If you ever have the urge to chew ice you may have an iron deficiency. If this is the case you’re lucky – other mineral deficiencies create far more bizarre urges.
Mineral deficiencies often create uncontrollable urges to eat dirt, wood, drywall, chalk, styrofoam, clay, and many other materials.
Pica is the adorable name for this condition.
People who experience it cannot explain it. They know how ridiculous it is, but the biological urge is uncontrollable, like a reflex. Biologically this is an adaptive behavior. These flavorless and nutritionally empty objects contain loads of minerals.
We like to think that as humans we are in ultimate control of our actions, but how do you decide what to do for the day, what to eat, or what movies you like? We control our actions, but the desires that compel us to action, the motivations that lead to our actions and behaviors, like and dislikes, are completely unconscious.
One day I may have the urge to go golfing, and I may choose to give in, but where did that urge originate?
We may control thoughts once they’re in our head, but where do they pop up from to begin with? Our actions and behaviors are dependent on whether our brain tells us something will feel good or bad. We control the action itself, but not the underlying desire.
If I choose to buy a new shirt I may choose the action, but I have no control over what led my brain to desire that shirt in the first place.
Likewise, when these mineral deficient individuals reach for a lump of clay to chew on they voluntarily choose that action, but are compelled by an underlying desire that says “You will enjoy this, so do it! Do it now!”.
This is a relatively new field of study, but there is growing consensus that mineral deficiencies are a contributing factor to the development of many behavioral disorders like autism. Toxic substances like lead, cadmium, and mercury can displace mineral distribution and then cause pica, and eventually permanent behavioral disorders.
I Have an Interesting fact Fetish, and I Can't Stop 