Oxalate Problems, and What Foods Have High or Low Oxalates?

Understanding oxalates, how they affect us, and what foods contain them

Oxalic acid is recognized as a toxic and corrosive substance found in some plant foods. When bound to minerals, it forms compounds known as oxalates, like sodium oxalate or calcium oxalate. These oxalates are prone to crystallization, often contributing to the formation of kidney stones and other health problems.

Origin of Oxalic Acid

Plants produce oxalic acid, likely for seed germination, mineral management, or as a defense mechanism. When you consume plant-based foods, you ingest oxalates, which can be dissolved or crystallized, varying in size and shape. 

Your body also generates oxalate as a metabolic byproduct, with no identified beneficial function. The production of oxalate in the body can increase due to a deficiency in vitamin B6 or excessive intake of vitamin C. Certain fungi, particularly Aspergillus, are known for oxalate production in soil.

The Harmful Effects of Oxalates

The body can’t break down oxalates, making their excretion critical. Handling oxalates is risky for cells, as oxalates can bind to essential minerals from both your diet and body, rendering them useless. 

This "anti-nutrient" property can lead to mineral deficiencies affecting growth and reproduction. Oxalates can also bind with harmful metals like lead or mercury, adding to their toxicity. The corrosive nature of oxalates can damage the digestive lining and may lead to gastrointestinal diseases, intestinal permeability (leaky gut), and systemic inflammation. 

Furthermore, oxalates challenge the kidneys, potentially overwhelming their capacity to filter these compounds from the blood. They can form nano-sized and micron-sized crystals that accumulate in various body tissues, causing irritation and inflammation. These crystals might collect in different body parts, including arterial plaque, and are a common component of kidney stones.

Crystal Formation and Its Implications

Blood transports oxalates to various tissues, and factors like high concentrations of oxalates can encourage crystallization and deposits in the body. Insufficient citrate levels can also promote oxalate crystallization. Even when not forming crystals, oxalate deposits can disrupt cell biochemistry.

Individual Responses to Oxalates

The extent to which people are affected by dietary oxalates varies, and the issue often goes unrecognized. Symptoms might not directly correlate with recent oxalate intake and can flare up as the body releases stored oxalates. 

Blood and urine tests for oxalate levels are not always conclusive, as they do not necessarily reflect the extent of oxalate accumulation in the body.

Lifestyle and Dietary Influences

Modern lifestyles may increase susceptibility to oxalate-related issues. High-oxalate diets are more accessible than ever, and certain health-conscious choices like spinach and almonds could inadvertently increase oxalate intake. 

Medications can affect the body's ability to process and excrete oxalates, compounding their potential harm. Dietary patterns, such as meals rich in calcium and fiber, can impact oxalate absorption. Factors like gender, genetics, and age also influence how the body handles oxalates.

Identifying and Addressing Oxalate Issues

Determining if oxalates are causing health problems can be challenging, as most healthcare providers are unfamiliar with the concept. Accepted medical tests are invasive and typically reserved for severe cases. There is no uniform pattern of symptoms for oxalate toxicity, but kidney stones or multiple unexplained health issues could suggest a problem with oxalates.

Revero-Friendly Low-Oxalate Foods

The following list could be useful if you’re advised by Revero to avoid oxalates. The list includes foods that are both low-carbohydrate as well as low-oxalate. It is not all-inclusive, as other foods are low-carbohydrate and low-oxalate, so consider this a starting point. 

Low-oxalate, non-starchy vegetables:

• Arugula
• Bok choy
• Cabbage
• Cauliflower
• Celeriac root
• Chives
• Cucumber
• Lettuce (butter, iceberg, romaine, bibb)
• Mushrooms
• Radish
• Red bell pepper
• Watercress
• Zucchini

Low-oxalate beverages:

• Water (spring, filtered, or sparkling)
• Herbal tea (e.g., peppermint, chamomile)
• Black coffee
• Water
• Dry wine or hard liquor in small quantities

Meats: 

As oxalates occur in plant foods, meats, poultry, seafood, and eggs do not have high levels of oxalates.

• Beef
• Chicken
• Turkey
• Pork
• Lamb
• Fish (e.g., salmon, trout, cod)
• Shellfish (e.g., shrimp, lobster, crab)
• Eggs

Low-oxalate herbs and spices:

• Basil
• Cilantro
• Dill
• Fresh garlic
• Ginger
• Marjoram
• Parsley
• Rosemary
• Sage
• Tarragon
• Thyme
• White pepper

Low-Oxalate Nuts and Seeds:

• Flax seeds
• Sunflower seeds (hulled)
• Pumpkin seeds (pepitas)
• Macadamia nuts
• Pecans
• Pistachios
• Walnuts

High Oxalate Foods

If your Revero personalized diet suggests avoiding oxalates look below for many high-oxalate foods. Remember that oxalates come from plant-based foods. Refer to the Revero-Friendly Low-Oxalate Foods list above for information about those foods that contain acceptably low oxalate levels and are low-carb. 

This list does not include all high-oxalate foods. Contact your health coach for help identifying oxalates in foods, not on this list. 

Note: Some foods listed are not allowed on the Revero low-carbohydrate diet and are included for educational purposes only.

High-oxalate vegetables:

• Spinach
• Swiss chard
• Beet greens
• Rhubarb
• Okra
• Leeks
• Beets
• Parsnips
• Brussels Sprouts
• Eggplant

High-oxalate fruits:

• Blackberries
• Blueberries
• Raspberries
• Figs
• Kiwi
• Star fruit
• Grapes
• Plums
• Currants
• Dates

High-oxalate legumes:

• Soybeans
• Black beans
• Navy beans
• Kidney beans
• Lentils
• Peanuts
• Chickpeas

High-oxalate grains and cereals:

• Wheat bran
• Wheat germ
• Buckwheat
• Amaranth
• Rye
• Quinoa
• Barley
• Brown rice

High-oxalate snacks and sweets:

• Chocolate (dark and milk)
• Nuts (e.g., almonds, cashews)
• Peanut butter
• Tahini
• Soy products
• Miso
• Baked goods with high-oxalate ingredients
• Trail mix containing high-oxalate nuts and fruits

High-oxalate beverages:

• Black tea
• Green tea
• Soy milk
• Chocolate milk
• Certain fruit juices (e.g., cranberry, orange)
• Dark beers
• Certain herbal teas (e.g., hibiscus)

High-oxalate spices and seasonings:

• Cinnamon
• Ginger
• Pepper
• Turmeric
• Curry powder
• Paprika
• Soy sauce

High-oxalate nuts and seeds:

• Almonds
• Cashews
• Hazelnuts
• Peanuts
• Sesame seeds
• Chia seeds
• Poppy seeds

‍