The Dark Side of Spinach: What You Need to Know About Oxalates

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Eating a spinach salad or a handful of raw almonds sounds perfectly healthy. But for some people, compounds in these foods called oxalates can become a problem.

Oxalates are organic salts naturally present in many plant foods. Because they can bind calcium, zinc, and magnesium, preventing these critical minerals from being absorbed, oxalates are considered anti-nutrients. ¹

“Antinutrients are compounds found in foods that interfere with the absorption of beneficial nutrients and minerals,” says Dave Asprey. “They prevent the body from being the efficient micronutrient sponge that it was meant to be.” ²

About half of oxalate intake comes from plant foods. The other half, your body produces as waste products.³ They result when the body metabolizes vitamin C and a few other compounds. Excessive intake of protein and salt as well as a high-sugar impact diet can also increase your body’s oxalate production.

That’s where problems occur. Too many oxalates can form crystals in the urine. As a result, oxalate “sticks” or binds to calcium as your kidneys make urine. Over time, a high-oxalate diet (along with drinking too little water) can lead to calcium oxalate stones, the most common type of kidney stone.⁴

Plant Foods and Oxalates

Oxalates are naturally occurring in many vegetables, fruits, nuts, and other plant foods. However, these compounds are much higher in some foods than in others.

Despite its many health benefits, spinach is one of the highest-oxalate foods. One half-cup of cooked spinach can contain a whopping 755 mg, whereas a cup of raw spinach contains 656 mg of oxalates.

Other high-oxalate foods include:

• Potatoes (a medium baked potato has 97 mg)
• Rhubarb (541 mg in ½ cup)
• Raspberries (48 mg in 1 cup)
• Almonds (122 mg in 22 nuts)
• Cashews (49 mg in 1 oz)⁵

The good news is that some of the highest-oxalate foods — including soy, wheat, and peanuts — you’ll naturally eliminate on The Virgin Diet.

Conversely, many Virgin Diet-approved foods (things like asparagus, Brussels sprouts, broccoli, and freshly ground flaxseed) are low in oxalates.⁶

For others, you can make simple swaps to trade high-oxalate foods for lower-oxalate ones, including:

• Swap spinach for other leafy greens including Swiss chard and kale.
• Swap blueberries for strawberries.
• Swap grapes for fresh coconut.

How Do I Know if Oxalates Are a Problem?

If you’re healthy and you have a healthy gut (more on that in a minute), your body should be able to handle a moderate oxalate load.

That’s because in a healthy person, oxalate-containing foods travel through the digestive tract. As they make their way through your gut, they bind with calcium, and you excrete them. For these folks, oxalate buildup shouldn’t be a problem, and the benefits of nutrient-dense plant foods far outweigh their risks.

However, if you have oxalate sensitivities or you consume lots of high-oxalate foods, problems can occur. When you consume too many oxalates, they continue through to your kidneys. Over time, this may lead to kidney stones.⁷

Other signs that you may be sensitive to oxalates include:

• Inflammation
• Muscle and joint pain
• Burning sensations
• Irritation in the eyes, skin, other tissues, and mucous membranes⁸

You may also experience digestive symptoms like acid reflux, heartburn, bloating, constipation, diarrhea, and gas.

Oxalates are also a problem for people with hyperoxaluria, a metabolic disorder that often causes calcium oxalate kidney stones. Hyperoxaluria, or too much oxalate in your urine, occurs in two forms:

• Primary hyperoxaluria is inherited, due to defective enzyme activity.
• Secondary hyperoxaluria occurs from consuming high amounts of oxalates and oxalate precursors. It can also occur in people with an unhealthy gut.⁹

The following demographics have a greater risk of hyperoxaluria and should be particularly mindful of oxalate intake:

• Children who are diagnosed with kidney stones.
• Adults who have recurring kidney stones.
• People (regardless of age) who have a family history of kidney stones.
• People (regardless of age) with calcium deposits found in the kidney.
• People with renal failure of unknown cause.
• If your siblings have been diagnosed with primary hyperoxaluria.

If you meet any of these criteria, talk with your healthcare practitioner. Untreated hyperoxaluria can eventually lead to kidney damage, kidney failure, and death.¹⁰

Some people with primary or secondary hyperoxaluria may experience a rare type of arthritis called oxalate arthritis, when calcium oxalate crystals deposit within bones, tendons, cartilage, and synovium (the connective tissue that lines the inside of your joints). From these sites, the crystals may enter synovial fluid, where they create an inflammatory response.¹¹

Those oxalate disorders eventually impact the heart, skin, teeth, and other parts of the body.¹² This process, called systemic oxalosis, occurs when your intake of calcium oxalate burden exceeds your body’s ability to excrete calcium oxalate.¹³

“When oxalates bind to calcium in your blood, tiny, sharp oxalic acid crystals form and can be deposited anywhere in the body and cause muscle pain,” says Asprey. “Oxalates also cause a condition in women called vulvodynia, which leads to painful sex because of oxalic acid crystals in the labia.”¹⁴

If you suspect that you’re sensitive to oxalates or you’re prone to kidney stones or have kidney disease, your doctor may encourage you to follow a low-oxalate diet. Typically, that means less than 50 mg of total oxalate intake daily.¹⁵

For people other than those with hyperoxaluria or oxalate sensitivities, a moderate intake of oxalates shouldn’t be a problem. However, some experts believe a low-oxalate diet may benefit certain conditions, including autism spectrum disorders (ASD), chronic candida, chronic fatigue, fibromyalgia, and thyroid disease.¹⁶

5 Ways to Manage Oxalate Intake

Regardless of whether you have hyperoxaluria or oxalate sensitivities, monitoring your oxalate intake is a smart idea.

Since there’s no lab test for oxalate sensitivity yet, a low-oxalate diet–reducing or eliminating high-oxalate foods–is your best bet if you suspect any of the signs and symptoms listed above might be oxalate-related. Here are five more ways to manage oxalate intake.

Manage Your Oxalate Intake #1: Prepare Your Food Smartly

Preparing food properly can reduce your intake of oxalates. Boiling vegetables can reduce oxalates by 30–90%. One review found that boiling spinach and Swiss chard reduced their oxalate load by 87% and 85%, respectively.

While steaming has a lesser impact, it can also reduce oxalate load. That same review found steaming green Swiss chard and spinach reduced oxalate load by 46% and 42%, respectively.¹⁷

Soaking is another option. One study found that soaking raw taro leaves, which are high in oxalates and potentially poisonous when consumed raw, in water for 30 minutes can reduce oxalates. Soaking for 18 hours, on the other hand, reduced oxalates by an impressive 26%. Boiling the taro leaves, on the other hand, reduced oxalates 36%.¹⁸

Manage Your Oxalate Intake #2: Get Sufficient Calcium

An alternative approach to counting oxalate intake is to eat more calcium-rich foods when you eat foods high in oxalate. That’s because oxalates and calcium can bind together before they get to the kidneys, reducing your risk of kidney stones.¹⁹

Especially for people at risk for kidney stones, reducing intake of high-oxalate-containing foods and getting sufficient amounts of calcium may help reduce that risk.²⁰

Vegetarians who eat large amounts of vegetables may also get a high amount of oxalates, which may reduce calcium availability. This may especially be an issue for women, who require greater amounts of calcium.²¹

Swallowing calcium supplements and drinking low-fat milk is not the way to get more of this critical mineral. Leafy greens, nuts, and seeds are great sources of calcium. Just go for lower-oxalate foods if you suspect oxalate sensitivity. And look for a high-quality calcium supplement that also contains other nutrients including magnesium. (Stay tuned! We’re developing a unique bone-support formula and will let you know when it’s available.)

Listen here to learn more about the best ways to get calcium.

Manage Your Oxalate Intake #3: Drink Up

When your kidneys try to excrete waste with too little liquid, crystals can begin to form, which can lead to stones. Staying hydrated can help prevent this from occurring. Here are three ways to do that:

1. Drink sufficient amounts of clean, filtered water throughout the day. Keep a BPA-free canteen nearby and sip liberally. How much water do you need daily? Find out here.
2. Drink organic green tea. While green tea contains moderate amounts of oxalates, its high antioxidant content may help prevent kidney stone formation.²²
3. Try lemon juice. Research shows that citrates may help increase the excretion of oxalates.²³ Adding a little lemon juice to a glass of water is a great way to start your day. And my Lemon-Aid recipe combines lemon with other ingredients like crave-crushing L-glutamine powder for a satisfying, hunger-quenching beverage.

Manage Your Oxalate Intake #4: Get the Right Nutrients

A high-quality multivitamin-mineral along with omega-3 fatty acids can support your body’s ability to manage oxalates.

Vitamin B6, to use one example, helps break down oxalate and potentially lower the body’s production of oxalates. Omega-3 fatty acids can also help manage your oxalate load.*²⁴

Our Daily Essentials Packets combine a superior multivitamin and omega-3 fatty acids… in one convenient, easy-to-take packet. You can only get them here. *

Manage Your Oxalate Intake #5: Heal Your Gut

This last one is so important but often neglected.

One of the biggest culprits for oxalate sensitivities, where your body becomes intolerant of oxalates, is poor gut health.

In a healthy gut, bacteria can help break down some oxalates before they bind to minerals. In fact, some bacteria can use oxalates for energy, reducing the number of oxalates your body absorbs.

One study found that having healthy amounts of the bacterium Oxalobacter formigenes may reduce the risk for recurring calcium oxalate stone formation by 70%.²⁶

But if you have imbalances in these trillions of bacteria, oxalates may build up or otherwise become a problem. With leaky gut, to use one example, an excess of oxalates can seep into the body instead of being filtered out. I talk extensively about leaky gut in The Virgin Diet, including ways to heal your gut.

Learn more about leaky gut and how it can sabotage your health in this blog.

Final Thoughts

Should you be concerned about eating high-oxalate foods like spinach?

If you have a healthy gut, don’t have hyperoxaluria, and don’t suspect any signs and symptoms of oxalate sensitivities, you can probably handle moderate amounts of these foods.

I recommend steaming or otherwise cooking these plant foods, and avoid eating too many high-oxalate plant foods (such as raw spinach).

If you’re considering a low-oxalate diet, keeping a list of low- and high-oxalate foods nearby can help. I highly recommend working with a functional medicine nutritionist or doctor if you do this. Lowering your intake of oxalates too quickly can lead to oxalate dumping, which can lead to symptoms including fatigue, dizziness, pain, and irritability.

For most people, these symptoms last a few days or weeks as the body excretes stored oxalates. To prevent oxalate dumping, ​​lower your oxalate intake by 5–10% per week.²⁷

Before you go…

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The views in this blog by JJ Virgin should never be used as a substitute for professional medical advice. Please work with a healthcare practitioner concerning any medical problem or concern. The information here is not intended to diagnose, treat, or prevent any disease or condition. Statements contained here have not been evaluated by the Food and Drug Administration.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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