blades that can mechanically shred tissues.
Similar to an oyster, if you open us up and you’ll often find some pearly crystals inside. Except in this case, the crystals are destroying your health
Oxalates also work on a biochemical level. Smaller oxalate crystals called nano crystals can pass through your cell membranes.
When they get into the cell they inhibit enzymes that convert fuel into energy (such as biotin enzymes) These enzymes are critical for maintaining an energy balance and metabolic flexibility.
When it gets into the cell, it can poison and disrupt many processes [*]
High oxalate levels can cause cells to swell up and burst
Depletes antioxidants like glutathione
Destruction of organelles
Rupture of lysosomes leading to the release of destructive enzymes
When to Be Worried About Oxalates?
People with impeccable health and immune systems don’t need to be as concerned about oxalate content. But spoiler alert, that’s not me. And if you’re reading this, it’s probably not you either.
If you have any of the issues below, you need to be very careful with oxalate intake. The gut issues are especially important because instead of excreting oxalates, issues like leaky gut can allow them to sneak into your bloodstream where they’ll wreak even more havoc.
Leaky gut syndrome
Irritable bowel syndrome (IBS)
Inflammatory bowel disease (IBD)
Small intestinal bacterial overgrowth (SIBO)
Autoimmune diseases such as chronic fatigue syndrome
Chronic inflammation related diseases
Dangers of High Oxalate Food Consumption
Too much oxalate in the urine and bloodstream is called enteric hyperoxaluria. This is caused by fat malabsorption, gut dysfunction and / or a high oxalate diet [*]
Basically, various factors are causing you to absorb way too much oxalate and your circulating oxalate is through the roof.
Over time, high oxalate levels will damage tissue and organs throughout your body.
The symptoms of oxalate toxicity are often hard to identify because they are subtle and damage occurs over the long term. It’s not like 1 spinach smoothie will cause your face to blow up like a balloon.
But over time, the damage can be severe. Given the ubiquitous prevalence of leaky gut and the excessive consumption of high oxalate foods, I believe that many people are suffering from issues stemming from high oxalate consumption.
Below are some of the main consequences.
1. Kidney Stones
The majority of research of oxalate impact is on the kidney.
When oxalate is high in the blood it goes to the kidney. Soluble oxalates are mainly excreted through urine so the kidney plays a big role.
In the kidney, oxalates can bind with calcium and wedge themselves into its tissue [*]. Because of this mechanism, roughly 80% of kidney stones are calcium oxalate.
And no wonder kidney stones are on the rise in the US [*]. People can’t get enough of their leafy green superfoods (i.e. poison).
Reducing oxalate content is an effective treatment for kidney stones.
2. Renal Failure
Over time, oxalates can damage the kidney enough to cause renal failure. The kidney is the main organ focused on excretion, and the stress and inflammation from oxalates can overwhelm it. [*]
3. Reduced Calcium, Magnesium and Zinc Absorption
Oxalates are like magnets for minerals. The most common mineral that it attracts is calcium. Because oxalates are expelled from the body as fast as possible, the calcium is attracts is no longer absorbed.
So if you’re eating calcium and high oxalate foods together, you’ll only actually be getting a fraction of that calcium.
This is why plant foods are often inferior sources of nutrients to animal products.
Many people think that spinach is a good source of calcium. But they’re almost as wrong as the people who think carbohydrates are good for you.
The calcium in spinach is completely useless. It’s all tied up in oxalate and you excrete it all. And this is true for all high-oxalate foods.
According to Dr. Weil:
“For example, although the calcium in spinach is 115 mg per half cup cooked, because of the interference of oxalic acid, you would have to eat more than 16 cups of raw or more than eight cups of cooked spinach to get the amount of calcium available in one cup of yogurt.” — Dr Weil
Additionally, a study tested consuming a high fiber diet with spinach, which is high in oxalates, vs the same diet with lower oxalate cauliflower.
Calcium, magnesium and zinc absorption were all lower on the diet higher in oxalates [*].
4. Mitochondrial Dysfunction
Maintaining mitochondrial function is a critical aspect to maintaining health.
Mitochondrial dysfunction is associated with many chronic diseases, including cancer [*]. Despite being touted as longevity promoting superfoods, high oxalate foods can severely damage the mitochondria.
Mitochondria produce reactive oxygen species. They are atoms with an unpaired electron, which repel throughout your body looking for a match. Think of this like a drunk person at a single’s bar…
If they go unchecked, they can damage DNA, proteins and healthy mitochondria.
Your body produces antioxidants to neutralize these reactive oxygen species: glutathione and superoxide dismutase. They’re both critical to maintaining mitochondrial health.
However, oxalates deplete both of these antioxidants and can damage mitochondrial function [*].
Patients with kidney stones have been shown to have decreased mitochondrial function in their white blood cells [*]
The increased mitochondrial damage and dysfunction produces even more free radicals that lead to DNA damage and cancer [*]
“Results of clinical and experimental studies show that renal epithelial exposure to high oxalate and crystals of CaOx/calcium phosphate (CaP) generates excess ROS, causing injury and inflammation” [*]
Which is ironic because many of these superfoods people eat are because they’re supposedly “antioxidants”. They’re really causing these “reactive oxygen species” and free radicals [*].
5. Arthritis and Joint Pain
Joint pain is one of the most common symptoms of high oxalate consumption. Many people are unaware of how much oxalates contribute to these problems.
Oxalate crystals can actually lodge themselves into joints. If you remember the structure, they are very abrasive and can cause pain every time you move the joint [*] [*].
When oxalates are deposited into your organ tissues, they trigger inflammation. Specifically the NLPR-3 inflammasome [*].
NLPR-3 has been implicated in numerous chronic diseases, including cancer [*].
This study found that patients with Autism had 3x the levels of oxalates in their blood than normal individuals. [*]
Researcher Susan Owens has also shown drastic improvement in autism symptoms when removing oxalates from the diet [*]
The exact metabolic pathways are unclear, but a few mechanisms have been hypothesized.
Gastroinstestinal problems are common in children with autism and intestinal permeability likely plays a role[*].
Researchers in this study also proposed that increased permeability may allow oxalates to disrupt the blood-brain barrier and interfere with central nervous system function.
8. Leaky Gut and Gut Dysbiosis
Oxalates are an even bigger concern if you already have leaky gut.
But they can also cause leaky gut and gut dysbiosis. Gut bacteria is necessary to degrade oxalates in the gut, but over time Oxalates can actually kill those bacteria [*].
One big problem with oxalates is that we cannot digest them. They pass directly to the GI tract and because of their crystal-like structure, they can irritate the gut.
If you give these bacteria too many by force feeding them almond milk or green smoothies on a daily basis, they’ll give up and die.
There’s a war going on in your gut between oxalates and bacteria, and the oxalates are winning.
Gut dysbiosis can lead to leaky gut, which then makes the problem even worse.
9. Skin and Eye Issues
High circulating oxalate levels leads to deposits in numerous organs throughout the body. Two of the most common are the skin and eyes [*].
Oxalates are abrasive causing skin and eye issues when deposited there.
Neuropathy is a disease where you have numbness in the hands and feet. Similar to the joints, oxalate crystals can make themselves at home in your peripheral nerves in the feet and hands.
In this study, a 61 year old man who had neuropathy, had crystal deposits in his nerve tissues [*].
11. Thyroid Issues and Hypothyroidism
One of the oxalates other favorite crawl into is the thyroid. There, oxalate binds to T3, a hormone that the thyroid releases.
This study showed oxalates in 79 out of 100 thyroid glands in routine autopsies [*].
T3 and thryoid hormones help to regulate many functions including:
Central and peripheral nervous systems
This can disturb your natural thyroid hormonal balance.
Another study found that rats fed a diet with 5% oxalic acid developed hypothyroidism and had severe body weight losses [*]
12. Cystic Fibrosis
A study of 26 children with cystic fibrosis and no symptoms of kidney stones, showed that 14 had elevated levels of oxalate excretion [*]
This is just associative, but if you have cystic fibrosis you should be aware of this potential cause.
Symptoms of Issues with Oxalates
Fix Oxalate Issues with the Carnivore Diet
The human body isn’t designed to have access to these high oxalate foods all year round. Hunter-gatherers never ate oxalates in such high concetrations and throughout the year like we do.
But people today are constantly barraging their bodies with oxalates and over time their bodies will give in.
The best way to fix these issues?
The carnivore diet is the best diet for oxalate based problems. And I think this is a big reason why we’re seeing some of the miraculous improvements in health that we are.S
How does the carnivore diet improve problems with oxalates?
The Carnivore Diet Can Heal the Gut
The carnivore diet cuts out anti-nutrients, fiber and inflammatory sludge. This improves the gut microbiome by starving bad bacteria and strengthening the good bacteria.
Lowering inflammation is the most important thing you can do for your gut health.
Low Thiamin (B1) levels will increase your body’s endogenous oxalate production.
Thiamin is an important coenzyme for carbohydrate metabolism. Excessive consumption of carbohydrates can lead to Vitamin b1 deficiency [*].
So people that are both eating a higher carbohydrate diet and a diet high in oxalates, are flooding their body with these toxic crystals.
And to make matters worse, spinach and vegetables don’t have the Thiamin necessary to replenish their levels. 100g of Spinach has only 10% of the daily RDA.
Thiamine deprived rats have much higher levels of oxalate production [*].
500g of steak and 100g of beef liver will get you >60% of your daily Vitamin B1 needs.
Meat is Rich in B6
Low B6 increases oxalate production. How? Your body can’t convert the oxalate precursor glyoxalate to the amino acid glycine without sufficient b6. Instead your body synthesizes oxalate instead because you have no b6.
This study shows that b6 deficient mice can develop excessive oxalate levels [*]
Animal products have substantial amounts of b6 and they’re in the most bioavailable form.
Just 100g of beef liver has 60% of your daily needs. And spinach, which is already raising your oxalate level, only has about 15% of your daily RDA.
Steak and liver are like mr. clean for oxalates.
The Carnivore Diet is a Low Oxalate Diet
If you eat what humans are made to eat — red meat — you can cut out the overhyped antioxidant superfoods, and power yourself off the most nutritious food in the world.
Red meat has all of the nutrients that humans need, in the perfect quantities. And it has no oxalate content.
And the ketogenic diet increases our endogenous antioxidant levels [*]. Juice cleanses are destroying your health. Eat red meat instead.
Recent obsession with plant superfoods has dramatically increased the amount of antinutrients in diets.
A naive obsession with “noble” antioxidants has ironically flooded people’s diet with oxidative stressful and inflammatory toxins.
Oxalates in our diets have skyrocketed and so have many of the health issues it brings.
If you want to lower oxalate levels and make yourself immune to chronic disease, you need to start the carnivore diet.
Someone told me that black pepper can be poisonous if you use a lot. True?
Maybe, but you would have to use an awful lot of pepper for a long time to run into trouble. The concern about pepper arises from one of its components, safrole, also found in small amounts in star anise, nutmeg, witch hazel, and basil. In the 1960s, the FDA banned the use of safrole in food in the United States after it was found that injecting large amounts caused liver cancer in lab rats. Perhaps the biggest effect of this ban has been to eliminate the use of sassafras root in the making of root beer. Volatile oils found in the bark of the root of the sassafras plant are 80 percent safrole. Nowadays, sassafras can be used as an ingredient in root beer only if the safrole is removed through a laboratory extraction process.
Black pepper is the most popular spice in the world, and black, green and white peppercorns all come from the black pepper plant (Piper nigrum), native to Asia. Black is the whole, partially ripened fruit; green is the unripe fruit; and white is the peeled seed.
I’m not that concerned about safrole. Eating moderate amount of it in plant products (such as sassafras tea) is not comparable to injecting large amounts of the pure chemical into the abdomens of rats. But black pepper can be an irritant of the GI tract, urinary tract, and prostate, and I don’t think it should be consumed frequently in quantity.
I generally don’t let waiters grind their pepper mills over my food at restaurants until I taste it first. For a hot spice, I prefer red pepper, which comes from a different plant (Capsicum spp.), doesn’t have any natural carcinogenic activity, has a long history of medicinal use, and provides healthful carotenoids. It can help lower cholesterol and stimulate circulation, and can actually help heal the lining of the stomach.
While we’re on the subject of pepper, you should know that pink peppercorns are not true pepper. They’re the dried berries of the Brazilian pepper tree (Schinus terebinthfolius) and have become popular despite questions about their safety. Pink peppercorns can cause symptoms resembling those of poison ivy/oak, as well as headaches, swollen eyelids, shortness of breath, chest pains, sore throat, hoarseness, upset stomach, diarrhea and hemorrhoids. I avoid them.
Finally, Sichuan peppercorns, used in East Asian cuisine, are the dried fruits of the prickly ash tree (Zanthoxylum piperitum). They have an interesting numbing effect on the tongue in addition to a peppery flavor, and their toxicity appears to be minimal.
Source: Article by Dr. Andrew Weil, M.D. (https://www.drweil.com/diet-nutrition/cooking-cookware/easy-on-the-black-pepper/)