My beautiful picture

OUR BOYS ARE now 20, 18 and 16 years old. My wife and I sometimes look back over those years and cringe at some of the things that have ended up in the boys’ mouths or that they’ve investigated with their tongues.

My wife and I lived in New York for a time, and I remember attending a church service with her and one of our sons, who then was 2 or 3. We were in a long line of people going up some stairs when I looked down to see that our son was not only holding onto the handrail as we often instructed him; he was running his tongue along it as well.

I generally don’t get too excited about these types of things; I guess I’ve learned to focus more on the entertainment value they provide. As he continued to climb the stairs, running his tongue along the railing, I nudged my wife, who hadn’t yet noticed what our little lickster was doing.

As I imagined she would, my wife reacted with horror and disgust that her sweet little boy, dressed in his Sunday best, had just tasted nearly the entire length of a handrail that was grasped by hundreds of fellow churchgoers that morning. You can guess how that made for even more entertainment!

Whether it’s eating dirt, putting grimy toys or fingers into mouths, or licking things that probably shouldn’t have contact with a tongue, a growing body of evidence shows that exposure to germs and bacteria in childhood leads to stronger immune systems in adolescence and adulthood. That will be the topic of a future chapter.

Getting back to eating dirt, I would like to draw a distinction between normal childhood mouthing practices and what falls into the category of disordered eating.

Normal mouthing practices can include children putting dirty toys or other objects in their mouths, sucking on filthy fingers, or even grabbing a handful of dirt or sand and taking a bite just to see what it tastes like—incidents many parents have observed.

Pica is a disorder of eating non-food material that could include coffee grounds, cigarette butts, tissues, paper towels, chalk, paint, laundry detergent and lots of other things. Geophagy is a pica disorder specific to eating soil or dirt.

People who study geophagy hypothesize that there could be two reasons for someone to have the urge to eat soil or dirt:

1. A desire to consume minerals found in dirt—calcium, for example—might especially apply to populations in emerging countries where mineral deficiencies are more prevalent.

2. There could be a detoxifying effect from eating dirt. It is possible that negatively charged ions in dirt could bind to positively charged ions in toxins, thus preventing their absorption. Scientists continue to investigate this possibility.

Most kids who eat a bit of dirt or put things in their mouths do so out of curiosity and not because they have geophagy; however, if you suspect that your child has a bit of an obsession with eating dirt or soil, you might want to share that with your pediatrician.

As you can imagine, trying to measure how much dirt a child eats in a year would be challenging. Ramon Barnes took on that challenge in his article “Childhood soil ingestion: How much dirt do kids eat,” which is published in the journal Analytic Chemistry.

Barnes describes how, after considering a number of ways to try to measure soil ingestion, he settled on a method of following consistent sample meal and snack patterns for a period of weeks and measuring excreta (feces and urine). He learned that the average soil ingestion was about 26 mg a day, which is 9,490 mg a year, which equates to roughly one-third of an ounce.

So based on the available evidence, which is somewhat limited (more studies need to be conducted), I would have to conclude that kids do not eat a pound of dirt a year. On the contrary, it is actually less than an ounce.

Barnes., R: Childhood soil ingestion: How much dirt do kids eat? Analytical Chemistry (1990), Vol 62, pp. 1023-1033.