Why Does Spinach Make My Teeth Feel Weird?

There is a lot to love about spinach. The versatile greens star in many of my favorite weeknight meals, dips, and breakfast smoothies. What I don’t love, though, is getting spinach teeth. No, I’m not referring to spinach stuck between your teeth—I’m talking about the chalky feeling that develops in your mouth and over your pearly whites after you’ve eaten the vegetable. For a long time, I thought I was the only one who experienced this funny sensation, but a quick internet search and a survey of my colleagues proved otherwise. What exactly is this peculiar feeling and why does it happen? Is there any way to prevent it? I rolled up my sleeves, did a little reading, and reached out to food scientist Harold McGee to find out.

Why do my teeth feel weird after eating spinach?

Spinach is full of oxalic acid, a compound that’s also found in leafy greens like Swiss chard, amaranth, beet greens, and sorrel. In his book The Flavor Equation, Nik Sharma notes that oxalic acid is also what makes these vegetables taste more acidic when raw.

As the spinach cooks, the cell walls break down and release oxalic acid that coats the mouth when you eat the vegetable. It’s as if your teeth have been lightly scratched against—an unpleasant feeling that lingers for an hour or two afterward. Over email, McGee, the author of On Food and Cooking, told me the sensations caused by oxalates in spinach haven’t been much studied. He notes: “There are both dissolved oxalates and hard spiky calcium oxalate crystals, and the latter are likely (though not proven) responsible for the fine grittiness we experience.”

Can you prevent spinach teeth?

In his book Tender: A Cook and His Vegetable Patch, British food writer Nigel Slater recommends “tossing your freshly cooked [spinach] leaves in melted butter or cream” to reduce the fuzzy mouthfeel. Cook’s Illustrated, however, found that eating and cooking spinach with dairy—which is rich in calcium—made spinach teeth worse.

I asked McGee if he knew of any way to lessen the feeling of spinach teeth—and if cooking or eating spinach with dairy would, indeed, solve the problem. McGee tells me, “The dissolved oxalates will react with calcium-rich foods like milk to form calcium oxalates, but that would just add to the grittiness.”

But that doesn’t mean you should retire your favorite recipe for creamed spinach. The combination of spinach and milk, McGee says, “is recommended more to keep dissolved oxalates from entering our bloodstream, where they can contribute to the development of kidney stones.”

So what’s a spinach lover to do?

There hasn’t been all that much research on how one can reduce the unsettling, scratchy effect the leafy green has on your teeth, but McGee suggests one work-around: “The best way to deal with the grittiness is to bury [the spinach] in ingredients with more pleasing textures.” He warns that “any treatment that would actually dissolve the crystals—such things as a lot of acid and/or long cooking—would also drastically change the spinach itself.”

If you’re desperate to avoid spinach teeth, your best bet might be to avoid the leafy green altogether. In the name of science, though, I conducted my own little experiment by preparing spinach in as many ways as I could think of. I blanched it, creamed it, blanched and creamed it, sautéed it, and whizzed it into my green smoothies. Though the experiment left me with more questions than answers, my favorite method was blanching and then creaming spinach—not because it didn’t leave me with spinach teeth, but because it was so delicious that it honestly didn’t matter that my teeth felt chalky after.

Creamed Spinach

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