What happens in the mouth does not always stay in the mouth. With every swallow, saliva travels towards the stomach and intestines, together with many microorganisms from the oral cavity. For a long time, oral flora and gut flora were considered separately. Today, it is becoming clear that both areas are connected and can influence each other.
The oral cavity is not just the starting point of digestion. It is also home to a diverse microbial community. When this balance is disturbed, it can affect more than teeth and gums. Inflammatory reactions and changes in the microbial composition can also have an effect on the whole body. To put this into perspective, it helps to look at the oral-gut axis.
What is the microbiome and why is it important?
The microbiome refers to the totality of all microorganisms that colonise a particular habitat. This includes not only the microbes themselves, but also their properties and their interactions. In the human body, this mainly concerns the gut, mouth, skin and mucous membranes.
Hundreds of different bacterial species live in the gut. They support digestion, produce certain vitamins, influence the immune system and protect the intestinal lining. As long as the composition is balanced, this is referred to as eubiosis.
When this balance shifts, it is called dysbiosis. Research links it to, among other things, inflammatory bowel diseases, metabolic problems, obesity and cardiovascular disease.
An important point for understanding this: the mucous membranes in the body do not stand alone. They are part of an interconnected system.
How does the gut microbiome develop over the course of life?
Colonisation of the gut begins at birth. Several factors play a role here, for example the type of delivery, breastfeeding, early nutrition and the use of antibiotics.
In the first years of life, the diversity of microorganisms increases markedly. Diet has a major influence on this. A fibre-rich diet supports a diverse composition. Highly processed and sugar-rich foods tend to favour a one-sided development.
The microbiome also changes in older age. Eating habits, medication, reduced saliva flow or missing teeth can play an indirect part in this. This already shows that mouth and gut should not be considered in isolation from each other.
What significance does the oral microbiome have for health?
A great many different microorganisms live in the mouth, including bacteria, fungi and viruses. They colonise teeth, gums, tongue and mucous membranes. In a healthy composition, they keep each other in balance.
Saliva supports this protection. It rinses, buffers acids and contains components that slow the growth of certain microbes.
If dysbiosis occurs, inflammation-promoting bacteria can multiply more strongly. Common triggers include high sugar consumption, smoking, diabetes or inadequate cleaning of the interdental spaces. Gingivitis and periodontitis are typical consequences.
Such inflammation can be more than a local problem. It influences the body’s defence response and can therefore also play a role outside the mouth.
How can oral bacteria reach the gut?
There are several pathways between mouth and gut through which influences can be passed on.
Swallowing saliva
Saliva containing microorganisms from the mouth is swallowed every day. Normally, only a few microbes survive the stomach acid. If the bacterial load in the mouth is very high or the stomach acid is altered, more microorganisms can reach the gut.
Inflammatory mediators in the body
Chronic inflammation in the mouth can release mediators that are distributed throughout the body via the bloodstream. This can influence the immune response and also promote inflammatory processes elsewhere.
Brief entry into the bloodstream
When the gums are inflamed, the barrier becomes more permeable. During chewing, tooth brushing or dental procedures, bacteria can briefly enter the bloodstream. As a rule, the body intercepts this, but with persistent inflammation it can occur more frequently.
Studies also show that typical oral bacteria are increasingly detectable in the gut of people with inflammatory bowel diseases. This underlines that the oral-gut axis is not merely a theoretical concept, but one that is well supported microbiologically.
How does periodontitis affect gut health?
Periodontitis is a chronic bacterial inflammation of the tooth-supporting structures. It often progresses for a long time without pain, but can gradually lead to loss of bone and gum tissue.
With periodontitis, the bacterial load in the mouth is increased. At the same time, a persistent inflammatory reaction takes place in the tissue. This can have more than local effects. Inflammatory markers in the body can rise, and the immune system remains under demand over a longer period.
In studies on chronic inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis, overlaps between mouth and gut have been observed. People with pronounced periodontitis more frequently show changes in their gut flora. Conversely, patients with gut dysbiosis or chronic bowel diseases more often report gum problems. The interplay can therefore work in both directions.
What influence does diet have on oral and gut flora?
Diet influences mouth and gut at the same time, because both microbiomes respond to similar stimuli.
Sugar and highly processed foods
In the mouth, sugar promotes acid-producing bacteria. This can attack the tooth enamel and encourage gum inflammation. In the gut, a diet high in sugar and fat can reduce bacterial diversity and support inflammatory processes.
Dietary fibre
Dietary fibre is processed in the gut by certain bacteria. This produces short-chain fatty acids such as butyrate. These can support the intestinal lining and influence inflammatory reactions. At the same time, a lower-sugar diet in everyday life helps reduce the risk of an unfavourable microbial shift in the mouth.
Dietary patterns
Mediterranean and predominantly plant-based diets are more often associated with greater microbial diversity. For many people, this is a practicable way of supporting both mouth and gut.
Can disturbed gut flora affect oral health?
The connection is not a one-way street. When the gut flora gets out of balance, this can impair the intestinal lining. As a result, inflammatory processes in the body can arise more easily or be more pronounced.
This can also show in the mouth. Patients with chronic bowel diseases more often report:
- gum inflammation
- dry mouth
- aphthous ulcers
- sensitive mucous membranes
Medication, dietary restrictions or altered saliva flow can also play a role here. Overall, it is clear: when the body’s immune regulation is under strain, this can also affect the oral flora.
How can you support oral and gut health at the same time?
A holistic approach makes sense here. Many measures work in both areas.
Everyday diet
A balanced, fibre-rich diet supports the gut flora. If you reduce sugar at the same time, this also relieves the oral flora. It does not have to be perfect. What matters are the habits over a longer period.
Consistent oral hygiene
Thorough tooth brushing and cleaning of the interdental spaces reduce the bacterial load in the mouth. Professional dental cleaning additionally helps remove biofilm from hard-to-reach areas.
Keeping the immune system in balance
Sufficient sleep, exercise and good stress management affect inflammatory processes and thus also the microbiome, both in the gut and in the mouth.
Probiotic approaches
Probiotics can be supportive in individual cases. However, they do not replace oral hygiene, treatment of periodontitis or a balanced diet. If you have questions about this, we will be happy to advise you on what makes sense in your case.
Mouth and gut are in close exchange. If you look after your oral health well, you protect not only your teeth and gums, but also support the microbial balance in your body.