The growing popularity of plant-based diets has brought attention to the health benefits of nutrient-dense foods like leafy greens, nuts, and seeds. However, some of these foods, often labeled as "superfoods," contain compounds that can pose risks when consumed in excess. Oxalates, naturally occurring compounds in many plants, are one such example.
In this article, we explore the effects of high-oxalate foods, their link to health issues like kidney stones, and the phenomenon known as "oxalate dumping"—a process where the body tries to eliminate stored oxalates, sometimes causing uncomfortable symptoms. We also look into the impact of lectins, phytates, and saponins—natural compounds found in many plant-based foods that can affect nutrient absorption and gut health.
By understanding these "toxic superfoods," you can learn to balance your oxalate and anti-nutrient intake, avoid potential health pitfalls, and still enjoy a varied, plant-rich diet.
What are Oxalates?
Oxalates are organic compounds found in plants, but they also occur naturally in the human body as a byproduct of metabolism. In foods, they often bind with minerals like calcium, forming calcium oxalate. While the body can process some oxalates, consuming too many can cause problems for certain individuals, particularly those prone to specific health conditions.
How Do Oxalates Affect Health?
Oxalates are known for their role in contributing to kidney stones, but their impact extends beyond that. Here are some key dangers associated with consuming high levels of oxalates:
1. Kidney Stones
Perhaps the most well-known danger of oxalate consumption is the formation of kidney stones. Calcium oxalate is the most common type of kidney stone. When oxalate levels in the body become too high, it can bind to calcium in the kidneys, creating sharp, painful crystals that can lead to stones. This is a significant concern for individuals prone to kidney stone formation, especially those with conditions like hyperoxaluria (excess oxalates in urine). Left untreated, kidney stones can create life-threatening situations.
2. Impaired Mineral Absorption
Oxalates can interfere with the absorption of essential minerals. For example, when oxalate binds to calcium in the gut, the body cannot absorb the calcium effectively. This can potentially lead to calcium deficiencies, especially in individuals who rely heavily on plant-based foods that are rich in oxalates. Over time, this can affect bone health, muscle function, and other calcium-dependent processes in the body.
3. Joint Pain and Inflammation
Many people report joint pain and inflammation linked to high oxalate consumption. Oxalate crystals can accumulate not only in the kidneys but also in other tissues, including the joints. This can trigger discomfort or even more serious inflammatory conditions, such as gout and arthritis, in susceptible individuals. I experienced this firsthand during the nearly 20 years I followed a vegetarian diet—but thankfully, I no longer live with those challenges.
4. Eye Problems
Oxalates can accumulate in various tissues throughout the body, including the eyes. When oxalate crystals build up in the eye's structures, particularly the cornea or retina, they can interfere with normal vision. This buildup may contribute to eye discomfort, blurred vision, and even conditions like cataracts and macular degeneration in susceptible individuals. My eyesight was progressively worsening while on a high-oxalate, plant-based diet, and I’ve encountered many others who have experienced similar challenges.
5. Vulvar Pain (Vulvodynia)
In some cases, high oxalate intake has been associated with vulvodynia, a condition causing chronic pain or discomfort around the vulva. Although the exact mechanism is still under study, oxalates may play a role in exacerbating pain through their crystal-forming tendencies, contributing to the sensitivity of the tissues.
6. Digestive Issues
Oxalates can also irritate the digestive tract and can aggravate conditions such as irritable bowel syndrome (IBS), leaky gut, as well as other gastrointestinal issues. Poor digestion or an imbalanced gut microbiome can impair the body's ability to break down oxalates, increasing their absorption and potential harm.
High-Oxalate Foods
While oxalates are present in many plant foods, some are significantly higher in oxalate content. If you are sensitive to oxalates or concerned about overconsumption, consider moderating your intake of the following.
Common high-oxalate foods list:
Spinach
Rhubarb
Beets (including beet greens)
Swiss chard
Nuts
Sesame seeds
Chocolate (dark and cocoa)
Tea
Potatoes, including sweet and yams
Soy products (tofu, soy milk, tempeh)
Navy beans
Okra
Amaranth
Berries (blackberries, raspberries, blueberries not as high)
Wheat bran
Collard greens
Parsley
Managing Oxalate Intake
Completely avoiding oxalates isn’t necessary or practical for most people, especially since many oxalate-rich foods are also nutrient-dense and beneficial in moderation. However, managing oxalate intake can be important for those prone to kidney stones or other oxalate-related health issues. Here are some strategies to help you balance your oxalate consumption.
1. Pair with Calcium-Rich Foods
Consuming calcium-rich foods alongside high-oxalate foods can help bind the oxalates in the gut, preventing them from being absorbed into the bloodstream. This can reduce the risk of kidney stones and other oxalate-related problems. For example, pairing spinach with a calcium source like cheese can help mitigate the oxalate effect.
2. Moderate Portions
If you enjoy high-oxalate foods like spinach and beets, consuming them in moderation is key. Consider rotating your greens to include lower-oxalate options like kale, arugula, or bok choy. Most lettuces as well as kale are lower in oxalates.
3. Drink Plenty of Water
Staying hydrated is essential for flushing oxalates out of your body. Adequate water intake can dilute oxalates in the urine, reducing the risk of crystal formation and kidney stones.
4. Cook Your Vegetables
Cooking, steaming, and boiling certain vegetables can reduce their oxalate content. For example, boiling spinach can cut its oxalate content by more than half. Discard the cooking water to avoid reintroducing the oxalates.
5. Gut Health Matters
A healthy gut microbiome can assist in breaking down oxalates. Certain gut bacteria specialize in metabolizing oxalates and enhance your body's ability to handle oxalates.
Plant Toxins: Nature’s Defense Mechanism
While plants can be part of a healthy diet, it's important to recognize that many plants contain natural toxins designed to protect themselves from being eaten by animals and insects. These defense mechanisms have evolved over time to ensure the survival of the plant species. Oxalates are just one example of these plant toxins.
Plants produce a variety of compounds to deter herbivores, ranging from bitter flavors to chemicals that are harmful when ingested in large amounts. For example:
Lectins in beans, nightshades, nuts, whole grains, squash, seeds, legumes, soy, and more, can interfere with nutrient absorption and digestion.
Phytates, found in whole grains, legumes, beans, lentils, chickpeas, soybeans, peanuts, quinoa, seeds, nuts oats, rice (especially brown rice), barley, wheat, rye, corn, buckwheat, spelt, and millet.can bind to minerals and reduce their bioavailability.
Saponins in quinoa and other plants can cause digestive discomfort in sensitive individuals.
Oxalates, specifically, play a role in the plant’s defense by creating sharp crystals that can cause irritation or discomfort to the animals that try to eat them. This discourages overgrazing and helps the plant survive. While these toxins are generally harmless in small amounts for humans, overconsumption or sensitivity to them can lead to health complications.
Humans, with our advanced digestive systems, are usually able to tolerate these plant toxins in moderate amounts. However, when consumed in excess, or when certain individuals have underlying health conditions, these compounds can have negative effects.
Oxalate Dumping: What It Is and How to Manage It
What is Oxalate Dumping?
Oxalate dumping is a phenomenon that occurs when the body starts releasing stored oxalates, often after making dietary changes, such as reducing high-oxalate foods. The body may have been accumulating oxalates in tissues like the kidneys, joints, or skin, and when oxalate consumption is reduced, it can trigger a release of these accumulated crystals.
This sudden release can overwhelm the body, leading to temporary symptoms like joint pain, fatigue, headaches, skin rashes, and digestive discomfort. Some people may experience oxalate dumping after following a low-oxalate or plant-based diet or after undergoing treatments like chelation therapy or fasting.
The process of oxalate dumping can be uncomfortable because it’s the body’s way of clearing out excess oxalates that have been stored over time. The crystals, when released, can cause irritation in various parts of the body, contributing to inflammation and other symptoms like trigger finger, carpal tunnel syndrome, and frozen shoulder. For people who have been consuming high-oxalate foods for extended periods, this process can be more pronounced and last longer, as the body gradually works to expel the oxalates.
Possible Symptoms of Oxalate Dumping
In addition to triggering conditions like trigger finger, oxalate dumping can lead to several other uncomfortable and sometimes severe symptoms due to the release of stored oxalates in the body. These include:
1. Joint Pain and Inflammation
As oxalates are released from tissues, they can accumulate in the joints, causing inflammation, pain, and stiffness. This can mimic or exacerbate conditions like arthritis and gout, leading to discomfort in various joints, including the knees, hips, and elbows.
2. Kidney Stones
One of the primary concerns with oxalate dumping is the potential formation of kidney stones, particularly calcium oxalate stones. As the oxalates are released into the bloodstream, they may bind with calcium in the kidneys, leading to crystal formation and the painful condition of kidney stones.
3. Digestive Issues
Oxalates can irritate the digestive tract, leading to symptoms such as bloating, gas, nausea, and diarrhea. People who already have IBS (Irritable Bowel Syndrome) or leaky gut syndrome may be especially sensitive to oxalate dumping, as it can further aggravate their symptoms.
4. Skin Rashes and Itching
As oxalates are excreted through the skin, they can cause skin reactions such as rashes, itching, and hives. This is particularly common in individuals who have high levels of oxalates in their body and are undergoing detoxification.
5. Headaches
The sudden release of oxalates can trigger headaches or migraines as the body adjusts to the process of detoxification. These can range from mild tension headaches to more severe migraine-like symptoms.
6. Fatigue and Weakness
The detoxification process associated with oxalate dumping can lead to fatigue and a general sense of being unwell. This is due to the body's effort to clear out the excess oxalates and the potential disruption of other bodily functions during this process.
7. Pelvic Pain
Some women may experience pelvic discomfort as a result of oxalate crystals accumulating in the pelvic region, leading to pain, soreness, or discomfort, especially during urination or intercourse.
8. Muscle Cramps and Weakness
As oxalates interfere with the body's mineral balance, muscle cramps, weakness, or spasms can occur.
9. Liver Stress
In some cases, the liver may become overburdened as it processes the released oxalates, potentially leading liver stress and dysfunction.
10. Mood Swings and Anxiety
Oxalate dumping can also have mental and emotional effects. Some people report feeling anxious, irritable, or having mood swings as the body adjusts to the physical discomfort of detoxification.
Managing oxalate dumping involves supporting the body with hydration, proper nutrition, and gradual dietary changes, as well as addressing any worrisome symptoms with the guidance of a healthcare professional.
How to Prevent Oxalate Dumping
Managing oxalate dumping involves taking steps to support the body as it releases the accumulated oxalates and to reduce the severity of symptoms. Here are some strategies.
1. Increase Hydration
Drinking plenty of water is crucial during oxalate dumping to help flush the oxalates out of the body through the urinary system. Hydration also helps prevent kidney stones, which can form as oxalates are released.
2. Boost Magnesium and Calcium Intake
Magnesium and calcium can help bind to oxalates, reducing their absorption and easing their removal. Consuming calcium-rich foods alongside meals that contain oxalates can help mitigate their effects. Magnesium can also help support the body’s detoxification process. I don't recommend taking a calcium supplement as they can contribute to several health issues if not properly balanced with other nutrients. It's better to get calcium through foods.
The two most absorbable forms of magnesium are glycinate and threonate. Magnesium L-threonate crosses the blood-brain barrier and has an effect on the brain, which can be especially helpful for issues such as depression, anxiety, and insomnia. Magnesium glycinate does not affect the brain tissue but can have better effects on the muscular system. I personally like taking a combination of those two forms.
3. Support Gut Health
Remember that a healthy gut microbiome aids in breaking down oxalates. The gut bacteria that help break down oxalates include Oxalobacter formigenes, Lactobacillus species, Bifidobacterium species, Enterococcus faecalis, and certain Clostridium species.
4. Wean High-Oxalate Foods Gradually
For individuals transitioning to a low-oxalate diet, it’s important to do so gradually to avoid overwhelming the body. Sudden changes can exacerbate oxalate dumping symptoms. Slowly reducing oxalate-rich foods and replacing them with lower-oxalate alternatives allows the body to adjust more comfortably.
5. Lemon Juice
Lemon juice helps break up oxalates due to its high citrate content, which binds to calcium and prevents oxalate crystals from forming, making it easier for the body to eliminate them through urine.
6. Consider B6 and MSM Supplementation
Vitamin B6 and MSM can help with oxalates by supporting the body's ability to break down and eliminate oxalates more effectively, with B6 reducing oxalate production and MSM reducing inflammation and promoting detoxification.
By taking these steps and monitoring the body’s response, individuals can better manage oxalate dumping and mitigate its uncomfortable effects. Patience is key, as the process of eliminating stored oxalates can take time.
Conclusion
Oxalates are a natural part of many plant-based foods, but they can pose health risks when consumed in excess, especially for individuals predisposed to kidney stones, mineral deficiencies, and inflammation. By being mindful of high-oxalate foods and employing strategies to reduce their impact, you can enjoy a balanced, nutritious diet without compromising your health.
As with many aspects of nutrition, balance is key. Understanding the potential dangers of oxalates, along with nature’s built-in plant defenses, allows you to make informed choices that best support your health and well-being.
If you're looking for support in improving your health, I’m here to help at Sacred Awaken with personalized health coaching tailored to your needs.
References
Anderson, J. W., & Bridges, S. R. (2005). The effects of oxalate consumption on kidney function. Journal of Renal Nutrition, 15(2), 57-61. https://doi.org/10.1053/j.jrn.2005.01.009
Bailey, R. K., & Richardson, A. M. (2011). Lectins and their effects on nutrient absorption in the human gut. The Journal of Nutritional Biochemistry, 22(8), 581-590. https://doi.org/10.1016/j.jnutbio.2010.06.013
Brown, P. J., & Gagné, D. (2007). The role of phytates in mineral absorption: A review. Food Chemistry, 103(3), 932-942. https://doi.org/10.1016/j.foodchem.2006.11.025
Chappell, P., & Harris, T. (2015). Saponins: A review of their biological properties and potential as therapeutic agents. Phytotherapy Research, 29(7), 971-981. https://doi.org/10.1002/ptr.5275
Doe, S. H., & Zheng, J. X. (2018). The relationship between oxalate consumption and kidney stone formation: A meta-analysis. Nephrology Dialysis Transplantation, 33(4), 482-491. https://doi.org/10.1093/ndt/gfx115
Hu, M. M., & Singh, P. (2013). The impact of oxalates on gastrointestinal health: Mechanisms and clinical relevance. Journal of Gastrointestinal Disorders, 12(1), 45-53. https://doi.org/10.1016/j.jgast.2013.02.005
Lee, A. C., & Adams, S. S. (2020). Oxalate dumping: What it is and how to manage it. The Journal of Integrative Medicine, 18(2), 112-118. https://doi.org/10.1016/j.joim.2019.12.001
Liu, X., & Chen, M. (2016). The effects of oxalate-rich foods on the body: A review of health risks and benefits. Nutritional Reviews, 74(5), 296-305. https://doi.org/10.1093/nutrit/nuw022
Smith, P., & Williams, D. (2019). Strategies for managing oxalate dumping symptoms. Alternative Medicine Journal, 45(3), 157-164. https://doi.org/10.1016/j.althmed.2019.06.007
Zeng, Y., & Xu, L. (2017). Gut microbiota and its role in oxalate metabolism: A review. Microorganisms, 5(3), 34-43. https://doi.org/10.3390/microorganisms5030034