Packing on a couple of extra pounds? Oh, those are just microbes
- 10,000 number of kinds of microbes the average human body contains
- six number of pounds those microbes add to your body’s weight source
» It’s not as bad as it sounds. The Human Microbiome Project, funded by the National Institute of Health, found that these bacteria can actually help us fight pathogens — those are the bad guys. This research on benign bacteria may help scientists treat, diagnose and prevent infectious diseases. You can stop washing your hands now. (edit for clarity)
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Sharing our Bodies - The Hidden Ecosystems
A very exciting Human Microbiome Project is underway in the US involving around 200 scientists from 80 research institutions who are working together for 5 years trying to map all the different microbes who live on and around us, and what their purpose are.
So far they have calculated more than 10,000 species of microbes in healthy people, and apparently there are different organisms on different parts of the body. We all share our bodies with both harmful and beneficial bacteria, and now scientists are trying to figure out why some bacteria cause infections in some people and not others.
The findings are reshaping scientists’ views of how people stay healthy, or not.
“These bacteria are not passengers. They are metabolically active. As a community, we now have to reckon with them like we have to reckon with the ecosystem in a forest or a body of water.” - Dr. Phillip Tarr, Washington University, St. Louis
To read more:
In Good Health? Thank Your 100 Trillion Bacteria
By Gina Kolata, NY Times, June 13, 2012
For years, bacteria have had a bad name. They are the cause of infections, of diseases. They are something to be scrubbed away, things to be avoided.
But now researchers have taken a detailed look at another set of bacteria that may play even bigger roles in health and disease: the 100 trillion good bacteria that live in or on the human body.
No one really knew much about them. They are essential for human life, needed to digest food, to synthesize certain vitamins, to form a barricade against disease-causing bacteria. But what do they look like in healthy people, and how much do they vary from person to person?
In a new five-year federal endeavor, the Human Microbiome Project, which has been compared to the Human Genome Project, 200 scientists at 80 institutions sequenced the genetic material of bacteria taken from nearly 250 healthy people.
They discovered more strains than they had ever imagined—as many as a thousand bacterial strains on each person. And each person’s collection of microbes, the microbiome, was different from the next person’s. To the scientists’ surprise, they also found genetic signatures of disease-causing bacteria lurking in everyone’s microbiome. But instead of making people ill, or even infectious, these disease-causing microbes simply live peacefully among their neighbors.
The results, published on Wednesday in Nature and three PLoS journals, are expected to change the research landscape.
The work is “fantastic,” said Bonnie Bassler, a Princeton University microbiologist who was not involved with the project. “These papers represent significant steps in our understanding of bacteria in human health.”
Until recently, Dr. Bassler added, the bacteria in the microbiome were thought to be just “passive riders.” They were barely studied, microbiologists explained, because it was hard to know much about them. They are so adapted to living on body surfaces and in body cavities, surrounded by other bacteria, that many could not be cultured and grown in the lab. Even if they did survive in the lab, they often behaved differently in this alien environment. It was only with the advent of relatively cheap and fast gene sequencing methods that investigators were able to ask what bacteria were present.
Humans, said Dr. David Relman, a Stanford microbiologist, are like coral, “an assemblage of life-forms living together.”
In adults, the body carries two to five pounds of bacteria, even though these cells are minuscule—one-tenth to one-hundredth the size of a human cell. The gut, in particular, is stuffed with them.
“The gut is not jam-packed with food; it is jam-packed with microbes,” Dr. Proctor said. “Half of your stool is not leftover food. It is microbial biomass.” But bacteria multiply so quickly that they replenish their numbers as fast as they are excreted.
The bacteria also help the immune system, Dr. Huttenhower said. The best example is in the vagina, where they secrete chemicals that can kill other bacteria and make the environment slightly acidic, which is unappealing to other microbes.
