How much dirt do I consume annually?

While it's common knowledge that eating dirt is discouraged, it happens unintentionally every day. Dirt finds its way into our systems constantly, whether we like it or not. Pinpointing the exact amount ingested is challenging, but perhaps not the main concern. As a researcher studying dirt consumption aptly put it, "Apart from water, the majority of what constitutes our bodies is essentially dirt... Most solid components in humans and other organisms either currently are or were once dirt... transformed by sunlight into flora or fauna."

Our daily intake of dirt occurs through various means, such as contaminated food, inhaling dust, and neglecting to wash our hands before meals. The Environmental Protection Agency (EPA) has conducted extensive research on dirt ingestion. The dirt we consume is primarily divided into two categories: soil and dust. Roughly 45% of what we inhale or accidentally eat is soil, while the remaining 55% is dust.

The EPA data on accidental dirt ingestion highlights children, with research indicating that infants aged 6 weeks to 1 year typically consume 60 milligrams daily. For those between 1 and 20 years old, the intake rises to 100 milligrams per day. (To put this in perspective, 50 milligrams is equivalent to one-sixth of an aspirin tablet, so the amount of dirt ingested is relatively small). When calculated annually, this amounts to 36,500 milligrams or 1.3 ounces per year—a figure that isn't particularly alarming.

Children, as is widely known, have a particular fondness for eating dirt, especially between the ages of 1 and 3. One expert suggested that while this behavior stems from curiosity and the newfound ability to explore and interact with their environment, it might also be an attempt to obtain essential vitamins and minerals. Intentional dirt-eating often begins around the age of one, coinciding with the cessation of breastfeeding, possibly as a way to compensate for lost nutrients.

Some individuals continue consuming dirt beyond early childhood, a practice known as geophagy or soil pica (pica refers to the habit of eating non-food items). In American society, geophagy is viewed with both concern and intrigue. In fact, pica is officially recognized as a disorder by the U.S. Agency for Toxic Substances and Disease Registry, with intentional dirt consumption exceeding 500 milligrams daily classified as "pathological" [source: Callahan]. However, historically and in various cultures, eating dirt is not considered unusual. For instance, some pregnant women in sub-Saharan Africa consume dirt to alleviate morning sickness or to provide additional nutrients to the developing fetus [source: Callahan].

While concerns about contaminated food and soil are valid, perhaps unintentional dirt consumption isn't as worrisome as it seems. After all, it's a natural occurrence, and, in a way, we are all composed of dirt, aren't we?