Newsflash, fellow human being: More than half of your body is not human, according to a study reported by the BBC. No, seriously.
The shocking report has revealed that human cells make up only 43 percent of the body’s cell count. The question then is: What in the world is the other 57 percent?
The 57 percent. As it turns out, more than half of the human body is made up of microscopic colonists and not, well, human stuff. Now, we know what you’re probably wondering: What TF are microscopic colonists and how are they not human? Don’t worry, we’ll get to that in a bit.
Microbiome. The important thing to know about this is that understanding this hidden part of humans — the microbiome — is rapidly changing how scientists understand diseases like Parkinson’s. What’s more, the field is even asking questions of what it truly means to be “human,” the BBC reports.
The 57 percent. OK, so let’s get back to the 57 percent. Namely, what the hell is it? “The remaining 57 percent are bacteria, fungi and single-celled eukaryotes that live in our guts, in our mouths, on our skins, and in the female reproductive tract,” Sarkis Mazmanian, a microbiology researcher at Caltech, explained to the BBC.
The 57 percent. Mazmanian added: “Bacteria far outnumber fungi and other microbes, and most of these microbes are found in the gut, thus almost all of the 57 percent are intestinal bacteria.” In laymen’s terms? The 57 percent is all sh*t you’ve been told to steer clear of your entire life. Yes, seriously.
Essential. As icky as they may sound, these, um, things are important for your overall well-being. “They are essential to your health,” Professor Ruth Ley, the director of the department of microbiome science at the Max Planck Institute, told the BBC, “your body isn’t just you.”
Microscopic creatures. No matter how well you shower, your body is always covered in these microscopic creatures. “This includes bacteria, viruses, fungi, and archaea (organisms originally misclassified as bacteria),” the BBC explains. “The greatest concentration of this microscopic life is in the dark murky depths of our oxygen-deprived bowels.”
More microbe than human. Speaking to the outlet, Professor Rob Knight, from University of California San Diego, further noted: “You’re more microbe than you are human.” Initially, it was believed that there are 10 times more bacteria cells in any individual’s body than human cells.
Refined. “That’s been refined much closer to one-to-one, so the current estimate is you’re about 43% human if you’re counting up all the cells,” Knight went on to point out. That said, it hasn’t always been like this— meaning that even though you were born exclusively human, you became less human over the first few years of life as bacterial colonies took over.
Born without. “Most studies show that humans are born without microbiome colonization, and thus, we acquire our resident microbes first during the birthing process and then throughout early life,” Mazmanian explained to the BBC. “By the age of three, our microbiomes look ‘adult-like.’”
Dynamic change. Speaking to Mel Magazine, Cédric Feschotte, a biologist at the University of Texas at Arlington, revealed that he agreed with Mazmanian on the matter. “I’d imagine that during our lifespan, starting from an embryo, there’s a dynamic change in the number of microbes,” he explained.
Exact percentage. Still, Feschotte doesn’t necessarily agree with all of it— namely, what he doesn’t agree with is assigning an exact percentage. His argument? That “it’s too difficult to account for the myriad different types of microbial organisms that make up our bodies,” according to Mel Magazine.
Better understanding. However, Feschotte does believe that it’s important for scientists to continue to better understand how human cells interact with non-human cells. Why you say? Because by doing so, people will be better able to understand the way human bodies develop.
Increasingly evident. “It’s increasingly evident that there are intimate actions and behavior of cells between these microbial organisms and human cells,” Feschotte explained to Mel Magazine, adding that “this is why he believes there’s a growing appreciation for a holistic view of disease and how best to respond to an infection.”
Transform health. Speaking to the BBC, Knight echoed Feschotte’s sentiments. “We’re finding ways that these tiny creatures totally transform our health in ways we never imagined until recently,” he explained.
Human. So, what exactly makes you human if not your body? DNA, apparently— with a bit of some other stuff. “What makes us human is, in my opinion, the combination of our own DNA, plus the DNA of our gut microbes,” Mazmanian told the BBC. Sounds good enough.