“Plants are toxic!” Are oxalates destroying your health?
On February 6th, 2024, Candi Frazier aka theprimalbod published an instagram reel making claims about the range of effects oxalates can have on our health, with the caption stating “Oxalates shouldn't be a big deal, but when you never take a break from them (i.e. you are not living in harmony with the seasonal cycles of vegetables), they may form crystals and eventually stones.”
Our analysis aims to evaluate the claims made in this post and identify whether oxalates are a cause for concern in your diet.
While high oxalate intake can contribute to kidney stones in susceptible individuals, most people excrete oxalates safely. The idea of "oxalate dumping" lacks scientific support, and plant foods are generally associated with a lower risk of kidney stones. Dr. David Goldfarb advises sufficient calcium in the diet and proper hydration, emphasising that most people do not need to avoid oxalate-containing foods.
Oxalates are found in many of the health-promoting foods you might eat regularly, it's important to understand how they impact your health, especially given all the claims made about them online!
Look for evidence: Reliable claims should be backed by scientific studies or data.
Recently, Candi Frazier, also known as The Primal Bod on Instagram, posted a reel claiming that oxalates in foods have harmful effects on our health. She made statements such as “Oxalates create a lot of inflammation in our body” and “They act like fiberglass in our tissue!”
What are oxalates?
Oxalates are naturally occurring compounds found in various foods, including leafy green vegetables, beans, and nuts. They are a component of certain types of kidney stones (calcium-oxalate stones). For most people, it’s safe to consume oxalate-containing foods, but those with a history of kidney stones or who are at risk may want to moderate their intake. Influencers are increasingly claiming that oxalate-rich foods are harmful and should be avoided.
Let’s fact-check the claims made by Candi Frazier.
Claim 1
“Your body will make calcium oxalate stones and they’ll deposit in your kidneys, but you can also have gallstones that are oxalate related, pancreas stones, tonsil stones. Any stones are typically from oxalate toxicity.”
Fact-check
This claim is misleading due to the certainty with which it is stated. While calcium oxalate kidney stones can form in some people who consume oxalates, most people safely excrete oxalates without forming stones. Factors such as the concentration of oxalate and calcium in the urine, urine volume, and the presence of other substances that may prevent or promote stone formation influence whether stones form.
Moreover, not all types of stones are typically caused by oxalates. For example, gallstones are primarily composed of cholesterol or bilirubin, and a diet high in fat or cholesterol can contribute to their development.
Claim 2
“Everyone is usually loaded in oxalates because you’ve been eating them for long periods of time.”
Fact-check
This claim is also misleading. Most people with normal kidney function, or even those with kidney stones, do not have high levels of oxalate in their blood. The body usually manages to excrete oxalate efficiently.
“This is in rare cases with people as a result of conditions such as primary hyperoxaluria, it’s highly unlikely to occur in individuals with healthy kidney function who are consuming oxalates in their diet, as you should just excrete it.”
Source: Oxalates & Kidney stones | Dr. David Goldfarb, MD | Nutrition Made Simple
Claim 3
“When you dump [oxalates], you’ll experience burning when you have a bowel movement, your skin will get really powdery, you’ll get what feels like sand coming out of the corners of your eyes, and in your nose, you’ll feel really tired, you could get join inflammation.”
Fact-check
This claim is not supported by scientific evidence. The idea of "oxalate dumping" and its associated symptoms primarily comes from anecdotal reports rather than research. There is no evidence in scientific literature to suggest that these symptoms occur as a result of reducing oxalate intake.
In his interview with Dr. Carvalho on Nutrition Made Simple, Dr. Goldfarb stated that he has not observed such effects in any of his patients and considers it highly unlikely in individuals with healthy kidney function.
Claim 4
“Oxalates are really high in spinach, in potatoes, sweet potatoes, chard like swiss chard, chocolate, tea, beets.”
Fact-check
It’s true that foods like spinach, potatoes and swiss chard contain high levels of oxalates, but this does not mean these foods should be avoided. Very few foods are super high in oxalates; they are mainly high in spinach and chard, while most foods, including other greens such as kale, are not. Consuming large amounts of spinach, particularly in forms like smoothies where you can ingest large volumes at once, can increase the intake of oxalates. But again, this doesn’t mean spinach isn’t safe to eat. Calcium intake is crucial, as it helps mitigate the risks associated with oxalates and kidney stones.
On the contrary to how the claims in Candi’s video can be viewed, plant foods are actually associated with lower risk of kidney stones. An analysis of 1,322,133 participants and 21,030 cases across different studies found that fruit, vegetable, and fibre consumption is associated with a lower risk, while meat consumption is associated with higher risk of kidney stones.
Dr. David Goldfarb, Nephrologist, MD said “More fruits and vegetables is generally good, a plant-based diet is a good idea for kidney stone prevention.”
Dr. Goldfarb’s Advice on Oxalates in the Diet
In his interview on Nutrition Made Simple, Dr Goldfarb, who is a double-board certified nephrologist and internal medicine specialist, and responsible for running the kidney stone prevention programme at NYU, gave his advice for oxalates in the diet.
He advised that if you have experienced kidney stones before, to eat less of foods containing high levels of oxalate. However in most cases, you don’t need to remove it completely.
If you have not experienced kidney stones before, with or without a family history of kidney stones, you don’t need to worry about the oxalate content of your foods.
In every case, it’s important to stay hydrated and get enough calcium. This is because high fluid intake lowers the concentration of calcium, oxalate, uric acid, and phosphate in urine and is crucial in lowering the risk of kidney stones. Studies also show that higher calcium intake is associated with lower levels of kidney stones.
Sources
Bong, W-C. et al. (2017). Addition of calcium compounds to reduce soluble oxalate in a high oxalate food system. sciencedirect.com/science/article/abs/pii/S030881461631648X
Cleveland Clinic (2022). What’s the Difference Between Gallbladder and Kidney Stones? https://health.clevelandclinic.org/whats-the-difference-between-gallbladder-and-kidney-stones
Goldfarb, D. MD. Oxalates & Kidney stones. youtube.com/watch?v=qq1nkGqo69E
Kumar, P. et al. (2021). Dietary Oxalate Loading Impacts Monocyte Metabolism and Inflammatory Signaling in Humans. frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.617508/full
Lin, B.B. et al. (2020). Dietary and lifestyle factors for primary prevention of nephrolithiasis: a systematic review and meta-analysis. https://pubmed.ncbi.nlm.nih.gov/32652950/
Mitchell, T. et al. (2018). Dietary oxalate induces monocyte mitochondrial dysfunction and crystalluria in healthy subjects: A role of spinach in kidney stone disease? faseb.onlinelibrary.wiley.com/doi/10.1096/fasebj.31.1_supplement.1030.18
NIDDK (2017). Symptoms & Causes of Gallstones. https://www.niddk.nih.gov/health-information/digestive-diseases/gallstones/symptoms-causes
Petroski, W. & Minich, D.M. (2020). Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds. https://pubmed.ncbi.nlm.nih.gov/32987890/
Taylor, E.N. & Curhan, G.C. (2007). Oxalate intake and the risk for nephrolithiasis. https://pubmed.ncbi.nlm.nih.gov/17538185/
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