Check out this answer from Consensus:
The traditional view that the human body contains ten times more bacterial cells than human cells has been challenged by recent research, which suggests a near 1:1 ratio. However, some studies still support the 10:1 ratio, particularly in the context of the gut microbiome. Overall, the exact ratio may vary, but it is clear that the human microbiome plays a crucial role in health and disease.
The human microbiome, particularly the bacterial component, has been a subject of extensive research due to its significant role in health and disease. A commonly cited claim is that the human body contains ten times more bacterial cells than human cells. This analysis aims to synthesize findings from multiple research papers to address the accuracy of this claim.
Key Insights
- Revised Estimates of Bacteria to Human Cell Ratio:
- Recent studies have revised the widely cited 10:1 ratio, showing that the number of bacteria in the human body is actually of the same order as the number of human cells. The updated estimates suggest approximately 3.9×10^13 bacterial cells and 3.0×10^13 human cells, indicating a near 1:1 ratio2 10.
- Support for the 10:1 Ratio:
Do our bodies have 10-times more bacteria than human cells?
Hanne Tytgat has answered Unlikely
An expert from Wageningen University and Research Centre in Microbiology, Microbiome
The saying that we are outnumbered by a 10-fold of bacterial cells in the human body is based on an old estimation. Recently Sender et al. upgraded our humanness to 50%. This means that there is most probably a 1 to 1 correlation bacterial vs. human cells.
Link to paper of Sender
https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533
Link to interesting news article on Nature about this:
https://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136
Do our bodies have 10-times more bacteria than human cells?
Bruno Pot has answered Uncertain
An expert from Vrije Universiteit Brussel in Microbiology
The idea that we have 10 times more bacteria than human cells goes back to an original paper from 1972 by Thomas Luckey, which was never intended to be cited in the context it was used for decades. In 2016 the number was actually re-evaluated by Sender, R., Fuchs, S. & Milo, R (https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533) and reduced to 3.8·x 10 exp 13 bacteria (about 200 grams) in a 70 kg “reference man” , compared to 3.0 x·10 exp 13 human cells, indicating that the number of bacteria in and on the body is actually similar to the number of human cells. Some further reading: https://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136#graphic.
Do our bodies have 10-times more bacteria than human cells?
Chantelle Penney has answered Uncertain
An expert from Trent University in Biology, Ecophysiology, Marine Biology
I’m not entirely sure. But considering the number of bacteria that is maintained on our skin and in our digestive tract (mouth included), and that a bacterial cell is approximately just one tenth of the average size of an animal tissue cell, I would say that it could be possible for the amount of resident bacterial cells to outnumber the amount of the tissue cells that make up an adult human.
Do our bodies have 10-times more bacteria than human cells?
Hannah Wardill has answered Extremely Unlikely
An expert from University of Adelaide in Gastroenterology, Microbiome
This claim was made several years ago based on early estimates. It has now been revised, and the general consensus is about 3-1 (microbes to human cells), but may be more like 2-1 or even possibly 1-1. Nonetheless, we are essentially just as much bug as we are human which is still impressive in my books!