Plant Oxalates

Plant oxalates and lectins are two distinct components found in certain plants, but they serve different purposes and have different effects on the body.

Plant Oxalates: Oxalates are compounds, primarily calcium oxalate, found in various plants. They are natural substances that plants use for various functions, such as calcium regulation, defense mechanisms against herbivores, and structural support. In terms of human health, high intake of foods rich in oxalates can increase the risk of kidney stone formation in susceptible individuals. Oxalates can combine with calcium in the urinary tract, forming crystals that can accumulate and lead to stone development. However, it's important to note that not all individuals are equally sensitive to oxalates, and a balanced diet usually poses no issue for most people.

Symptoms and causes of oxalate sensitivity.

The majority of people excrete oxalates through waste before they can pose an issue. However, those with oxalate sensitivities are thought to absorb more oxalate than they need or have trouble getting rid of excess oxalates. Oxalate sensitivity is not an official medical diagnosis, but I've personally seen it present in the following ways in my patients:

• Bloating

• Burning + tingling in your mouth and throat

• Constipation

• Diarrhea

• Gas

• Kidney stones

• Muscle weakness and Cramping

• Nausea

We still don't know exactly what causes oxalate sensitivity, but some researchers believe it has to do with either leaky gut syndrome3 or mold toxicity4 (or both).

MORE Functional medical doctors believe that leaky gut (also not currently a recognized medical diagnosis) occurs when your delicate intestinal lining is compromised. This causes undigested food particles and bacterial endotoxins to pass from the digestive system into your bloodstream and the rest of your body where it doesn't belong. This can put your immune system in overdrive and lead to increased inflammation throughout your body. With this hyper-awareness, your immune system may end up reacting to almost any food that passes through, including healthy, high-oxalate foods like spinach.

Mold toxicity and mold-related diseases aren't given the weight they deserve in conventional medicine, leaving many suffering for years without any answers. Since every person's biochemistry is different, mold toxicity can manifest in various symptoms, especially considering the type of mold strain you are exposed to. Studies have shown a connection between people who were exposed to high levels of Aspergillus niger—a mold species often found in water-damaged buildings—and oxalate sensitivity due to the fact that this species of mold produces oxalate crystals.

Foods that are high in oxalates.

These are some high-oxalate5 foods to watch out for if you have an increased risk of kidney stones or believe you are sensitive to oxalates:

• Beets

• Black pepper

• Carrots

• Chocolate

• Chard

• Dates

• Oranges

• Kale

• Kiwi

• Legumes

• Nuts (check here-some are ok)

• Potatoes

• Pumpkin seeds

• Radishes

• Rhubarb

• Spinach

• Sunflower seeds

• Tofu

• Turnips

Oxalates are present to some degree in most foods—particularly healthy plant foods. This means that you don't need to give up oxalates altogether (and doing so can hold you back from your health goals).

Instead, I recommend staying below ~50 mg of oxalates per day (though everyone is different) if you suspect you have a sensitivity. This way, you're still getting enough fiber and phytonutrients from plant foods that your body needs to thrive.

Foods that are lower in oxalates.

Foods are typically categorized into four different groups based on their oxalate content:

• Very high: <100 mg per serving

• High: 26–99 mg per serving

• Moderate: 10–25 mg per serving

• Low: 5–9 mg per serving

Foods in the moderate to low oxalate category:

• Bananas

• Apples

• Lemons

• Peaches

• Cabbage

• Mushrooms

• Zucchini

• Broccoli

• Cauliflower

• Eggs

• Meat

• Fish

• Poultry

• Cheese

• Milk

• Butter

• Coffee

High-Oxalate Nuts:

Almonds: 1 cup of almonds contains approximately 275-300 mg of oxalate

Cashews: 1 cup of cashews contains approximately 250-275 mg of oxalate

Pistachios: 1 cup of pistachios contains approximately 200-225 mg of oxalate

Peanuts: 1 cup of peanuts contains approximately 150-175 mg of oxalate

Low-Oxalate Nuts:

Macadamia nuts: 1 cup of macadamia nuts contains approximately 50-75 mg of oxalate

Hazelnuts: 1 cup of hazelnuts contains approximately 50-75 mg of oxalate

Pecans: 1 cup of pecans contains approximately 25-50 mg of oxalate

Walnuts: 1 cup of walnuts contains approximately 25-50 mg of oxalate

Other Considerations:

Roasting or cooking nuts can increase their oxalate content.

Some nuts, like peanuts, are often processed with high-oxalate ingredients, which can increase their overall oxalate

You can also mitigate the oxalate content of high-oxalate foods by adding a few extra steps before eating. For example, studies have found that cooked vegetables have a lower oxalate content than raw ones. Soaking and cooking nuts, seeds, and legumes before eating can also reduce their oxalate content.

The takeaway.

Even though oxalate sensitivity can come with a list of not-so-fun side effects, cutting out or cooking foods that are highest in oxalate may help with this uncomfortable issue. A functional medicine expert can run labs and complete a comprehensive health history to determine what is going on beneath the surface and walk alongside you during your healing journey.

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