If you have chronic kidney disease (CKD) and have been questioning oxalates, you are not alone. Oxalates are one of the bigger questions I receive when working with individuals and not everyone with CKD needs to limit oxalates. A high oxalate food list is included for those that may need to monitor oxalate intake.
What are oxalates
Oxalate, or oxalic acid, is a compound that is naturally occurring in foods, specifically foods from plant sources.
Function of oxalates
Oxalate does not have a direct function in the body. However, within plants, oxalate is often bound to other minerals like calcium. Oxalate does have a high affinity or attraction to calcium, meaning oxalate will bind to calcium when conditions are right. For many individuals, the oxalate in the diet does not greatly impact the oxalate levels in the body as much of the oxalate binds to calcium in the intestine and is eliminated with a bowel movement.
Who should avoid oxalates
Not everyone needs to limit oxalates in their diet. However, some do. Let’s take a closer look at who should consider limiting dietary oxalates.
Testing for oxalates
The best way to assess oxalate levels for those with CKD is a 24 hour urine collection. Oxalate levels in the 24 hour urine collection give an idea of how much the kidneys are having to work to eliminate oxalate from the blood. This testing is involved and is not for those that do not have a history of kidney stones or CKD.
Kidney disease and oxalates
Not everyone with kidney disease will have a 24 hour urine collection completed regularly. The test is tedious and there is a lot of room for error in either over collecting urine or under collecting urine for that 24 hour time period. If the doctor is ordering a 24 hour urine to test for kidney function and you are interested in the oxalate levels, you can ask for them to test for it, but it is not a reason to test oxalate levels simply because of a CKD diagnosis.
Kidney stones and oxalates
Individuals with a history of kidney stones and especially those with a history of calcium oxalate (CaOx) stones will likely have a 24 hour urine test completed. Not everyone with a history of CaOx stones needs to limit oxalate. As mentioned earlier, calcium and oxalate have a strong bond. Pairing calcium rich foods with moderate oxalate foods can cause the oxalate in the foods to bind to the calcium in the gut and not be absorbed and impact the kidneys. The first line recommendations for individuals with history of CaOx stones is not to limit oxalate but first to (1):
- Hydrate: consume enough water to produce at least 2.5 liters of urine per day
- Reduce sodium intake: limit to less than 2,300mg per day
- Adequate Calcium Intake: consume 1,000-1,200mg calcium per day from food sources, not supplements.
How to cut back on oxalates
High oxalate food list
Spinach and almonds are two of the most commonly referred to foods for being high in oxalates, but they are not the only foods high in oxalate. Other foods high in oxalate include
- Beets (including beet greens)
- Navy bean
- Black Beans
- Chard (including rainbow and Swiss)
If you are unsure if cutting back on oxalates is for you, feel free to schedule an introductory call to see if we are a good fit to work together.
Other common questions and food swaps
Is coffee high in oxalates
Coffee is NOT high in oxalates! The additives to your coffee could be high in oxalates. Almond and cashew milk will be higher in oxalates than other options like oat or coconut milk.
Is kale high in oxalates
NO! Kale is not high in oxalates. Kale is a great alternative to spinach as it is far lower in oxalate than other greens.
Learn more about other diet myths that can impact kidney disease care.