1% of the cells in your body are human?

The other 99% are bacterial? Really? Could this be? “I better google this,” you might be thinking to yourself.

Google away. The answer often tossed around, the one you will find in googling, is 90%. In other words, nine out of ten of the individual cells on your body are bacteria cells, or at least microbial cells. The 90% in this estimate include bacteria, archaea and the odd fungal species living in you. These cells are smaller than human cells and so their total mass isn’t as large as our total mass, but still large enough (picture something about the size of a small dog). OK, so the answer is 90%, not 99%. Well, sort of.

The estimate that 90% of our cells are microbial is based solely on the number of bacteria in our guts. The truth is bacteria also thrive in our hair, all over our skin and everywhere else on us and in us. Find a divot, dimple or crevice and they are filling it with their bounty and diversity (we have found nearly 4000 species of bacteria in bellybuttons alone). Could these bacteria get us up to 99% bacterial? Maybe. No one has really done a good tally. If you would like to do so, go ahead and afterward post the answer here.

The other thing one needs to take into account is the composition of our actual “human” cells. Even those cells are only partially human. They represent the fusion of multiple separate single-celled lineages, a chocolate and peanut butter like coming together to which we owe our existence. Once upon a time, no cells had mitochondria, those cellular powerhouses burning the midnight oil in your brain right now. Then, on some dark and stormy night, one single-celled organism engulfed another and in doing so took advantage of the powers of the smaller cell, powers that included the ability to respire. The descendants of these cells, their persistent genes, are allowing your brain to function right now, even as you wonder if this could all possibly be true.

So does all of this get us up to 99%? I don’t know. It gets us close and the math is fuzzy. But the point is clear enough, we are far more microbial than not and so while our conscious brains seem content to say, “scrub away the germs,” the germs are, well, the neglected masses who we need to thank for the activity in our brain, the first line of defense on our skin, the smell of our arm pits (OK, maybe no thank you necessary there) and the digestion in our guts. So scrub, scrub, scrub, if you choose, but know that if you were to really accomplish your goal of getting rid of all the “germs,” that what would be left would be something less, nothing but the one percent or so, give or take a billion, tiny cells.

 

By | 2016-11-22T13:47:43+00:00 January 24th, 2012|

About the Author:

Leave A Comment