Are we human? Or are we microbe?

Microbes. EEK!!!

We spend a lot of time and money on antibacterial products. But despite our desperate scrubbing, we will never be free of microbes.

In fact, our bodies’ microbial cells outnumber our human cells 10 to one! Which makes you wonder: If you have more microbial cells than human cells, are you human?

Of course! Humans play host to microscopic microbes, collectively known as the gut microbiome, that reside in the small and large intestine.

These microbial symbionts perform vital functions, especially during digestion.

Many of these genes encode enzymes that digest food, such as CAZymes, which break carbohydrates into compounds that the body can absorb or excrete.

If the composition of the gut microbiome changes, the body may lose the ability to perform certain functions, which could result in inflammatory bowel disease (IBD).

Even from the deep regions of our intestines, our gut occupants can influence much more than our bowel health.

Studies report colonization of certain species of bacteria is more likely to be associated with depression and anxiety. Many researchers believe adjusting the composition of the gut microbiome may be a viable treatment for these disorders.

We may be human, but we are run by microbes, no matter how many times we wash our hands.

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Check our facts!

1. Belkaid, Y. and T.W. Hand, Role of the microbiota in immunity and inflammation. Cell, 2014. 157(1): p. 121-41.
2. Cecchini, D.A., et al., Functional metagenomics reveals novel pathways of prebiotic breakdown by human gut bacteria. PLoS One, 2013. 8(9): p. e72766.
3. Forsythe, P., et al., Mood and gut feelings. Brain Behav Immun, 2010. 24(1): p. 9-16.
4. Costello, E.K., et al., Bacterial community variation in human body habitats across space and time. Science, 2009. 326(5960): p. 1694-7.
5. Cryan, J.F. and S.M. O’Mahony, The microbiome-gut-brain axis: from bowel to behavior. Neurogastroenterol Motil, 2011. 23(3): p. 187-92.

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Text by Kathryn Pietrosimone, Ph.D.

Kathryn Pietrosimone, Ph.D. is an immunologist that has been known to dabble in microbiology. Currently, she researches autoimmune diseases at UNC-Chapel Hill. Kathryn believes scientific research is most powerful when it is shared with others and therefore aims to explain and share science with all people, or at least those who follow her on Twitter (@kpietro). Contact Kathryn at Kathryn.pietrosimone@gmail.com.

Illustrated by Christin Hardy, Buzz Hoot Roar Artist in Residence.

Christin Hardy grew up in a teeny, tiny place called Seven Springs, North Carolina, where livestock outnumber people. Her father is a farmer and her mother is an artist, so naturally Christin turned out to be an artist who loves nature, infusing it into her work and life. Currently she works for the NCDOT designing posters, banners and brochures, but her heart lies in explaining science through illustrations and graphic design. You can find her on Instagram @c_creature, on Twitter @c_hristin or send her an email at c.creature.881@gmail.com.