Are oxalates bad for you: A look at the data

Many people take to low-oxalate diets to improve mysterious health issues without considering if oxalates are bad for you. They read on the internet that they are, so why dig into it any further?

The problem is, the answer isn’t exactly straightforward. Calcium and oxalate form stones in the kidneys, and are the most common stone-type found in stone-formers.

But, this in and of itself doesn’t necessarily mean that oxalate is bad. In these individuals, restricting high-oxalate foods may be helpful. However, other dietary strategies reduce the oxalate burden further. Consequently, high oxalate foods are highly nutritious.

A new paper found that high oxalate intake increased cardiovascular disease risk in healthy people. To the untrained eye, this means we should avoid oxalates in our diet.

The problem is, there was a big fat caveat that shows us why this data came about. It also shows us why oxalate in the diet isn’t the boogie man many people make it out to be.

A high consumption of oxalates in the diet increases CVD risk, but…

One of the problems with focusing simply on oxalate intake and health outcomes is how we make deal with oxalate. In addition to oxalate contained in foods, we also make oxalate from the amino acid hydroxyproline and ascorbic acid.

On top of this, we also make oxalate as a byproduct of metabolism from glyoxylate. You don’t really need to know the specifics, just know that we make it in the liver and type 2 diabetics make a ton of it.

This new paper tells us a completely different tale, and involves how we absorb oxalate. In this paper, a high oxalate diet substantially increased CVD risk(>200%) substantially compared to a low oxalate diet. The problem is, the risk completely lost significance in people with medium to high calcium intake.

Why calcium? In addition to combining with calcium in the kidney, oxalate combines with calcium in the gut. And when bound to calcium, you simply don’t absorb dietary oxalate. So how much calcium, did one need to eliminate the significance? Around 50% of the daily requirement, or 545mg.

In other words, calcium deficiency is the problem, not a problem with oxalates. But this isn’t surprising.

Way back in 2009, a study compared a low oxalate diet to a diet low in animal protein and salt, and high in calcium in people with mildly elevated urinary oxalate. The low animal protein/salt/high calcium diet outperformed the low oxalate diet in lowering urinary oxalate.

It actually blew it out of the water, a 29.2% drop in urinary oxalate compared to a 12.7% drop in the low oxalate diet. On top of that, the average calcium intake of participants prior to the study was 588mg, which is in that deficient range.

Why animal protein? It’s a rich source of hydroxyproline. Why low sodium? It increases calcium in the urine, which can bind with calcium in the kidneys and cause calcium oxalate stones.


On paper, it makes sense for people with oxalate problems to consume a low oxalate diet. The problem is, the oxalate we are exposed to is dictated by much more than dietary oxalate.

Our body is exquisitely capable of dealing with dietary oxalates. Furthermore, we make more oxalate in our body than we consume. When we lack other components of a healthy diet or have issues such as type 2 diabetes or leaky gut, these mechanisms fail.

And the worst part is, the best way to maintain these mechanisms and our tolerance to oxalate is to maintain a diet that contains oxalate. We covered this previously in a blog you can check out here.

But this brings us to what should we do if we have issues with oxalates? In our next video blog, we take a deeeeeeeep dive into oxalate. We’ll cover how we make it, how we deal with it, and how other parts of our diet dictate our ability to keep oxalate in check.

You won’t want to miss this one!

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