30 mind-blowing facts about the microbes that live inside of you

The human microbiome is as elusive as it is important. You can’t see it, but it’s teeming with trillions of bacteria, viruses, fungi, and other microscopic organisms that line vital body parts such as your intestines, mouth, and skin.

These organisms have evolved with humans for hundreds of thousands of years, and as we probe deeper into their varied roles in the human body, we’re gaining valuable insight into their essential roles in digestion, the immune system, cognition, and certain diseases.

There’s still much we don’t know about the microbiome, but the past 20 years of research have revealed some surprising facts about these tiny critters in our bodies.

Here are 30 eye-opening facts about the human microbiome, sourced from The American Museum of Natural History’s new microbiome exhibit, The Secret World Inside You. The exhibit runs in NYC November 7, 2015 to August 14, 2016.

All of your microbes combined weigh about as much as your brain: about three pounds.

And more microbial cells live inside the human body than human cells.

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The microbial genes in your body outnumber the genes in your own DNA by more than 100 to one.

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They can produce foul-smelling sulfurous chemicals in your mouth while you sleep, which, if not washed away by your saliva can cause you to wake up with 'morning breath.'

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And no two people have the exact same mix of microbes.

Research suggests that the microbiome plays a role in digestion, the regulation of your immune system, disease prevention, wound healing, gut lining protection, appetite control, brain development, and even your emotions.

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Scientists have also seen evidence that your microbial communities play a role in depression, allergies, asthma, obesity, and anxiety -- though these are just preliminary, correlative results.

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Your skin bacteria also synthesise many useful compounds for the body, including antibiotics and acids that kill other harmful microbes, and carbon dioxide, which can slow the growth of fungus.

A developing foetus is almost completely sealed off from its mother's microbes in the womb, which could be deadly to the fragile child.

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Babies born via C-section don't get bathed in good birth canal bacteria, but instead attain the bacteria from the doctor's hands or whatever else may have been lingering in the hospital room.

Scientists are experimenting with swabbing newborn C-section babies with bacteria from the mother's birth canal to replace what they missed during the delivery. If studies demonstrate long-term benefits, this may become a standard practice.

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The composition of your microbiome can change at different points in your life, with the biggest shifts occurring during adolescence, pregnancy, old age, and after a big diet change.

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