Hello again, apteryx! What an interesting (if somewhat
It appears that the average human bacterial load is approximately 2 to
9 pounds, depending upon which reference source is consulted. Below
you'll find a variety of sources from which to choose.
"Within every human being is a flourishing, living colony of
approximately four pounds of bacteria. Most of these bacteria reside
in the human digestive tract although some are found elsewhere (i.e.
the oral cavity, throat, etc.)"
"There are between 2-4 pounds of bacteria in one's intestinal tract.
Scientists estimate that there are more bacterial cells in your
gastrointestinal tract than the entire number of cells in the rest of
your body. There are two types of bacteria in our intestinal tracts:
there is beneficial bacteria and pathogenic or harmful bacteria. The
ratio of beneficial to harmful bacteria is perhaps the most crucial
element in our health today. Researchers estimate that the average
intestinal tract of a healthy individual should be approximately 85%
beneficial and 15% pathogenic. While that 15% pathogenic is still in
your body, it is benign when it is in the presence of the 85%
beneficial bacteria. The real problem here is that the average
individual, consuming the standard American diet, has the exact
opposite ratio, which is 15% beneficial and 85% pathogenic."
"A normal human being hosts about 1.2 kilograms of bacteria (8). The
bulk are in the gut lumen, and the rest in the skin, oro-pharynx, and
"Bacteria are all around us even though we cannot see any of them.
They affect our everyday life, and in fact we could not live without
them. Bacteria perform necessary functions for humans; the most
important is the breakdown of food in our intestines. The average
human actually has around 1.2 kilograms of bacteria in their body."
"A normal human being hosts about 1.2 kilograms of bacteria. The bulk
are in the gut lumen, and the rest in the skin, oro-pharynx, and
genitalia. Some are potential killers and yet they thrive without
La Tribune de la Gauche Républicaine
There are other estimates on the Web ranging from 2 to 9 pounds. Here
are two of the larger estimates:
"At any time we carry about seven pounds of bacteria, all busily
Dewan Kraft Systems
"The average human female carries nine pounds of bacteria on her skin
or within her intestines."
Flashed MRG Radio
Obviously, the amount and weight of a human's microbial contents will
vary, depending upon the size of the human and the sort of diet that
has been consumed.
You may be interested in an answer given by my friend and colleague
tehuti-ga to a similar question:
Google Answers: Microorganisms intake
Finding the proper search terms to unearth this information was a
challenge. These were the combinations of keywords that gave me the
Google Web Search: "pounds of bacteria" + "human"
Google Web Search: "kilograms of bacteria" + "human"
Thanks for providing a fascinating quest. If any clarification is
needed, please ask.