Although the idea of eating clay as a “delicacy” may seem foreign, most of us are already dirt eaters in our daily lives in that we seek salt from the earth or oceans to add to our diet. We usually don’t think of salt as dirt, but salt is a deposit found in rocks, and clay and dirt are nothing more than weathered rocks.

We take for granted that our use of the saltshaker is an almost universal form of geophagy (The practice of eating dirt is called geophagy. This is the scientific term for consuming the earth.

We don’t even see this as a form of dirt eating when we ask our partner to “pass the salt.” Think about that the next time you’re deciding between purchasing that fancy bottle of pink Himalayan salt or the venerable bottle of sea salt.

Because salt is scarce in many parts of the world, animals also practice geophagy and must seek out salt licks or salt mines to supplement their diet. Carnivorous animals really don’t need to add salt to their diet because the muscles and guts of their prey have enough sodium to meet their needs. But most herbivores and omnivores—and that includes humans— cannot rely on natural foods alone for adequate amounts of the nutrient, essential to nerve transmission, muscle contraction, and the maintenance of fluid balance.

Humans need around forty or fifty different nutrients to stay healthy so sometimes we have to go outside the bounds of what’s considered “food” and add these items to our diet.16

With regard to mineral ingestion from dirt, clay, or soil, we are supplementing our diets on a daily basis through other sources, too. When you eat an apple that hasn’t been fully washed, then there’s probably dust on it. On your vegetables like romaine lettuce, radishes, and potatoes, it’s the same thing.

This also goes for those peanut shells that you might like to suck on at the ballpark because they just taste plain good and even salty!

High doses of calcium added to milk and orange juice can be viewed as acceptable forms of geophagy as well. Calcite is a mineral that is the main constituent of limestone and can be purchased in single ingredient supplement bottles found in the health section of your local grocery store. But it is also found in such widely recognized health products as Rolaids and Tums, which are used to relieve indigestion and acid reflux. It’s surprising to learn that many of the foods we consume on a daily basis already fall into the category of geophagic eating.

As you can see, geophagy isn’t some strange, incomprehensible practice. We are all practitioners of geophagy nearly every day. And in some cases, that practice is essential to our health.