Skip to Main Content

5 weird facts about the gut microbiome

Gut microbiome health

5 weird facts about the gut microbiome

You might be very, very surprised.

The gut microbiome contains more than friendly bacteria — it’s also rich with fun facts. Here are 5 of our favorite facts about the microbiome you may not have known. Digest it on your own or save it to enliven your next cocktail chat. 


1. There are at least as many bacterial cells in the gut microbiome as there are human cells in your entire body.

It’s hard to see ourselves as something more than human, but, research indicates we’re as much human as we are bacteria (at least when it comes to the number of cells in our body). It’s hard to know exactly how many bacterial cells are present in the average person’s gut microbiome, though recent estimates suggest the number is close to 10 trillion, which is equivalent to the number of human cells. And that’s not even counting the bacteria that live on our skin and elsewhere.


2. The gut microbiome contains more than bacteria.

A good look at the diversity of life in your gut reveals representatives from every domain of life. This includes fungi (eukaryotes), bacteria (prokaryotes), and even methanogens, microorganisms known for inhabiting some of the most hostile environments on earth (archaea). Scientists have yet to characterize every organism present in the human microbiome, but it’s clear that each of us hosts an ecosystem that’s alive with various forms of life. 


3. Ancient medicine involved fecal transplants.

The concept of engineering a healthy gut microbiome has a long history in human medicine. The first record of a gut microbiome transplantation dates back to the 4th century, wherein golden soup (also known as yellow soup) was used as a cure for food poisoning and diarrhea. The soup, developed and prescribed in China, used fecal matter as a primary ingredient. Though they didn’t know the specifics of how it worked, the developers understood that diarrhea and food poisoning could signal an imbalance within the body and that this soup may help to restore it. We know now that fecal transplants can cause a shift in the microbiome and, when done right, result in a healthier microbiome. (Don’t worry, we won’t share the recipe.)


4. Your gut instincts may be more than a phrase.

Mounting evidence suggests that a person’s mood, diet, behavior, and susceptibility to diseases — such as Alzheimer’s disease — may be influenced by their gut microbiome. Findings like these have prompted some scientists to refer to the gut microbiome and its relationship with the enteric nervous system, the network of nerves found in your stomach, as a second brain. Because most of this evidence comes from studies done with mice, it’s still too early to say definitively how or to what extent bacteria affect human behaviors, but the evidence so far suggests your gut instincts may be more than just a phrase.


5. Over your lifetime, your microbiome evolves.

 Your gut microbiome matures and gathers a healthy diversity of bacterial species over time. However, old age is also known to usher in a decline in gut microbial diversity. Such a decrease is thought to contribute to various illnesses that are common in older age. Researchers are hopeful that ongoing studies will help reveal which species of bacteria are beneficial for human health, ultimately leading to microbiome-focused therapies to help to protect us from illness.


After a long and storied history, and now with an increasing amount of research, scientists are learning how to work with the gut microbiome to improve human health. Pendulum’s Glucose Control is among the most recent innovations produced by this upsurge in research. Learn more about Pendulum Glucose Control and how it can help to manage type 2 diabetes



  • Sender, Ron et al. “Revised Estimates for the Number of Human and Bacteria Cells in the Body.” PLoS biology vol. 14,8 e1002533. 19 Aug. 2016, doi:10.1371/journal.pbio.1002533
  • Thursby, Elizabeth, and Nathalie Juge. “Introduction to the human gut microbiota.” The Biochemical journal vol. 474,11 1823-1836. 16 May. 2017, doi:10.1042/BCJ20160510
  • Gaci, Nadia et al. “Archaea and the human gut: new beginning of an old story.” World journal of gastroenterology vol. 20,43 (2014): 16062-78. doi:10.3748/wjg.v20.i43.16062
  • Laforest-Lapointe, Isabelle, and Marie-Claire Arrieta. “Microbial Eukaryotes: a Missing Link in Gut Microbiome Studies.” mSystems vol. 3,2 e00201-17. 13 Mar. 2018, doi:10.1128/mSystems.00201-17
  • Mukhopadhya, Indrani et al. “The gut virome: the 'missing link' between gut bacteria and host immunity?.” Therapeutic advances in gastroenterology vol. 12 1756284819836620. 25 Mar. 2019, doi:10.1177/1756284819836620
  • de Groot, P F et al. “Fecal microbiota transplantation in metabolic syndrome: History, present and future.” Gut microbes vol. 8,3 (2017): 253-267. doi:10.1080/19490976.2017.1293224
  • Vijay-Kumar, Matam et al. “Metabolic syndrome and altered gut microbiota in mice lacking Toll-like receptor 5.” Science (New York, N.Y.) vol. 328,5975 (2010): 228-31. doi:10.1126/science.1179721
  • Sgritta, Martina, et al. “Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder.” Neuron, vol. 101, no. 2, 2019, doi:10.1016/j.neuron.2018.11.018.
  • Xu, Congmin et al. “Aging progression of human gut microbiota.” BMC microbiology vol. 19,1 236. 28 Oct. 2019, doi:10.1186/s12866-019-1616-2