Ingredient Intelligence

Why Does Spinach Leave a Weird Film on Your Teeth?

Christine Gallary
Christine GallarySenior Recipe Editor at The Kitchn
After graduating from Le Cordon Bleu in Paris, I worked at Cook's Illustrated and CHOW's test kitchens. I've edited and tested recipes for more than 15 years, including developing recipes for the James Beard-award winning Mister Jiu's in Chinatown cookbook. My favorite taste testers are my husband, Hayden, and daughter, Sophie.
published Sep 28, 2015
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Spinach Salad with Warm Brown Butter Dressing (Image credit: Sarah E Crowder)

I’m a spinach fan and love that it cooks quickly so I can stir it into eggs, pasta, stews, soups, or just about anything I choose. What I don’t love, however, is that strange film it leaves on my teeth. You know what I’m talking about — that unpleasant coating that’s both dry and chalky.

“Spinach teeth” is such a weird phenomenon; where does it come from, and is there anything that can be done to minimize or prevent it?

Where Does “Spinach Teeth” Come From?

Spinach is high in calcium and the insoluble form of oxalic acid, which forms crystals that stick onto your teeth as you chew on it. These crystals give that gritty, tannic feeling in your mouth and also give what some people characterize as a bitter taste to spinach.

While spinach is high in iron, vitamin A, and vitamin C, the high amount of oxalic acid also inhibits the body’s absorption of calcium and iron at the same time.

Creamy Spinach Bake (Image credit: Nealey Dozier)

Can You Counteract That Film?

There are lots of theories out there about how to reduce or remove the oxalic acid, with some of them going against each other; there’s not really a consensus on what actually works. Some say to avoid milk with spinach since it may introduce even more calcium to help form the crystals. Others say to cook or blanch the spinach, while some say to not cook the spinach at all and just eat it raw. Another theory is to add lemon juice or acid.

I personally notice the film more when eating spinach by itself rather than when it’s mixed into something else, but it’s probably because there’s a much higher concentration of spinach in each bite.

Do you have ways you treat spinach to avoid that gritty feeling?

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greens
Ingredient
Vegetables