Have you ever eaten a salad with fresh spinach leaves in it and found yourself with a weird, chalky feeling on your teeth? Don’t worry, you’re not alone. This is such a common phenomenon that it actually has its own name: Spinach teeth.
While many people may have eaten fresh spinach and not noticed any unusual effect on their teeth, some people find spinach teeth to be such an unpleasant feeling that they avoid fresh spinach altogether. But what causes spinach teeth, and are your teeth in danger from this weird feeling?
What Is “Spinach Teeth”?
Spinach is a unique food, hailed for its high nutritional value. This green leafy vegetable is packed with vitamins, minerals, fiber, and is an excellent source of iron. But there’s another thing it’s packed with — oxalic acid.
This naturally occurring chemical is present in plenty of plants, including beets, rhubarb, and strawberries. And while the other nutrients in spinach are considered beneficial, oxalic acid is what is known as an “antinutrient.” This is because they bond with other nutrients, preventing the body from absorbing them. In this case, oxalic acid bonds with calcium.
Your saliva contains calcium, so when you eat spinach, the oxalic acid in the leaves bonds with the calcium in your saliva, creating calcium oxalate crystals. Those miniscule crystals are not water soluble, so they just float around in your mouth, creating a strange, gritty feeling.
Is It Dangerous?
Eating spinach isn’t inherently dangerous. You have plenty of other sources of calcium, so you don’t have to worry about mineral bonding preventing the absorption of important nutrients. And while those crystals might make your teeth feel weird, they won’t harm your enamel and are perfectly safe for your teeth. In fact, it may even be helpful. Oxalate (part of the oxalic acid molecule) is commonly used to treat sensitive teeth. The belief is that calcium oxalate crystals form in the tiny tubules of the teeth that can contribute to sensitivity.
If the feeling of spinach teeth is unpleasant to you, you can brush your teeth after eating spinach, boil or steam your spinach, or even top your spinach with lemon juice (the ascorbic acid will help break down the oxalic acid, reducing the effects.)
However, if you have a tendency to form kidney stones, fresh spinach might not be a smart addition to your diet. Since those crystals aren’t water soluble, they contribute to increased oxalate in the urine. This means that for people who easily develop kidney stones, the calcium oxalate crystals formed when you eat raw spinach could contribute to kidney stone formation.
“Spinach teeth” might be common enough to warrant a name, but there are plenty of foods that can leave your teeth feeling grimy or gritty after eating. While brushing twice a day is enough to keep your teeth clean and prevent decay, there is certainly no harm in throwing in additional brushing sessions if you have eaten something that you feel is clinging to your teeth. Just make sure you’re using a soft-bristled toothbrush and brushing in a gentle, circular motion to avoid overbrushing and potentially damaging your enamel.