Do spinach and kale make up the crux of your diet? Or does your diet consist mostly of nuts, seeds, and beets? Even though these are great foods, you might not be getting all the nutrients that you think you are. Why? Something called oxalates.

What are oxalates?

Oxalates are organic acids produced by plants used to protect themselves from insects. Oxalates might also be a byproduct of fungi such as candida and aspergillus. Normal metabolic processes also contribute as sources well.

How do oxalates affect my health?

Not everyone has an issue with oxalates. But if our body can’t process oxalates effectively, they can crystallize and act like shards of glass, creating irritation wherever they go. Oxalates can form crystals in the heart, bone, brain, and kidney, and when we excrete them from the kidneys, they can damage our genitalia, leading to vulvar pain in women.

When not bound to calcium, oxalate impairs mitochondrial functon, disrupts minerals, and creates oxidative stress.

What conditions are associated with high oxalate load?

• Fibromyalgia
• Kidney stones
• Anxiety
• leaky gut
• Autism
• Cataracts
• Breast cancer
• Endometriosis
• Fibroids
• PCOS 
• Interstitial cystitis
• Vulvodynia
• osteopenia/ osteoporosis
• Ear crystals/vertigo
• Diverticulosis/diverticulitis, 

Even thyroid issues may have an oxalate basis. Dr. Izabella Wentz, RhP and author of Hashimoto’s Thyroiditis: Lifestyle Interventions for Finding and Treating the Root Cause, states that autopsies have found that 79% of adults have oxalate crystals in their thyroid glands, which could lead to inflammation and autoimmune issues.

According to Andrew Rostenberg, DC, as oxalates are absorbed, they may force us to lose precious sulfates required for detoxification, growth and repair of our cells, moving blood, and detoxifying. Low sulfate can cause oxalate to get into cell and affect mitochondria function.

In addition to tissue damage, oxalates have been shown to inhibit our ability to metabolize carbs,  damage DNA, and cause oxidative stress.

But I believe a serious issue with oxalates is that they bind with minerals, thereby keeping us from absorbing things like zinc and calcium while simultaneously preventing the excretion of toxic metals like mercury and lead.

What is my oxalate load?

Oxalates are not like most food chemical issues or allergies where avoiding or limiting that food or chemical prevents symptoms. Oxalates get stored by the body similar to the way heavy metals are stored.

While they are coming in rapidly the body is in storage mode, but there is a limit to how much you can store before your body is overwhelmed and some of it starts “spilling over.”

Some people have no symptoms of oxalate overload, not because they aren’t absorbing excess oxalate, but just because they just haven’t hit their personal tipping point yet. They may be storing lots of oxalate in their bodies but in such a way that it isn’t causing obvious symptoms.

High doses of vitamin C as ascorbic acid can turn into oxalates in the body, despite not containing any oxalate themselves.

Normally, oxalates are bound together in the gut they are excreted in the stool before absorbing so those with GI issues may have higher circulating oxalates.

What are the symptoms of oxalate overload?

• Pain in the body
• Burning with urination (interstitial cystitis)
• Burning with bowel movements
• Leaky gut
• Depression
• Kidney stones
• Fatigue
• Vertigo
• Cloudy urine/crystals in urine
• Anxiety/depression
• Headache
• Thyroid issues
• More…

What is the root cause of oxalate overload?

Not everyone is sensitive to oxalates. The Oxalosis and Hyperoxaluria Foundation defines the different effects of oxalates:

• Dietary hyperoxaluria happens when you eat too many oxalate foods that can’t be eliminated by the body.
• Enteric hyperoxaluria conditions include intestinal disorders such SIBO, Crohn’s disease, short bowel syndrome, dysbiosis, systemic yeast, etc., all of which affect the ability to absorb nutrients and lead to oxalate storing.
• Primary hyperoxaluria :“A rare, genetic disorder of liver metabolism that often results in life-threatening damage to the kidneys. In this type, the liver doesn’t create enough of a certain protein (enzyme) that prevents overproduction of oxalate, or the enzyme doesn’t work properly. Unlike dietary or enteric hyperoxaluria, the amount of oxalate in the urine is not greatly affected by changes in dietary oxalate.”

In addition, having low levels of calcium could increase oxalate levels—we need calcium to bind to oxalates in order to remove them from the body.

Fat absorption issues can also affect oxalates from being effectively removed since oxalates should be bound in stool.

Additionally, we require a bacteria, oxalobacter formigenes, to breakdown oxalates. This prevents the molecules from being absorbed by body

Finally, genetic susceptibility coupled with risk factors such as leaky gut, yeast, etc. can contribute to oxalate overload or degradation issues. 

What foods contain oxalates?

Foods considered high in oxalates are those that contain more than 10 mg per serving. The University of Pittsburg Medical School has a good list of oxalate-rich foods on their website, plus they classify foods by their oxalate content. Find more here:

According to this study, it may be difficult to assess the true oxalate content in food.

” The variability in the oxalate content of foods will influence the accurate assessment of the amount of oxalate ingested in diets. To date, we have observed a large variability in many fresh foods and even in some processed foods. Factors known to influence the oxalate content of plants include the plant variety, the developmental stage of the plant, the season, and growth conditions”.

Additionally, “Variability caused by food processing, food preparation, and factors that influence the bioavailability of the food oxalate after its ingestion is another consideration.”

How much oxalate is safe to eat?

Nutrient-rich foods such as greens, nuts, and fruits contain oxalates. For those sensitive, since they are such healthy foods, we do not want to eliminate them from our diet—instead, it’s best to limit their intake while also supporting our body’s ability to remove them.

A normal diet includes about 250 mg of oxalates per day. For those who are sensitive to oxalates, we may choose to limit their intake to 40 to 60 mg daily, but that really varies per the individual. Again, we are NOT eliminating oxalates—we are reducing our intake of them.

I like to make this easier to implement but suggesting consuming only eat one high oxalate food per meal, if necessary, combined with low oxalate foods. This may help balance out the load. You can then slowly start to eliminate the higher oxalate foods over time. Additionally, this site provides four alternative  methods to help lower oxalate load. 

Keep in mind, common high oxalate containing foods include spinach, almonds, rhubarb, chard, celery juke, beets, miso, etc.

What is an oxalate dump?

If you completely stop eating oxalates or remove them too quickly from your diet, you may experience “oxalate dumping” as your body tries to get rid of them all at once. This may result in the same symptoms you experience if you have low calcium or magnesium levels, such as muscle aches, cramps, headaches, detox issues, etc.

To minimize this response, you should slowly start to reduce your intake of oxalates to about 100 mg per day. After your body adjusts to your new level, you can try to reduce your intake even further if needed.

Symptoms of a oxalate dump

• Joint pain
• Painful urination
• Excessive urination/bed wetting
• Burning with bowel movements
• Sandy” stools and cloudy urine
• White or black flecks in bowel movement
• Skin rashes
• Brain fog
• Eye pain
• Insomnia
• Anxiety/depression

How do I safety reduce oxalates?

It is important  to reduce oxalates very slowly, over time. It may take several weeks to months before you actually get to a “low oxalate” diet. It’s vital that you do not remove oxalates all at once – instead, reduce oxalates 5-10% per week. Oxalates levels are based on the amount per serving – serving size and cooking/preparation method are important.

What else can we do to minimize the effects of oxalates?

Diet

Those with compromised gut health, frequent antibiotic use, inflammation from any source, arthritis, fibromyalgia, or poor fatty acid digestion—may want to exclude oxalates from the diet or at the very least, support consumption.

Again, if you have a suspected issue, when a higher-oxalate food is consumed, it should be put on a rotated schedule of eating to prevent an over concentration of oxalates and minimization of oxalate related issues. 

It is also key is to drink lots of water and replace the loss of minerals and B vitamins that oxalates can cause.

Excess protein can lead to high levels of uric acid, so don’t overdo protein consumption, either—too much protein may cause stones to form. Another downside of excess animal protein consumption is that it lowers the levels of citrate in the blood, and citrate is necessary to block stone formation.

Gut Issues

We need to make sure that the gut is not “leaky” and that we can effectively process fats. If we can’t, fatty acids can join with calcium and oxalates destined to leave the body, thus not allowing them to be eliminated. Bile salts (ox bile) may help as well as phosphatidylcholine, taurine, and a good digestive enzyme.

Chronic gut conditions such as Crohn’s or ulcerative colitis may contribute to malabsorption and increased oxalate absorption.

Please address all yeast issues as they can contribute to high oxalate load.

Supplements

Calcium and magnesium

Calcium can block the absorption of oxalates, so folks with a low dietary intake of calcium are more likely to be oxalate-sensitive. You may also consider reducing your sodium intake to 2 to 3 mg per day. Why? When we consume too much sodium, the kidneys begin to excrete excess calcium from the urine.

If you choose to eat high amounts of oxalates in a meal, consider taking calcium citrate or magnesium citrate with the meal to help excrete them. It mist be the citrate form as they also help with oxalate overload. These minerals must be taken 30-60 minutes prior to eating to bind oxalates from food.

Vitamin B6

B6 deficiency has been associated with oxalate issues. Why B6? B6 is a required cofactor for the enzymes that break down oxalates. The Linus Pauling Nutrition Institute reported that “A group of more than 85,000 women without a prior history of kidney stones were followed over 14 years, and those who consumed 40 mg or more of vitamin B6 daily had only two-thirds the risk of developing kidney stones compared with those who consumed 3 mg or less.”

Care should be taken with supplementation, however, since daily amounts over 100 mg have been shown to possibly lead to pain and burning in the extremities. 

Please note: Some folks may have low protein intake or issues with breaking down proteins, which may in turn lead to having low lysine levels. This has a negative impact on B6 levels since lysine is required to move B6 around the body. 

How does Vitamin C affect oxalates?

High intake of vitamin C and iron can increase oxalate conversion, so we need to limit vitamin C supplementation, especially ascorbic acid.

A study posted in the Reviews of Urology shows that “…these articles clearly demonstrate that 1 to 2 grams of ascorbic acid administered daily to both normal subjects and calcium oxalate stone-formers result in no urinary pH changes but in increased oxalate excretion.”

Others such as Sterling Hill  believe that vitamin C should be from natural sources to minimize oxalate absorption and even then, should be limited to 400 mg per day.

Basically, the jury is still out on how much is the right amount of Vitamin C for those with oxalate issues.

How can you test for oxalates?

There are blood tests you can run through Labcorp, but the most common test is the Great Plains organic acids test (OAT) where they test directly for oxalic, glyceric, and glycolic acids. In addition, the test includes testing for byproducts of yeast (since yeast overgrowth goes hand-in-hand with high oxalate issues) as well as your B6 and citrate status.