The Oral-Body Connection: Unveiling the Interplay Between Oral Health and Overall Wellbeing

The intricate relationship between oral health and overall wellbeing is often overlooked, but emerging research continues to shed light on the profound connections between the two. Our bodies are complex ecosystems where different systems and microorganisms coexist, and any disruption in one area can have far-reaching consequences. The mouth, often referred to as the “gateway to the body,” is a critical component of this interconnected system. A growing body of evidence highlights how the oral microbiome—the diverse community of microbes in our mouths—plays a crucial role in maintaining our health, particularly through its connection to the gut and other bodily systems [1].

Understanding the Oral Microbiome

The oral microbiome is a vibrant ecosystem composed of over 700 different species of bacteria, along with viruses, fungi, and protozoa. Each person’s oral microbiome is unique, shaped by factors such as genetics, diet, hygiene habits, and overall health [2]. These microorganisms are not mere inhabitants; they actively contribute to our health by breaking down food, producing vitamins, and fighting infections [2].

However, when the delicate balance of the oral microbiome is disrupted—a state known as dysbiosis—harmful bacteria can proliferate, leading to oral diseases such as gum disease and dental caries. More importantly, dysbiosis in the oral cavity can have systemic effects, influencing the health of distant organs and systems [6].

The Oral-Gut Axis: A Two-Way Street

The gut microbiome, with its vast population of bacteria, is well-known for its impact on health, influencing everything from digestion to immune function. What is less discussed is the oral-gut axis—the bidirectional relationship between the oral and gut microbiomes [8]. The mouth and gut are the two largest microbial ecosystems in the body, and they are directly connected through the digestive tract. As Dr. Steven Lin, a prominent figure in dental health, aptly puts it, “Your mouth is the gatekeeper of your gut” [10].

When harmful bacteria from the mouth are swallowed, they can travel to the gut and potentially disrupt the gut microbiome, contributing to conditions such as Inflammatory Bowel Disease (IBD) and Small Intestinal Bacterial Overgrowth (SIBO)  [1] [9]. Conversely, a disturbed gut microbiome can influence oral health, creating a feedback loop that perpetuates disease [8].

Inflammatory Bowel Disease and Oral Health

Inflammatory Bowel Disease (IBD), which includes conditions such as Crohn’s disease and ulcerative colitis, is characterised by chronic inflammation of the gastrointestinal (GI) tract. Recent research has highlighted a strong link between IBD and oral health, with studies showing that individuals with IBD are more likely to experience poor oral health and gum disease [3].

One study found that periodontitis, a severe form of gum disease, can exacerbate gut inflammation in individuals with IBD. The study revealed that harmful oral bacteria, such as Klebsiella and Enterobacter species, can translocate to the gut, where they contribute to inflammation [3]. Additionally, immune cells known as Th17 cells, which are produced in response to oral infections, can circulate to the gut and intensify inflammation there [11].

The relationship between IBD and oral health extends beyond gum disease. Recurrent canker sores, or aphthous ulcers, in the mouth are often one of the first signs of Crohn’s disease. Dental cavities may also be more prevalent in individuals with IBD, with higher levels of cavity-causing bacteria such as Streptococcus mutans found in their saliva [4].

Stress, Oral Health, and Gut Dysbiosis

Stress is a well-known contributor to various health problems, including those related to oral and gut health. When we are stressed, our bodies produce cortisol, a hormone that can suppress the immune system and reduce saliva production [7]. Saliva plays a crucial role in maintaining a healthy oral microbiome by neutralising acids, washing away food particles, and providing enzymes that aid digestion [12].

Reduced saliva flow can lead to an imbalance in the oral microbiome, allowing harmful bacteria to thrive [6]. This state of dysbiosis can increase the risk of dental diseases such as gum disease and cavities. Moreover, stress-induced dysbiosis in the mouth can extend to the gut, as harmful oral bacteria are swallowed and potentially disrupt the gut microbiome [7].

The Impact of Diet on the Oral and Gut Microbiomes

Diet is a key factor in maintaining the balance of both the oral and gut microbiomes. The foods we eat not only nourish us but also feed the trillions of microbes that inhabit our bodies. Diets high in sugar and processed foods can have a detrimental impact on microbial diversity, both in the mouth and the gut [9].

Frequent consumption of sugar, for example, can drive down the numbers of beneficial bacteria in the mouth, leading to an overgrowth of harmful species [7]. This reduction in microbial diversity is a risk factor for both dental disease and gut-related issues. On the other hand, a diet rich in fibre-filled vegetables, whole foods, and probiotic-rich foods can support the growth of beneficial bacteria and promote a healthy microbiome [8].

Small Intestinal Bacterial Overgrowth (SIBO) and Oral Health

Small Intestinal Bacterial Overgrowth (SIBO) is a condition characterised by an abnormal increase in the number of bacteria in the small intestine, leading to malabsorption of nutrients and chronic GI issues. While SIBO is primarily associated with the gut, there is growing evidence that oral health may play a role in its development [9].

Some studies suggest that oral bacteria, when swallowed, can contribute to bacterial overgrowth in the small intestine. For instance, bacteria such as P. gingivalis and L. bacillus have been found to influence immune responses in the small intestine, potentially exacerbating SIBO [8].

The Link Between Gum Disease and Colorectal Cancer

Gum disease is not only a concern for oral health but has also been linked to serious systemic conditions, including colorectal cancer. Research has shown that individuals with a history of periodontal disease have a significantly higher risk of developing colorectal cancer compared to those without such a history [8].

One of the most implicated bacteria in this connection is Fusobacterium nucleatum, a species commonly found in periodontal disease. This bacterium is not typically present in a healthy gut but has been found in high concentrations in colorectal cancer tissues [8]. Its presence suggests that oral bacteria can influence the development of cancer in distant organs, further emphasising the importance of maintaining good oral health.

Testing the Oral Microbiome

We can now test the oral microbiome through a saliva swab oral microbiome PCR kit. It will highlight a range of opportunistic bacteria, pathogens, fungi, and normal oral bacteria that may be present in the mouth [10]. It is a valuable tool considering the impact we now know the oral microbiome has on our overall health.

Conclusion: The Mouth as a Mirror of Health

The saying “Your mouth mirrors what is happening in your body” has never been more accurate [12]. The oral microbiome is not just a collection of bacteria confined to the mouth; it is a vital component of our overall health, influencing and being influenced by other bodily systems, particularly the gut [2]. Maintaining a healthy oral microbiome through proper hygiene, stress management, and a balanced diet is essential not only for oral health but for preventing and managing systemic diseases [2].

As research continues to uncover the intricate connections between the mouth, gut, and beyond, it becomes increasingly clear that oral health should be a priority in our overall health strategy [1]. By nurturing the oral microbiome, we can promote a healthier, more resilient body, and reduce the risk of chronic diseases that stem from microbial imbalances [5].