10/27/2013 11:43 EDT | Updated 12/27/2013 05:12 EST

What Your Mouth Says About You

Halloween is almost here and people of all ages will be finding new and inventive ways to conceal their normal appearance and present a façade that may scare, amuse or entice a crowd. Yet no matter how effective the disguise might be, masking hair, eye and skin colour, there will always be one aspect that cannot be hidden: the nature of one's oral microbiome.

While this may seem like a rather innocuous part of our human existence, researchers have shown the germs in a simple drop of saliva may reveal more than we might like about who we are.

When the Human Microbiome Project began back in 2007, one of the main foci was the link between germs and health. However, a number of researchers have branched off from this particular theme to venture into other areas, including personal identification either for medical or tracking purposes.

The key is the fact that the microbiome is as unique as a fingerprint and one can trace characteristics including gender and whether someone is left or right handed. When it comes to the oral microbiome, however, there has been little focus other than the fact that certain microbes may lead to diseases such as gum disease, cancer and bad breath. Yet there is far more to the story that begins with an exploration of the bones of the ancients.

Earlier this year, a collaboration of researchers led by the University of Adelaide examined the oral microbiome contained in the dental plague of ancient skeletons. They found that as the human race modernized, the nature of the oral microbiome shifted. From the Neolithic to the Industrial era, the change was not only dramatic but also could be linked to social changes including the incorporation of processed flour and sugar as well as modifications in farming practices.

This revelation suggested that differences in global society may influence the oral microbiome and explain an already observed global diversity. But was this also the same for individual lifestyle? Could changes on a global scale mean that the individual was destined to have a particular microbiome?

A team from the University of Colorado tested this theory by looking at the oral microbiome of twins from the age of 12 to 22. What they found was astonishing. Despite moving to different locations, adopting different lifestyles and in some cases, moving away from each other, the microbes in the mouth of those tested remained similar.

The paper suggested that large-scale societal changes over centuries could lead to general alterations in the oral microbiome, the nature of one's individual oral microbiome was fairly constant and based on something closer to home. That link was a person's upbringing. In essence, nurture was more important than nature when it came to the makeup of the microbiome.

This week, with this information at hand, a team from The Ohio State University revealed that the oral microbiome was based on cultural diversity, which plays an important role in the upbringing of a child. The experiments were simple: they took saliva from 192 people from four different ethnicities -- non-Hispanic blacks, non-Hispanic whites, Chinese, and Latinos -- and then identified the bacteria contained in the samples.

The data showed that the diversity between the four groups led to a unique profile -- a microbial signature -- that could highlight one's ethnic background. The data also revealed that many of the microbes detected could define the society and the individual choices, such as lifestyle.

The results of this collection of studies highlight just how much the oral microbiome tells about a person. With a simple swab of the mouth, one may be able to tell:

  • the ethnic background of individuals;
  • where they may have grown up as a child;
  • how they were brought up;
  • what kind of individual life choices have been made over the years.

While the science is still firmly situated at the lab, there is no doubt that we may be able to harness this information for improving our own lives. From gaining a personal perspective on medicine to identifying our ancestry to figuring out the best choices for lifestyle, diet and even romantic partners, we may be able to learn more about ourselves and find ways to stay happy and healthy. All from a simple swab of the mouth or by spitting in a cup.