Oxalate nutrition is a confusing, frustrating and little known area of health. There is a lot of conflicting advice about oxalate. Some of this advice is inaccurate and some is blatantly harmful. Read on for research-based advice on supplements to reduce oxalates.
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Who Needs to Reduce Oxalates?
Before we dive into the oxalate supplement conversation, it is very important to understand who might need to reduce oxalate in the first place.
Oxalate may be a concern for people with calcium oxalate kidney stones. However, high urine calcium is the most common cause of kidney stones. But, if you have high urine oxalate on a 24-hour urine test, then oxalate should be addressed.
Oxalate is also a concern for people who have a very rare genetic disorder called primary hyperoxaluria. People with primary hyperoxaluria do not have an enzyme needed to break down oxalate, resulting in very high oxalate levels.
It should be noted that oxalate has not been well-studied in any other health condition including interstitial cystitis, arthritis, vulvodynia or autism. Some claim oxalate is the cause for numerous health conditions. This is simply not true and there is no data to back up the claim that a low oxalate diet will help these conditions.
Supplements to Reduce Oxalates
Calcium Supplements
Calcium supplements can reduce oxalates by reducing the absorption of oxalate in the intestine. However, calcium supplements are not ideal for most people with kidney stones.
Why? Calcium supplements are associated with a higher risk of kidney stones. Whereas calcium from food is associated with a lower risk of kidney stones. Calcium supplements seem to increase urine calcium more than calcium found naturally in food. (1) High urine calcium is the most common cause of kidney stones. Not high urine oxalate.
In some cases, especially for people who make oxalate stones as a result of bariatric surgery, inflammatory bowel disease or other intestinal problem, calcium supplements can be used safely to reduce oxalate. This is because urine calcium is usually normal and high oxalate is the primary cause of kidney stones. (2) Ask your dietitian what is best for you!
Vitamin B6 Supplements
Vitamin B6 (aka pyridoxine) converts glyoxalate to glycine in the liver. With vitamin B6 deficiency, glyoxalate can build up, which ultimately ends up as oxalate. It is easy to take this information and assume vitamin B6 supplements could help high oxalate.
In reality, these things are never that clear cut. Vitamin B6 deficiency is rare. It is found in a large variety of foods such as meat, fish, potatoes, fruits and other veggies. (3) It is easy to eat enough vitamin B6 from food. Eating more vitamin B6 than you need will not reduce oxalate. Your body will just get rid of extra vitamin B6. There is no association between vitamin B6 levels, vitamin B6 intake and kidney stones or urine oxalate. (4)
For most people with kidney stones or high oxalate, vitamin B6 supplements will probably not make a difference.
However, people with primary hyperoxaluria are different! They do not have the enzyme that converts glyoxalate to glycine. Because the cause of high urine oxalate is unique, treatment is different. Vitamin B6 supplementation may help lower oxalates for people with primary hyperoxaluria. (5) Ask your dietitian what is best for you!
Magnesium Supplements
Magnesium definitely plays a role in kidney stones. People with kidney stones tend to have lower magnesium levels. (6) We know that magnesium and oxalate like to bind. When oxalate binds with magnesium, it is unable to bind with calcium and make a kidney stone.
However, magnesium supplements do not seem to consistently prevent kidney stones. (7) (8) A few small studies have found lower urine oxalate with magnesium supplements. (9) (10) We need more research to know who magnesium supplements could help prevent kidney stones and lower oxalates.
More about magnesium and kidney stones.
Fish Oil Supplements
There is some promising research on fish oil supplements and oxalates. One small study found that fish oil supplements can reduce oxalates in people who were eating a moderate amount of oxalate. (11) However, another study found that fish oil did not reduce oxalates for people on a low oxalate diet. (12)
In 2020, an analysis of all research available concluded that fish oil can help treat calcium oxalate kidney stones for people with high urine oxalate. (13)
I recommend Nature Made* fish oil supplements if you choose to use them to lower oxalates. This supplement has a USP verification and enough EPA and DHA to reduce oxalates.
Probiotic Supplements
There is a lot of research going on right now to see if probiotic supplements can reduce urine oxalates and help prevent kidney stones. The gut microbiome, kidney stones and oxalate metabolism are clearly linked. (14)
Unfortunately, trials to see if probiotics can reduce oxalates or prevent kidney stones have been mixed. Some animal trials have found that probiotic supplements can reduce oxalates. But, results in humans are varied and temporary. (14) (15) Chances are, the best way to support a healthy gut microbiome to prevent kidney stones is to eat a diet rich in fiber, whole grains, fruits and vegetables. We need more research before I can make a recommendation for probiotic supplements to reduce oxalates.
Supplements That Can Make Oxalate Worse
Turmeric Supplements
Turmeric is very high in oxalate. Supplemental turmeric is a very concentrated form of turmeric, and is therefore likely incredibly high in oxalate. Turmeric supplements should be avoided for people with high urine oxalate.
Of note, I am rarely concerned about using turmeric (or any other spice!) in cooking. Realistically, the amount of oxalate you get from a tablespoon(ish) of turmeric in your entire pot of curry (or other dish!) is minimal.
Cinnamon Supplements
Cinnamon is also very high in oxalate. Similar to turmeric, cinnamon supplements are a very concentrated source, and are probably very high in oxalate. Cinnamon supplements should be avoided for people with high urine oxalate.
Just like turmeric, the amount of oxalate you get from eating cinnamon is minimal and is not concerning.
“Superfood” Powders and Pills
Any type of “superfood” supplement is also potentially very high in oxalate. Many of these are made from powered vegetables. The vegetables in these supplements tend to be very high oxalate choices. For example, spinach is a common ingredient in these products, which has about 7x more oxalate per serving than any other food.
It is much better to actually EAT your fruits and vegetables than get them from a pill or powder anyway!
Vitamin C Supplements
Your liver can make oxalate from a few different things, including excess protein, fructose and vitamin C (aka ascorbic acid). Vitamin C supplements have been shown to significantly impact the amount of oxalate in urine. They should be avoided for anyone with high urine oxalate. (15)
It seems like vitamin C is in everything these days! It might be hiding in your orange juice, cough drops and immune supporting vitamins. Make sure to check those labels!
Never fear, it is easy to get enough vitamin C from food. One orange or bell pepper has nearly your entire days recommendation for vitamin C. Eating a balanced diet with plenty of fruits and vegetables nearly guarantees enough vitamin C.
Of note, vitamin C in FOOD should not be limited for people with high oxalate. In fact, foods with vitamin C tends tend to be very GOOD for kidney stone prevention. Vitamin C is highest in many fruits and vegetables. People who eat more fruits and vegetables tend to have fewer kidney stones. (16) (17)
Protein Supplements
Your liver can also make oxalate from extra protein. However, the impact of protein on urine oxalate is relatively small. (15)
Most people are eating more protein than they need. Protein powder or supplements often just add even more unnecessary protein, which could have a small impact on oxalate. More concerning, that extra protein could reduce urine citrate, reduce urine pH and increase urine calcium. All of these things could increase risk of calcium oxalate kidney stones. (2)
Everyone has different protein needs! Ask your dietitian how much protein is right for you, and if you are eating too much.
How Can I Reduce Oxalates?
Now that you know the options for supplements to reduce oxalates are limited. What can you do?
Again, reducing oxalate is only a concern for people who have high urine oxalate on a 24-hour urine test.
Eat Enough Calcium
The most effective way to lower urine oxalate is to make sure you eat enough calcium. Calcium can reduce how much oxalate is absorbed in the intestines. (2) Eating enough calcium can reduce the risk of calcium oxalate stones by 50%. (18)
Most people with kidney stones should eat 1,000-1,200mg calcium per day. (19) Learn more about the best sources of calcium for kidney stones.
Check out my cookbook full of high calcium recipes, just for people with calcium oxalate kidney stones!
Avoid Excess Protein
Your liver can make oxalate from extra protein. Although the impact of excess protein on oxalate is small, it does have an impact. More importantly, too much protein can increase urine calcium, reduce urine pH and reduce urine citrate. (2)
Excess protein, especially from foods like meat, chicken and fish, has been linked to a higher risk of kidney stones. (19)
Learn more about protein and kidney stones.
Avoid Very High Oxalate Foods
For most people, eating enough calcium is enough to lower urine oxalate to a safe range. However, some people have stubborn urine oxalate that will just not go down!
In this situation, it is recommended to cut back how much oxalate you eat. (18) The best way to do this is limit foods very high in oxalate. These foods include:
- Spinach & Swiss Chard
- Navy Beans
- Raspberries
- Rhubarb
- Potatoes
Grab my complete oxalate food list!
Join Kidney Stone Nutrition School!
Perhaps this article just left you more confused about oxalates and what you can do to prevent kidney stones.
Ultimately, nutrition to reduce oxalates and prevent kidney stones is different for every single person. There is no single kidney stone diet. Nutrition must be personalized to your 24-hour urine test and type of kidney stone.
I’d love to help you stop those kidney stones and living in fear of everything you eat! I do this every day with a personalized, evidence-based approach in Kidney Stone Nutrition School! Hope to see you there.
Happy Eating!
Melanie
Hi right now I was told I have a 2mm kidney stone in me. Besides drinking plenty of water, which i don’t like the taste. Please can you give me any other advice, thank you.
Oh no. I’m so sorry to hear that! Nutrition is all about preventing stones from forming in the first place – and stopping stones you have from getting any bigger. To know what you can do, you really need to get a 24 hour urine test to better understand your urine chemistry and what is “off”. Here is a post to learn more!
Hi! Came across a website called Kidneycop. They reportedly have a “well researched” supplement that prevents calcium oxakate stones. Is this true or just marketing hype? It is so hard to know what to trust. Really appreciate your work!! Thank you!
There are a ton of stone supplements like this. Essentially they are all just large doses of alkali/citrate – which may be beneficial for some, but actually harmful for others. Dr. Coe, a previous colleague of mine at the University of Chicago has written a comprehensive review of products like this, including Kidneycop.
Thank you!!
Hi again. What can you tell me about nutritional yeast (aka “nootch”) and its impact on kidney stones formation? Nootch (and other forms of yeast in general) contains purines, which can get converted to uric acid, and too much uric acid can result in uric acid kidney stones. Or so I’ve heard. How much nootch per day is too much for uric acid kidney stone sufferers? (I’m only talking about non-fortified nootch here).
Nutritional yeast is relatively high in purines which do get converted to uric acid. However, a low urine pH is really the primary driver of uric acid stones (now high uric acid). Not that high uric acid levels don’t matter. The amount that is ok for you really depends on that rest of foods you eat and your urine risk factors, so I can’t even venture a guess for you!
Thanks. My urine uric acid level was 4 at my last test a year ago (which I understand is on the low end of normal) and my urine pH has varied between 7 and 7.5 over the past 5 years. So, it would seem that I’m in pretty good shape, at least as far as those indicators go!