Ancient Tooth Plaque Reveals Dietary Decline

By Breanna Draxler | February 19, 2013 12:08 pm

Courtesy U.S. National Library of Medicine

It’s pretty standard for scientists to look at human skeletons to reconstruct past human health. But a new approach looks not at our ancestors themselves but the hardened gunk on their teeth to re-create the timeline of human dietary changes.

Scientists performed that analysis by looking at an array of ancient teeth. They found that shifts in the human diet over the millennia have led to big drop-offs in the diversity of good bacteria in our mouths—and the result is a severely weakened oral ecosystem and an increased risk of various diseases.

Saliva contains bacteria and minerals which accumulate on our teeth as plaque. Since skeletons can’t brush their teeth, this film eventually crystallizes on tooth enamel to become almost bone-like, preserving the bacterial DNA inside it. The DNA of bacteria in crystallized plaque provides a snapshot of a person’s diet, health and oral pathogens.

Scientists analyzed examples of this oral bacteria in teeth from different historic periods to see how it compared with the diseases evident in other previously studied skeletons from that time period. As it turns out, ancient hunter-gatherers actually had pretty good dental health, as evidenced by their healthy teeth and diverse bacterial populations. Things didn’t start going downhill until the Neolithic period, about 10,000 years ago.

At this point people transitioned to an agricultural society and ate mostly wheat and barley. These carbohydrates are fermentable, and encourage prolific growth of only a few kinds of bacteria in the mouth. These species overtook the others, creating a relatively homogeneous oral bacterial population.

Tooth decay and gum disease soon followed, which are visible in the skeletons. Both infections can be avoided by having a healthy mix of oral bacteria, according to the results published this week in Nature Genetics.

Then came the industrial revolution in the mid 1800s, when processed flour and sugar took over. Diets became even more carbohydrate-rich, and bacterial diversity plummeted. With less diversity in mouth bacteria, these microbiomes lost their resilience.

Today’s mouth microbiota are far less able to deal with pathogens or dietary imbalances than early humans. The result is a dramatic increase in tooth decay and gum disease: today 60 to 90 percent of children in industrialized nations have tooth decay. And researchers say the effects of this drop in diversity go beyond the mouth to make us less able to fight off systemic diseases like arthritis, heart disease and diabetes, too.

CATEGORIZED UNDER: Health & Medicine, Top Posts
  • Peter Gatliff

    Doesnt take rocket science. They were around before sugar, soda pop and candy.

  • evokerr

    Any idea about how to repopulate our mouths? I’d buy a chewing gum that diversified my oral ecosystem, and make my kids chew it.

    • Brian Valentin

      yes, eat a “paleo”lithic style diet – meats, lots of vegetables, some fruit and no wheat or grains

    • Carrie at Natural Gumption

      evokerr, there is a chewing gum that can help with the bacteria….xylitol acts as a pre-biotic, and stops the bad bacteria from proliferating….there is a whole science to it. Once you get the hang of it, it all becomes pretty simple. LMK if you want more info, I am a dental hygienist turned oral heath coach whose main focus is solving this problem for people :)

  • http://twitter.com/NinioCalle13 Ninio Calle

    The question is, are we born with diverse bacterial population initially like the ancient hunter-gatherers or not? If yes, does it mean eating a diet like the hunter-gather makes us better health-wise and live longer? If not, then perhaps we need to better have something to chew or gargle to dentally populate with diverse bacteria.

    • Carrie at Natural Gumption

      Ninio, we are born with the bacteria our familes and care givers have….if you have a balanced family history then the likely hood of you being balanced is higher. This is where the misnomer “soft teeth” comes into play….it’s really more of a bacterial issue that plagues families. Furthermore, many of the products we use nowadays are loaded with chemicals that destroy all of the bacteria both good and bad. Using the right products and the right techniques will have you healthy from year to year and families can learn to break the cycle of disease :)

  • Mandy

    Just speculating here, but it MAY be possible to populate our mouths with a more diverse microbial populations simply by eating more fruits and vegetables and avoiding the grains. Organically grown plants and preferably heirloom varieties. These plants are not sterile even after washing. If some of those non-fermenting microbes have the opportunity to establish themselves in the mouth, it could help to prevent further decay. This is just the musing of one microbiologist…………. :) I have no evidence, yet, to support it.

    • Carrie at Natural Gumption

      Mandy, yes and no…while food is an important factor, changing the bacteria matters just as much if not more. Many commercial products create a negative balance in bacteria, and knowing how to control this is the foundation to oral health! Hope that gives you some hope and insight :)

  • http://twitter.com/kstrailey Kaarle Strailey

    This is a pretty crappy summary of the actual article as it did not reflect the Euro-centricness of the study.

  • NaturalGumption

    You all have amazing thoughts on re population of good bacteria in your mouths, and yes it is 100% possible! There are some key things to understand. 1. we are infecting each other with bad bacteria…this is where generations of “soft teeth” come into play. In reality it is more likely connected to infection. Also, many of the products we use cause a shift in the natural good bacteria in our mouths.

    There is a system to wipe out the bad bacteria, help the good bacteria grow, and create balance within your mouth. It sounds too good to be true, but this is the exact reason I left the clinical world as a dental hygienist and have moved into oral health coaching (think personal trainer for your mouth)…..oral health isn’t rocket science, but it is technique sensitive. Work with an oral health coach and really get to the bottom of what is plaguing you in your mouth.

  • Carrie at Natural Gumption

    You all have amazing thoughts on re population of good bacteria in your mouths, and yes it is 100% possible! There are some key things to understand. 1. we are infecting each other with bad bacteria…this is where generations of “soft teeth” come into play. In reality it is more likely connected to infection. Also, many of the products we use cause a shift in the natural good bacteria in our mouths.

    There is a system to wipe out the bad bacteria, help the good bacteria grow, and create balance within your mouth. It sounds too good to be true, but this is the exact reason I left the clinical world as a dental hygienist and have moved into oral health coaching (think personal trainer for your mouth)…..oral health isn’t rocket science, but it is technique sensitive. Work with an oral health coach and really get to the bottom of what is plaguing you in your mouth. Feel free to contact me at http://www.NaturalGumption.com for a no charge consultation, and take charge of your oral health outside the dental office :)

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