Why Your Gut Health Begins in the Mouth

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In This Article

It’s easy and convenient to think that a hole in our tooth is a simple trip to the dentist for a quick filling, then problem fixed right? Well while our dentist has been telling us how important oral health is to our body, our understanding of the mouth and its connection to the gut is showing that dental disease may be a sign of much more going on in our body than first thought.

In simplest terms, our digestive system may be imagined as a tube-like conveyor transporting food from the mouth right through to the other end. However, the more we learn about the gut, the more we understand it as less of a mechanical pipeline and more of a biological interface with the external world, much like our skin.


The colon hosts the largest population of microbes in the body with a cell density of 1011 - 1012 per milliliter of gut content. This is one of the highest numbers recorded for any microbial population on Earth and close to the number of stars in the Milky Way. 

As it turns out, microbes don’t assist in bodily processes — they are essential to its proper functioning. In the gut, microorganisms inhabit, coexist and work with human cells in a mind-boggling complex environment of biological diversity.

Living within and amongst the surface of the gut lining, our gut microorganisms serve many further purposes including capturing heavy metals, the secretion of hormones, vitamins and fatty acids that all play a role in managing the integrity of a healthy gut barrier.   

Gut Bacteria Imbalance

The consequences of a compromised gut lining are being linked to a broad spectrum of chronic diseases all over the body. Overexposure of toxins to the immune system via intestinal permeability may be a key mechanism in triggering an over-reactive immune system. It’s suggested to contribute as a precursor to autoimmune disease, and immunological haywire state of the body’s own cells occurs due to the exposure to certain antigens, for example, gluten in celiac disease.

However, a wave of new research is highlighting links between the imbalance of gut bacteria population and conditions such as inflammatory bowel disease and type 1 diabetes.

The gut’s management of neurotransmitters and connection between the digestive system and brain may associate gut bacterial dysbiosis to neurological disorders and degenerative processes such as Alzheimer’s and Parkinson’s dementia.  

The Oral Microbiome

The mouth could be considered as having the significant role of shielding gut microbes from the rest of the world.

With between 500-700 common species, the oral environment is a separate but not completely unique population to the gut. Between the two, 45% of species overlap between the mouth and colonic microbes.  However whilst the inhabitants of skin and gut vary significantly between individuals, the oral microbiome shares many more core species across human counterparts.

It’s estimated that swallowed saliva carries around a trillion bacteria into the body every day. The dental profession has long been aware of ‘bacteremia’ associated with endocarditis as well as the relationship to other systemic diseases like type-2 diabetes and arthritis. Overgrowth of harmful species in the mouth will potentially provide a continual source of these microbes to the gut, which could be the starting point of digestive imbalance.

Dental Disease and Bodily Disease

Oral conditions like dental decay aren’t simply the presence of harmful bacteria, but dysbiosis of the oral microbiome. Most significantly, this may provide a canary in the coalmine to a host of systemic disease processes. Shifts in the mouth and the food that we eat may assist to model the disruption of the gut barrier and allow us to understand diseases all over the body.

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