Written by Raymond Nakamura
Once upon a time, Raymond earned his doctorate studying the hydrodynamics of sand dollars. Nowadays, when he’s not employed as personal assistant to his lovely and demanding daughter, he enjoys creating fun and educational experiences in science and history using facts and fiction, words, pictures and whatever else is handy. Follow him on Twitter @raymondsbrain

Why does spinach make my teeth feel funny?

I'm not much of a cook nor a particularly mindful eater, but the funny feeling I get from spinach has given me some food for thought. Do you know what I'm talking about? Not the grit left behind if you don't wash the leaves properly. Some have described the effect as chalky or  fuzzy

Turning Over a New Leaf

The most common answer seems to be  oxalic acid, also known as ethanedioic acid, which spinach has lots of. Other fruits and vegetables have to a lesser degree.  Rhubarb leaves, however, have so much  oxalic acid they are considered  poisonous. It may have evolved as a way for plants to discourage animals from eating it. 

Crystal Clear?

dentist said the residual feeling was from the oxalic acid combining with the  calcium in your saliva, to form crystals of calcium oxalate. But spinach is already has lots of  calcium oxalate in the leaves and saliva doesn't seem to have much. I haven't come across any direct experimental evidence to explain the feeling, so I looked for some more corroborating information.

Your Mileage May Vary

The funny teeth syndrome seems to be more associated with  cooked spinach than  raw, supported by my own anecdotal Facebook survey. Cooking breaks down cell walls so perhaps more oxalic acid or calcium oxalate gets out into your mouth as compared to eating fresh. Also the volume shrinks with cooking, so you would get more spinach mass in a given mouthful. 

Get Into the Kitchen

But cooking may  break down oxalic acid. I wonder if calcium oxalate is more stable or even gets formed by cooking. Cooking spinach makes it  more nutritious in some ways than eating it raw. I am no dietician, and I'm not going to get into the  real and  imagined nutritional benefits of eating spinach advocated by Popeye and others. Cooking with calcium-rich foods may also reduce the spinach effect. If anyone has any recipes that tend to reduce the spinach effect on a consistent basis, it might be interesting to see if has chemical components that alters the spinach tooth effect.

Testing, Testing

When I tried to test the spinach effect on myself, the difference between cooked and uncooked was minor. But as I said, I'm not much of a cook nor an especially subtle taster. As well, the amount of oxalic acid can differ by  variety of spinach, the age of the spinach, season, and  growing conditions. The tip of my tongue is now hurting, though I don't know if eating spinach was necessarily the cause of it. I'll let someone else test that idea on themselves.

So I'm still chewing on this one. I can't decide which explanation to swallow. But at least the next time I discover spinach in my teeth at a job interview, I'll have an excuse — I'm studying the dental effects of oxalic acid and calcium oxalate.

Comments

Hi Raymond! I have always

Hi Raymond! I have always experienced the very same thing, my suspicions were that it was the oxalic acid, as I couldnt really think of another food we eat that contains it and as the only other time I get a similar feeling is after eating lemon! Which of course contains another acid, It always felt to me like a thin coat of enamel was getting stripped off my teeth! I decided to just look this up after having spinach for my lunch! :)

I too liken the feeling

I too liken the feeling enamel being stripped off my teeth. As a side note I just ate a spinach salad and paired it with a tasty beer. The feeling on my teeth quickly diminished there after. Perhaps an interaction between the alcohol and acid?

Last night I ate a meal of

Last night I ate a meal of gnocchi with stracchino cheese sauce and a portion of cooked spinach, washed down with a couple of glasses of wine. The 'furry' effect was so bad that it prompted me to look it up on Google! So there's the calcium and alcohol theories down the drain as far as I go! As I was eating it and experiencing this effect I was wondering if it was the saponins in spinach. My tongue still feels odd this morning!

I have to agree that cooked

I have to agree that cooked is worse than raw and the cream sauces are worst of all. I figured that whatever chemical was responsible, the breakdown of cell walls during cooking made it worse. If calcium has anything to do with it then maybe cream could make it worse? Makes sense to me...

I get the furry feeling from

I get the furry feeling from lots of produce: underripe persimmons and bananas, raw and cooked spinach, even certain baked goods do it to me. I think the baked goods have to do with the baking soda. Would love more info about it as no one else in my family experiences this.

I have a feeling this may be

I have a feeling this may be to do with how acidic your own mouth is. I know I have a highly acidic gut and consequently saliva (tested with Ph paper on various occasions!) so perhaps it is this in combination with a high-alkali food like spinach which causes the effect?

Does anyone get this furry

Does anyone get this furry dry mouth feeling from green powder? I've had it for several weeks and am wondering if its the green powder Kyo green that I've been taking?

I just ate a salad with raw

I just ate a salad with raw spinach, and I am now expirencing this effect. A few days ago I ate cooked spinach and that chalky feeling appeared. I wonder if the food that you have with it affects the outcome. I have had spinach in my salad several times before without this outcome. I always drench my salad in Ranch, but this time I went without. And when I have had cooked spinach with alfredo sauce this feeling was absent.

Just had cooked spinach and

Just had cooked spinach and the feeling is horrible. I agree about it feeling like the enamel is stripped. Anyone found the ultimate companion food to neutralise this effect?

Is it funny teeth or funny

Is it funny teeth or funny tongue syndrome? Either something in the food is bonding to the enamel causing a particular roughened surface, or changing the receptors on the tongue. Experiment: lick other stuff when undergoing this effect. Or get someone else to lick your teeth to test their (the teeth) roughness.

I just cooked half a bag of

I just cooked half a bag of spinach with tomatoes in EVOO, scattered some egg whites, and lightly sprinkled with Italian cheese mix. My teeth felt very funny, sonic mentioned to my fiancée, and he had no idea what I was talking about, so I got home to lick my teeth... it is definitely something on the teeth because he felt it too, and he didn't eat what I ate. After I vigorously brunched my teeth I got him to lick my teeth again, and he said there was a definite difference! This is what prompted me to search for the answer!

I tend to grow lots of plaque

I tend to grow lots of plaque on my lower teeth which my dentist said is due to pH of my saliva. The way my teeth feel after eating spinach, raw or cooked, is similar but on all my teeth. Other's comments suggest that adjusting the pH may help clear the fuzz.

Thought you guys would like

Thought you guys would like to see this from: http://en.wikipedia.org/wiki/Oxalate The "gritty mouth" feeling one experiences when drinking milk with a rhubarb dessert is caused by precipitation of calcium, abstracted from the casein in dairy products, as calcium oxalate.

I also googled in the midst

I also googled in the midst of experiencing awful chalky spinach mouth. My spinach was steamed and eaten w garlic salt and lemon juice for flavor. No alcohol or dairy. Absolutely awful... until I followed up with a piece of Australian strawberry licorice and now my mouth feels perfectly normal, if due for a brushing. Maybe the higher sugar content form Bruce's beer vs Michael's wine made the difference in neutralizing the effect regarding alcohols?? And mad props to Bev and her fiancee! "Lick my teeth, for SCIENCE!"

I experience it as stripped

I experience it as stripped enamel also. Today was worse than usual prompting me to "google" it. Oddly I am dieting so I made a big spinach salad dressed with a low fat dressing that I created using fat free greek yogurt. I think this supports the calcium/oxalic acid interaction. Isn't the internet amazing.

My god, I just came across

My god, I just came across this page having just eaten an unripe persimmon and I felt like Jim Cary in me myself and Irene! Totally know where katfluff above is coming from. My whole mouth was stuck together! Think the issue here is lots of starch that is yet to be converted to sugar by ethylene.

Hi, great thread! I don't get

Hi, great thread! I don't get this mouth feeling from spinach hardly at all, but an extremly chalky tounge from sharon fruit (persimon?). Read on a webpage that the sharon effect disappears if you put it in the freezer for a while before eating it. Anyway, I now googled 'rhubarb mouth feeling', because last night my Mom and I had a rhubarb dessert that I'd made. After the dessert I said, 'the mouth feels pretty funny, doesn't it?' 'No, not mine' was my Mom's answer and we had had the same dessert! We've made this dessert since I was a kid and my mouth always went funny, but obviously not everybody else's!

Just had pasta with rose

Just had pasta with rose sauce(tomato/CREAM) tossed with a huge bunch of spinach and my i'm sitting here with my dental floss and toothbrush because this time my teeth feel like they're wearing felt sweaters! And my boyfrlend doesn' t even know what I'm referring to! I thought everyone experienced this but apparently not!

I Googled this after having

I Googled this after having wilted (not fully cooked) spinach in this recipe: http://www.marthastewart.com/312671/warm-spinach-salad-with-fried-egg-and-po?czone=food%2Fvegetarian-cnt%2Fvegetarian-favorite-recipes&gallery=360580&slide=312671&center=852566 There was one difference between the recipe and my preparation, which is that I used Gruyere cheese instead of Parmesan. I always experience this effect with spinach, as far as I can remember. I don't use cooked spinach much, so it's usually with fresh spinach. I'd describe it as my teeth--molars especially, since my front teeth don't really come into contact with the spinach--feeling sharper or rougher, and this time even parts of the roof of my mouth felt rough and dry. The hypothesis that something is being deposited there seems to fit my experience. My teeth seem fine when it wears off. Hopefully this data helps!

For me, the feeling is almost

For me, the feeling is almost isolated to my front teeth rubbing together. After reading this it definitely seems to be worse with dairy products and spinach together. I drank some beer, which didn't have a noticable effect, but then a tiny spoonful of sugar - that made a noticeable difference. Not completely gone, but no more goosebumps. I imagine something like soft candy would stick around long enough to really help... Next time!

Only two foods have this

Only two foods have this unpleasant effect on my teeth: spinach and rhubarb. I rarely eat spinach raw as I just don't like it that way, so I'm not sure about the furriness being worse with the cooked stuff, though I suspect it is. Rhubarb has exactly the same effect, which is a shame, since there's nothing tastier than a rhubarb pie. But I have to clean my teeth immediately after eating it because I can't stand the sensation and eating something else doesn't remove it. Have just eaten a nice oily chicken broth with fully cooked spinach in it, and sure enough I've got the furries.

I get this sensation after

I get this sensation after eating raw spinich in a salad. I have not experienced with with cooked. Yesterday it was the worst that it has ever been! I felt like the entire inside of my mouth was stuck to my teeth. I felt so dry I couldnt talk and had to brush my teeth twice! I dont eat cheese or creamy dressing-oil and vinegar only-But I did have chicken salad along with my spinich salad. Maybe the mayonaise made it worse?

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