Oral Bacteria and Our Health – An Evolutionary Diet Perspective

BacteriaSo if you have been reading my site (here, here, here), or any other health information recently, I know you have heard about probiotics and their benefits for our health.  What you probably haven’t heard about is the content and diversity of our oral bacteria (the bacteria in our mouths) and their impact on not only our dental health, but our overall health status.  That’s right! Another fun fact is that our diet plays a significant role in the type and diversity of the oral bacteria species in our mouth, and surprise surprise, the change in the human diet at the onset of agriculture (increase in cereal grain consumption) lead to changes in our oral bacteria and subsequently tooth decay and oral pathology.


Human Evolution & Diet

So prior to the advent of agriculture – approximately 10,000 years ago – we humans were hunter gatherers.  For simplicity sake, since it is likely much more complicated than we could even imagine, what this meant was that we did not “farm” any type of food.  We hunted animals and fish, and gathered edible vegetation where is was growing wild.  From what I understand, grains were very time consuming and difficult to process into a safely edible and somewhat nutrition state; therefore, it is likely that cereal grains were not consumed close to the extent they are today.  At the end of the day, the human diet in those days, although widely varied in macro-nutrient composition, would have consisted of the following foods: Animals, fish, seasonal fruits and vegetables (including starchy tubers), and some nuts and seeds; and don’t forget about bugs 🙂

As our species began to shift to agriculture as the major source of food production, for some reason, some very bright individual (sense the sarcasm) decided to begin to farm wheat.  Our diets then began to shift to a more soft carbohydrate containing diet.  Then, once we hit the industrial revolution, we introduced even more wonderfully processed carbohydrates such as processed grains and refined sugar. Then, fast forward to present day with the realization that high fructose corn syrup is pretty much in every processed food you can find.

Dietary Evolution and Oral Pathology Evolution

It should be obvious by now if you have ever listened to a dentist (candy is bad for your teeth), that our diets have changed for the worse with regards to dental health, not to mention health in general, but this is a topic for another day.  Not surprisingly, what is seen in the fossil record is that the remains of hunter gatherers show very little evidence of tooth decay; however, the remains of humans in early farming populations show significant evidence of tooth decay.  I have actually heard that this is one of the things archaeologists look for in remains to determine if the population they are studying were farmers of hunter gatherers.

How it All Ties to Oral Bacteria

I don’t have the best understanding of how cavities and other oral pathologies arise, it has to do with beneficial and detrimental bacteria growth in your mouth.  Increased ingestion of the types of carbohydrates listed above generates mono and disaccharides in the mouth, which are fermented by certain types of bacteria and lead to tooth demineralization because of lowered pH.  This carbohydrate ingestion/tooth decay connection is supported by the fact that the oral bacteria seen in pre-agricultural humans had a greater biodiversity than that of post agricultural humans (up to the present day).  What’s more, is that hunter gatherers appeared to have more “good” bacteria that are not associated with oral pathology than early agricultural humans and modern humans.  Even more concerning is that modern humans have an oral bacterial environment that is dominated by “bad” bacteria that are associated with oral pathology.  Guess what, in the end, as it is with many health related things, it all ties into what you eat.  #JERF

What, You Say You Don’t Care About Oral Health

So what if you have a few cavities, root canals, gingivitis, or loose teeth, your dentist can just fix it all up nicely…right? Not sure if that is the best attitude since bad oral health has been suggested as a risk factor for other conditions such as diabetes and heart disease, possibly due to the fact that it can cause a prolonged inflammatory state.  Although I would wager, based on the above, that people with poor dental health have poor diets that lead to both chronic illness and bad teeth.


Will there soon be probiotics for our mouths to prevent tooth decay and oral pathology…it would be interesting, but for me, I will just stick with eating as close to a hunter gatherer diet as I can in this day and age, and hopefully my oral bacteria will follow suit.

This whole thing has also got me thinking about how things like alcohol based mouthwash and similar products may have a negative effect on oral bacteria also (ie. similar to antibiotics and intestinal bacteria).  Interesting, and something I may look into at a later date.

Majority of the above information is from the below referenced study. 


The Barefoot Golfer

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  1. Pingback: Carnival of Evolution #61: Crustie Lovin’ Edition | Teaching Biology

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  3. Oraviva

    Really interesting article, I think you might find it interesting to watch the TED talk about Paleo diet. Also wondering what your thoughts about oil pulling for oral and overall health are?
    Oraviva recently posted…Oil Pulling Side EffectsMy Profile

  4. Jen@ Dental Clinic in Noida India

    Agree with this article. To prevent cavities and sustain good dental health, your diet, what you eat and how often you eat are some of the critical factors. Carbohydrates and sugars, if left on your teeth can greatly ruin the enamel which can lead to cavities. When you eat or drink something that has sugars the bacteria in your mouth feed on these sugars to make acids which damages your teeth. Reducing your overall carb intake cannot only give you a healthy body but also a healthy teeth.

  5. Jo

    I’ve been hearing a bit about the NZ oral probiotics called BLIS. They claim to help avert ENT type infections and sinusitis. I chatted to a person this week who bought the lozenges and converted them to a liquid to spray up his nose. He says this cured his hayfever. I was wondering if you’ve heard anything about BLIS products?

    1. The Barefoot Golfer
      Twitter: barefootgolfer1
      (Post author)

      I have not heard of the product specifically but did a bit of digging on it and it looks like it could be of benefit for oral health. Not sure about converting it to a nasal spray though as it is produced for oral use? I am not surprised about its possible benefits for oral health given current knowledge about oral bacteria and oral health ()

  6. Trusted Dentist in Bhandup

    I appreciate the author for putting great stuff on this blog.. Healthy eating habit leads to healthy and happy teeth. Thank you for sharing the article with us…


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