Oxalates are compounds found in a variety of plant-based foods that have gained attention in recent years. These naturally occurring substances have been the subject of much discussion due to their potential impact on health. Oxalates are known for their ability to form crystals, and when consumed in excess or by individuals who are more susceptible, they may contribute to the formation of kidney stones. Foods such as spinach, rhubarb, beets, and certain nuts and seeds are often cited as high-oxalate foods. However, it’s important to note that oxalates are not inherently harmful and can even have beneficial effects on the body. They play a role in plant defence mechanisms, as well as being involved in the metabolism of certain nutrients. You can read more about oxalates in general in a previous article we have written here.
How Are Oxalates Metabolised In The Human Body?
In the human body, oxalates are metabolized through various mechanisms to maintain balance and prevent excessive buildup. Understanding how oxalates are metabolized is essential for individuals concerned about their oxalate intake and the potential risk of kidney stone formation.
Upon ingestion, oxalates are absorbed from the digestive tract into the bloodstream. The majority of oxalates are then filtered by the kidneys and excreted in the urine. This renal excretion plays a crucial role in maintaining oxalate balance in the body.
In healthy individuals, the kidneys effectively remove oxalates through glomerular filtration and tubular secretion. However, in individuals with certain conditions, such as hyperoxaluria or compromised kidney function, the kidneys may have difficulty excreting oxalates efficiently. This can result in increased oxalate levels in the urine, which may contribute to the formation of kidney stones.
Some oxalates may also undergo metabolism in the liver. Oxalate metabolism involves the conversion of oxalate to a less harmful compound called glyoxylate through the action of liver enzymes. From there, glyoxylate can be further metabolized into other compounds or utilized in various biochemical pathways.
It’s important to note that the metabolism of oxalates can be influenced by several factors, including dietary intake, gut microbiota, and genetic variations. The gut microbiota, in particular, may play a significant role in oxalate metabolism. Certain types of bacteria in the gut can break down oxalates, reducing their absorption and potential for kidney stone formation.
Moreover, factors like gut health, gut motility, and overall diet composition can affect the balance between oxalate absorption and metabolism. A healthy gut, adequate hydration, and a well-rounded diet that includes calcium-rich foods can help maintain oxalate balance and minimize the risk of kidney stone formation.
Individual responses to oxalate metabolism can vary, and it’s essential to work with healthcare professionals, such as nephrologists or registered dietitians and naturopaths, to address any concerns and receive personalized recommendations based on your specific health conditions and needs.
Hyperoxaluria is a condition characterized by elevated levels of oxalate in the urine, which can increase the risk of kidney stone formation. There are two primary types of hyperoxaluria: primary hyperoxaluria, which is a rare genetic disorder resulting from enzyme deficiencies that impair oxalate metabolism, and secondary hyperoxaluria, which occurs due to underlying factors such as intestinal malabsorption, certain medications, or dietary factors.
Excess oxalate in the urine can combine with calcium to form crystals, leading to the development of kidney stones. Managing hyperoxaluria involves a comprehensive approach, including dietary modifications, increased fluid intake, and sometimes medication to reduce oxalate production or increase its excretion.
Oxalates & Kidney Health
When it comes to kidney disease, oxalates have gained attention as potential contributors to the formation of kidney stones, a common complication in individuals with compromised kidney function. Kidney stones are hard mineral and salt deposits that can form in the kidneys and cause significant pain and discomfort. Oxalate crystals can combine with calcium to form these stones, particularly when urine becomes highly concentrated or when there is insufficient fluid intake to dilute the urine.
For individuals with kidney disease, reducing the intake of high-oxalate foods is often recommended to help manage the risk of kidney stone formation. Foods such as spinach, rhubarb, beets, chocolate, and certain nuts and seeds are known to have higher oxalate content. Limiting the consumption of these foods can help decrease the overall oxalate load in the body.
It’s important to note that not all individuals with kidney disease need to completely avoid oxalates.
In addition to reducing oxalate-rich foods, other strategies to manage oxalate levels in individuals with kidney disease include increasing fluid intake to promote urine dilution, maintaining a balanced diet, and ensuring adequate calcium intake. Calcium can bind to oxalate in the digestive system, reducing its absorption and potential for crystal formation.
It’s worth noting that simply avoiding high-oxalate foods may not be sufficient to prevent kidney stones, as other factors such as genetics, urinary pH levels, and overall kidney health also play a role.
You can read more about oxalates and Kidney disease here.
Strategies To Reduce The Impacts of Oxalates on Kidney Health
Understand High-Oxalate Foods:
Educating yourself about foods that are high in oxalates is the first step towards managing your oxalate intake effectively. Some examples of high-oxalate foods include spinach, rhubarb, beets, Swiss chard, almonds, and dates. However, it’s important to note that oxalate content can vary even within food groups, so it’s essential to consider overall dietary patterns.
Opt for Moderation, Not Elimination:
Completely eliminating high-oxalate foods may not be necessary for everyone. Instead, focus on moderation and portion control. Enjoy these foods as part of a balanced diet while being mindful of overall oxalate consumption. Pairing high-oxalate foods with calcium-rich options can help bind oxalates in the digestive system, reducing their absorption.
Cooking and Food Preparation Techniques:
Certain cooking methods can help reduce the oxalate content in foods. For instance, boiling vegetables can leach out oxalates into the cooking water, making them a more suitable option for individuals with oxalate concerns. Discarding the cooking water can further minimize oxalate intake. Steaming and blanching are other methods that may help reduce oxalates.
Adequate Fluid Intake:
Staying properly hydrated is essential for diluting urine and preventing the concentration of oxalates. Aim to drink an adequate amount of fluids throughout the day, preferably water. Adequate hydration helps maintain overall kidney health and can minimize the risk of kidney stone formation.
Consider Oxalate Absorption Enhancers and Inhibitors:
Some studies suggest that incorporating foods high in soluble fibre, such as fruits, vegetables, and whole grains, may help lower the absorption of oxalates. Soluble fibre forms a gel-like substance in the digestive tract, which can bind to oxalates and inhibit their absorption into the bloodstream. By reducing the absorption of oxalates, the risk of their crystallization and subsequent kidney stone formation may be mitigated
Consuming probiotic-rich foods like yogurt and fermented products might also play a role in reducing oxalate absorption.
Pairing Oxalates With Calcium Rich Foods
Calcium has the ability to bind to oxalates in the digestive tract, preventing their absorption into the bloodstream and the subsequent formation of kidney stones. By consuming calcium-rich foods alongside oxalate foods, the likelihood of oxalate crystals forming and causing harm is minimized.
Here are some calcium-rich foods that can be included in your diet:
- Bok choy
- Canned tuna with bones
- Tofu (made with calcium sulphate)
- White beans
It’s important to note that obtaining calcium from whole foods is generally preferred over supplements, as whole foods often provide additional nutrients and are better absorbed by the body. When consuming high-oxalate foods alongside calcium-rich foods, it’s essential to maintain a balance between the two. Aim to include adequate amounts of calcium-rich foods in your diet, ideally with each meal or snack, while still practising moderation with high-oxalate foods.
Supplementing with Vitamin B6
Scientific studies suggest that certain interventions can help reduce oxalate levels in individuals with hyperoxaluria. One such intervention is the use of vitamin B-6, also known as pyridoxine. Vitamin B-6 plays a vital role in the metabolism of oxalate, and supplementation with this vitamin has been shown to decrease urinary oxalate excretion in individuals with primary hyperoxaluria type 1 (PH1), a genetic disorder characterized by impaired oxalate metabolism. Research has demonstrated that vitamin B-6 supplementation can effectively reduce urinary oxalate levels in PH1 patients and potentially prevent the formation of calcium oxalate kidney stones.
Personalized Approach and Professional Guidance:
Each individual’s oxalate tolerance can vary, and it’s important to consult with a healthcare professional, such as a registered dietitian, naturopath, or integrative medical practitioner.
Foods High In Oxalates
While oxalate content can vary within specific food items due to factors like cultivation practices and soil conditions, here is a comprehensive list of foods that are generally considered to be high in oxalates:
- Swiss chard
- Potato skins
- Black tea
- Nuts such as almonds, brazil nuts and pine nuts
It’s important to note that while these foods are higher in oxalates, they also offer various other nutritional benefits. Moderation and balance are key when incorporating these foods into your diet, especially if you have a history of kidney stones or concerns about oxalate intake.
Keep in mind that oxalate sensitivity can vary among individuals, and some people may tolerate high-oxalate foods without experiencing adverse effects.
It’s worth mentioning that individual needs and tolerances can vary, so it’s advisable to work with a healthcare professional, naturopath or integrative medical practitioner or registered dietitian to tailor dietary recommendations specific to your needs and to ensure the optimal balance between calcium and oxalate intake.
Understanding high-oxalate foods and adopting strategies to minimize oxalate intakes, such as moderation, cooking techniques, and fluid intake, can help reduce the risk of stone formation. Additionally, pairing high-oxalate foods with calcium-rich options can bind oxalates in the digestive system, further mitigating their absorption and potential harm.
It is crucial to maintain a balanced approach, considering individual needs and seeking professional guidance from healthcare providers, naturopaths, integrative practitioners or registered dietitians to tailor dietary recommendations to one’s specific condition.
By adopting these strategies and personalizing dietary choices, individuals with kidney disease can optimize their kidney health and minimize the risk of complications associated with oxalate-related kidney stone formation.