The Human Microbiome
The term ‘human microbiome’ refers to the collection of microorganisms (bacteria, fungi and viruses) that inhabit our bodies, taking up residence in various tissues, cavities and body fluids. These microscopic hitchhikers are vital to our health, helping to break down food, protecting against germs, processing toxins and even producing vitamins.
Six Pounds of What?
There are around one trillion microbes in or on the human body and bacterial cells actually outnumber the cells in the body by ten times. It is estimated that the average human body contains 10 to the 14th power bacteria and up to 160 different species of bacteria. Taken all together, this could be up to 6 pounds of bacteria that we host in our bodies.
A Delicate Balance
While there is some evidence that the fetus is first exposed to microbes in utero, the GI tract of the newborn infant is sterile. Newborns becomes quickly colonized soon after exposure to the world around it. The composition of the human microbiome evolves throughout infancy and childhood and can be affected by many factors including diet, illness and use of antibiotics.