Your parents probably taught you that cooperation was a good thing; that tough challenges were more easily met with the help of others. Well, Mother Nature seems to agree with that concept, and it offers us the most personal example of this imaginable: our bodies.

Right now there’s a revolution underway among biologists concerning the role of the 100 trillion (a conservative estimate) friendly bacteria that make up the human microbiome, and scientists believe that by better understanding these microbes and how they cooperate with us, we should be able to better understand how to stay healthy and why we are afflicted with certain hard-to-cure diseases.

Bifidobacterium adolescentisThe term human microbiome was coined by American molecular biologist Joshua Lederberg to describe the “the ecological community of symbiotic, and pathogenic microorganisms that literally share our body space.” Lederberg claims that these microbes have such a big influence on how our bodies work that they should be considered part of the human genome. It is estimated that a person it made up of about 10 trillion human cells, and these cells are host to 10 times more microbes, so about 100 trillion invisible passengers. This means that our bodies are not monolithic entities but rather complex ecosystems.

Various estimates put the combined weight of all these bacteria between half a pound to 2 pounds per person. So if you hold a pound of butter, that’ll give you an idea of the weight of your microbiome.

Thankfully, most of these microbes are friendly, or even symbiotic. They have co-evolved with humans, and in return for food and shelter, they provide us with a variety of services, such as fighting off unfriendly bacteria or digesting nutrients that we can’t digest on our own for lack of specialized enzymes.

This co-dependent relationship with our invisible friends has big implications for medical science. For example, we know that in certain countries where most people are deficient in certain nutrients, the average person is host to more of certain types of friendly bacteria that help produce these nutrients, compensating for the lack of them in food. Scientists are also finding links between the microbiome and chronic conditions like asthma, diabetes, obesity, multiple sclerosis and more. It’s still the early days for research in the field, but chances are that a more holistic understanding of our bodies, including the microbiome, will help us better understand ourselves and stay healthy.

Related post on MNN: Breathing soil bacteria makes you smarter

Michael Graham Richard ( @Michael_GR ) Michael writes for MNN and TreeHugger about science, space and technology and more.

Say hello to your 100 trillion invisible friends (aka friendly bacteria)
Many of the bacteria an average person carries with them are friendly and even symbiotic because they have co-evolved with humans.