The microbiome is not just located in the gut — our bodies actually host dozens of microbial communities. “Think of the body as a world with all these different habitats where microbes live,” says Athena Aktipis, PhD, an evolutionary biologist at Arizona State University. These are a few of the other habitats in your body.
The mouth is a microcosm of distinct microbial communities. A few hundred types of bacteria live on the tongue, the roof, and the insides of the cheeks. A 2009 Swedish study found some of these microbiota have a nitrate-regulating effect, which may help protect against ulcers and lower systemic blood pressure.
Scientists used to think the lungs were sterile, but they have recently discovered that a small population of microbes lives there, including migrants from the mouth and airborne travelers. Researchers have found associations between changes in the lung microbiota and diseases like chronic obstructive pulmonary disease (COPD), asthma, and rheumatoid arthritis, but studies have not proven causality.
Some 1 trillion bacteria reside in our three major skin terrains: oily, moist, and dry. Microorganisms show environmental preferences. Fungi, for instance, like to cluster near our ears and forehead and not strictly near the feet, as you might think. Overall, skin microbes protect us against pathogens and parasites and assist in wound healing. Disruptions to the skin microbiota are associated with skin disorders, such as psoriasis, atopic dermatitis, and acne.
Blinking and tears make the eyes a tough environment for microbes, but a small number of bacteria and other microbes manage to live there and are thought to protect against infection. The diversity of the eye microbiota is changed by contact use, which can lead to an infection called keratitis. Studies suggest that the condition known as dry eye is associated with alterations in the eye microbiota.
The microbiome of the vagina varies among women, and even within one individual there is enough day-by-day fluctuation to make researchers dizzy. What they know so far: These organisms protect women from potentially pathogenic organisms, including those that cause vaginosis, yeast infections, sexually transmitted infections, and urinary-tract infections.
Did You Know? A 2015 study at the University of Oregon found that our bodies emit millions of bacteria into the air around us. This “microbial cloud” contains a unique, identifiable signature that lingers in the places we’ve been, so we literally leave our mark wherever we go.
This originally appeared in “Build Your Microbiome” in the July/August 2017 issue of Experience Life.