The Belly Button Harbors Large Amounts of Bacteria

Micro bacteria from our belly buttons could be considered a defense mechanism against pathogens.

A study looking deeply into the interior of the human belly button has discovered hundreds of organisms living right inside this tiny space.  The belly button harbors large amounts of bacteria, and is home to at least 60 species of fungi, bacteria, and yeast, according to this recent investigation.

Even though this investigation found 60 to 70 species in the average person, they found more than 1,400 in general, showing massive differences between individuals, according to Professor Rob Dunn, of the University of North Carolina.

Dunn and his colleagues have gathered, up to now, bacteria from naval skin of 391 subjects.  Men and women of different ages, ethnic backgrounds, and even different hygiene habits were included in the study.  The investigators focused not only on bacteria contained in the samples, but they also discovered some interesting fungi and yeast as well.

Scientists have confirmed the viability of these organisms through cultures, and are now in the process of DNA sequencing for each species.  The preliminary results indicate that the number of organisms per person varies greatly.

Until now, no clear explanation was known as to why people differ so much in terms of bacterial communities.  The differences that were upturned in this study do not easily coincide with gender, ethnicity, age, or even frequency of bathing.  This is about something else.

Investigators, however, came to the conclusion that a group of relatively few bacteria species are shared among the majority of people; there are hundreds of rare species that a few people here and there possess.

According to Dunn, it’s quite possible that the majority of us share common species, but that the rare species found are a measurement of individual history, and are inherently unpredictable.

These bacteria are a defense

The belly button harbers lots of bacteria

The investigators decided to study the belly button, in part because they tend to harbor so many organisms that are frequently unaltered by bathing, lotions, ultraviolet light, among other things.

While a lot of people can now be more aware of washing their belly button, Dunn says that these organisms can also be found on our forearms, hands, and frankly, all over the surface of the body, and they play and important role.

They are our first line of defense against pathogens found on our bodies.  They are like an army that lives on our skin that, when they find a new pathogen, their first instinct is to fight against it.  A human being that has successfully washed the microbes off their body could be at high risk of suffering from a mortal skin infection.

They change our behavior

In one study, Professor Elizabeth Archie, from the University of Notre Dame, and her collegue Kevin Theis analyzed microbial communities in humans and similar animals.  They found that bacteria can even change the behavior of those who harbor it.

As an example, steroids and other natural chemical products are found under the armpits. These compounds are the primary products of bacterial metabolism, and can give rise to all sorts of odors that affect the way we interact with others.

For instance, Corynebacterium metabolizes testosterone to produce musk, an odor similar to urine.  Others metabolize tallow and sweat to produce an odor similar to onion.  According to these studies, there is ample evidence demonstrating that bacteria produce strong odors, and that armpit odors serve as a recognition sign among human beings.

These signs seem to help us distinguish individuals.  Mothers, for example, have no problem recognizing their children by simply smelling their armpit.  Even with these family ties, our most intimate relationships in life are those still mysterious and minuscule organisms.

Photo courtesy of Jorge Anguita