Oxalates, though naturally occurring in many foods and produced by the body, have gained increasing attention for their potential role in various chronic conditions. From kidney stones to musculoskeletal pain, oxalates can have a wide range of impacts, especially in individuals with underlying gut issues or metabolic dysfunction. This guide will cover what oxalates are, sources, symptoms, and comprehensive approaches to managing oxalate overload.

What Are Oxalates?

Dietary oxalate refers to oxalic acid and its salts (oxalates), which occur naturally in many plants. Oxalic acid can bind with minerals like calcium, sodium, or potassium to form oxalate salts such as calcium oxalate. While small amounts of oxalates are generally harmless and eliminated through stool or urine, excessive accumulation can lead to the formation of crystals, resulting in various health issues.

Sources of Oxalates: Exogenous and Endogenous

Oxalates come from two primary sources: exogenous (dietary) and endogenous (internal) production. Understanding these sources is key to managing oxalate levels effectively.

1. Exogenous (Dietary) Oxalates

Dietary oxalates are introduced into the body through the consumption of high-oxalate foods, primarily plant-based. Some of the most common dietary sources of oxalates include:

• Spinach: Over 750 mg of oxalates per cup (cooked).
• Rhubarb: Contains between 500–1000 mg per half cup.
• Almonds: 122 mg of oxalates per 30 grams.
• Sweet Potatoes: About 150 mg of oxalates per medium potato.
• Swiss Chard: Ranges from 500–900 mg of oxalates per half cup.
• Chocolate and Cocoa: Significant sources of oxalates often overlooked.

It is important to note that dietary oxalates contribute approximately 10% of the total oxalate load in the body under normal circumstances. Rather than obsessively removing all oxalates from the diet, it is more practical to manage oxalate levels through moderation, balancing oxalate-rich foods with others, and—most importantly—addressing the underlying causes of oxalate overload.

2. Endogenous (Internal) Oxalate Production

The body can produce oxalates internally through various metabolic processes, primarily in the liver and also through the action of certain microorganisms. This endogenous production is a critical aspect to consider, particularly for individuals with gut dysbiosis, metabolic disorders, or yeast overgrowth.

• Liver and Glyoxylate Pathway: The liver is a key site for oxalate production. Glyoxylate, a precursor to oxalate, can either be converted into oxalate or into less harmful compounds like glycine. Deficiencies in enzymes that regulate this pathway, as seen in conditions like primary hyperoxaluria, can lead to excessive oxalate production.

• Yeast and Fungal Overgrowth: Yeast species like Candida and Aspergillus can produce oxalates as part of their metabolic processes. This type of oxalate production is considered endogenous because it originates from organisms within the body. Individuals with chronic yeast or fungal overgrowth may experience elevated oxalate levels due to this internal source. Addressing these infections can reduce oxalate production and alleviate related symptoms.

• Dietary Influence on Endogenous Production: Certain dietary components can also influence the internal production of oxalates. For example, excess vitamin C can be metabolized into oxalate, and high consumption of collagen or gelatin (due to their hydroxyproline content) can increase oxalate production.

By understanding the interplay between exogenous and endogenous sources of oxalates, individuals can tailor their approach to managing oxalate levels effectively, addressing both dietary intake and internal production.

Symptoms of Oxalate Overload

Oxalate overload, whether from diet or internal production, can cause a variety of symptoms, many of which overlap with other chronic health conditions. Common symptoms include:

• Musculoskeletal Pain: Joint pain, muscle soreness, and fibromyalgia-like symptoms. The deposition of calcium oxalate crystals in soft tissues is thought to exacerbate this pain.
• Kidney Stones: Calcium oxalate kidney stones are the most common type and form when high levels of oxalates bind with calcium in the kidneys.
• Fatigue and Brain Fog: High oxalate levels can interfere with energy production and cognitive function, leading to chronic fatigue and difficulty concentrating.
• Gastrointestinal Issues: Bloating, cramping, and digestive discomfort are common when oxalates irritate the gut lining, particularly in individuals with “leaky gut” or inflammatory bowel conditions.
• Urinary Symptoms: Painful urination, frequent urination, or blood in the urine may indicate kidney involvement with oxalates.
• Thyroid and Soft Tissue Calcification: In some cases, calcium oxalate crystals deposit in soft tissues, including the thyroid, potentially leading to calcifications that disrupt normal function.

Causes of Elevated Oxalates

Several factors contribute to elevated oxalate levels in the body. Identifying and addressing all factors helps to effectively eliminate the problem.

1. Dietary Sources of Oxalates

Many healthy plant-based foods contain high levels of oxalates. However, as already mentioned, dietary oxalates only contribute approximately 10% of the total oxalate load in the body. For those with high oxalate levels, it’s more effective to balance these foods in the diet rather than avoiding them completely.

2. Fat Malabsorption

Fat malabsorption plays a significant role in increasing systemic oxalate absorption. Normally, calcium binds to oxalates in the gut, preventing their absorption. However, when fats are not properly absorbed—such as in conditions like SIBO, celiac disease, or pancreatic insufficiency—the unabsorbed fats bind to calcium instead, leaving oxalates free to be absorbed into the bloodstream.

3. Microbiome Imbalances

The gut microbiome plays an essential role in breaking down oxalates. Certain bacteria, particularly Oxalobacter formigenes, can degrade oxalates in the intestines, preventing their absorption.

4. Small Intestinal Bacterial Overgrowth (SIBO)

One of the most significant causes of oxalate overload in the body is Small Intestinal Bacterial Overgrowth (SIBO). SIBO occurs when bacteria that typically reside in the colon begin to thrive in the small intestine. This overgrowth disrupts normal digestion and interferes with nutrient absorption, particularly fats. In individuals with SIBO, bacterial overgrowth can deconjugate bile salts, preventing them from properly breaking down fats. When fats aren’t absorbed properly, they bind to calcium in the gut, making it unavailable to bind with oxalates. This unbound oxalate is then free to be absorbed into the bloodstream, contributing to the systemic issues seen with oxalate overload.

5. Yeast and Fungal Overgrowth

Some yeast or fungal species like Candida and Aspergillus can produce oxalates during their metabolic processes. Individuals with chronic yeast or fungal overgrowth may see elevated oxalate levels as a result. In these cases, treating the underlying fungal infection can help reduce oxalate production.

Testing for Oxalates in the Urine

• Organic Acids Test (OAT): This test is often the most reliable for detecting oxalate levels in individuals presenting with symptoms like pain and kidney stones. It measures oxalate metabolites and can indicate whether Candida or Aspergillus species (yeast and fungi) are contributing to oxalate production. The OAT test can also provide insight into metabolic dysfunctions that lead to endogenous oxalate production. Check Functional Testing find out more about OAT test.
• Conventional Urinary Oxalate Tests: Conventional lab tests may not always pick up elevated urinary oxalates, especially in individuals with fat malabsorption or microbial imbalances.
• Stool Analysis: Digestive stool analysis is a valuable tool for understanding the underlying causes of oxalate issues. It identifies fat malabsorption, microbiome dysfunction, SIBO, or other pathogenic overgrowths that may contribute to increased oxalate absorption.

Approaches to Managing Oxalate Overload

Managing oxalate overload requires a multi-faceted approach that addresses both dietary intake and the underlying conditions that contribute to high oxalate absorption or production.

1. Dietary Changes: Reducing Oxalate Intake Gradually

While reducing dietary oxalates can help manage symptoms, it’s important to do so gradually. Sudden reductions can lead to oxalate dumping, where stored oxalates are released from tissues into the bloodstream, worsening symptoms.

Focus on reducing the highest oxalate foods first, such as spinach, almonds, and rhubarb, and balance them with calcium-rich foods like broccoli or dairy products, which can help bind oxalates in the gut.

2. Calcium and Magnesium Supplementation

Calcium and magnesium can help reduce oxalate absorption by binding with oxalates in the gut, allowing them to be excreted in stool rather than absorbed into the bloodstream. Taking calcium supplements with meals is particularly effective.

3. Support Fat Digestion and Absorption

Improving fat digestion is essential for reducing oxalate absorption in individuals with fat malabsorption. Digestive enzymes and bile salts can help improve the breakdown of fats, reducing the amount of unbound oxalates that are absorbed. Supporting bile flow with nutrients like taurine, glycine, and cholagogue herbs is also beneficial.

4. Probiotics for Oxalate Degradation

Probiotic strains like Oxalobacter formigenes, Lactobacillus acidophilus, and Bifidobacterium breve can help degrade oxalates in the gut, reducing their absorption. Probiotic supplementation, along with a diet rich in fiber and prebiotics, can support a healthy gut microbiome.

5. Vitamin B6 Supplementation

Vitamin B6 is a critical cofactor in oxalate metabolism. It helps convert glyoxylate into glycine rather than oxalate, reducing the internal production of oxalates. Supplementing with pyridoxine hydrochloride can help lower oxalate levels, especially in individuals with low B6 status.

6. Addressing Yeast and Fungal Overgrowth

In cases where yeast or fungal overgrowth is contributing to elevated oxalate levels, addressing the infection is key. Antifungal treatments, combined with a low-sugar diet and probiotics, can help restore balance in the gut and reduce oxalate production.

Conclusion

Managing oxalate overload is complex and often overlooked factor in chronic health conditions like kidney stones, pain, and digestive issues. By understanding the sources of oxalates—both exogenous and endogenous—individuals can take practical steps to manage oxalate overload. Whether through dietary adjustments, supplementation, or addressing gut health, managing oxalates overload requires a comprehensive and individualized approach. Functional Testing, such as the Organic Acids Test or Digestive Stool Analysis provides valuable insights into oxalate levels and guides treatment strategies.

If you suspect that oxalates may be contributing to your symptoms, it’s important to work with a healthcare practitioner to develop a plan that addresses your unique needs and supports your body’s ability to manage oxalates overload effectively.

Oxalate Case Study

Mark 61, came to me with severe digestive problems: diarrhea, bloating, food intolerances, and low energy. He also had both shoulder bursitis, muscle pain, and a congested liver and lymphatic system. His diet was very limited—mostly potatoes, buckwheat, spinach, sprouted nuts, seeds, and hemp powder.

Comprehensive Digestive Stool Testing showed gut dysbiosis, poor microbial diversity, and high histamine producing pathogens. We started slowly rebuilding his gut and included lymphatic drainage every two weeks, which left him feeling drained due to a high toxic load.

Unfortunately, few months later Mark had hospital emergency visit due to kidney stones. This led me to suspect oxalate overload. Testing wasn’t necessary. Calcium stones together with SIBO, fat malabsorption, and high-oxalate diet was a perfect storm. I have managed oxalate overload with high dose of calcium/magnesium citrate and low-oxalate diet.

Within four weeks, Mark’s shoulder mobility improved, muscle pain eased, connective tissue softened, and his energy and digestion improved. This case illustrates how oxalate overload was an obstacle to recovery.