Your Brain Wants You to Eat Dirt

What’s fun about the title to this blog post is the very idea that your brain “wants” you to do anything. As if your brain had a separate will from “your” will. It smack of Karl Pilkingtonism, from which we get the utterly wonderful quote “is my brain in charge of me or am I in charge of my brain?” 

Actually, if you Google the phrase: “Who’s in charge, me or my brain?” You’ll get millions of hits, and links to familiar news and science sites. So it’s not a stupid question at all. But the very idea of you brain “wanting” something belies a belief that your brain “knows” what’s good for it—even if “you” don’t.

Ever have a craving for something odd? Could that be your body “knowing” that a key nutrient you lack is in that food you’re hungry for? Or is that your body remembers not lacking in some capacity the last time you at that food? Is this what we mean when we sat your brain wants you to eat dirt?

No, it’s not, this time. We’re not talking about pregnancy and geophagy, where women will sometimes crave eating dirt, either because their bodies are mineral deficient or they want to boost toxin immunity (scientists aren’t exactly sure). We’re not talking about pica, the psychology (and probably pathological) desire to eat non-food items. We’re just talking about mycobacterium vaccae.

It seems that ingesting this bacteria has been shown to have a positive effect on learning and memory. Mice who were given the bacterium showed increased levels of serotonin and were able to navigate mazes faster and with less anxiety. Further tests showed this to be a temporary effect.

However, before you go outside and start adding real ground to you coffee grounds, be aware that the tests cited were not performed on humans, and that there’s no guarantee the dirt in your front yard contain the bacterium at all. You’d be better of simply go for a vigorous hike in the a natural area, and simply breathe deep the loamy aromas of the wilderness.

And what’s great about using yourself in such an experiment is that even if you don’t inhale any mycobacterium vaccae, or not enough to do anything, you’ll still reap benefits from the hike itself.

While it’s “fun” to say your brains wants you to eat dirt, we can promise your brain really does want you to exercise and immerse yourself in tranquility. So go for the hike and let us know how it makes you fell.