Why your ‘mouth microbiome’ is the new ‘gut health’

“Research continues to highlight the links between oral health and key areas like gut health, brain function, metabolic health, and immunity. Just as we’ve embraced the importance of our gut microbiome, consumers are now recognising the need to care for their mouths in the same way.”

But what actually is your oral microbiome, and how important is it to your overall health? We unpack one of 2025’s biggest health trends.

What is the oral microbiome?

The oral microbiome is the name given to the diverse community of microorganisms that live in your mouth – around 700 different varieties – comprising of bacteria, fungi, viruses and protozoa. But before you start making a panic appointment with your dentist, it’s completely normal to have all of this going on in your mouth and is in fact considered essential for maintaining good oral health.

“The bacteria in the mouth are one of the first points of immune defence that we have,” says registered nutritionist Michaella Mazzoni. “It also helps to support your teeth from decay, cavities and disease. Interestingly, gum health is linked to heart health, so taking care of your oral microbiome eventually leads to supporting your heart health, too!”

Our mouth has a whole host of varied surfaces and environments where microbes thrive, like our teeth where plaque forms, the textured surface of our tongue, our gums, our cheeks and even our saliva. And a healthy oral microbiome is key to all of this, so when it becomes imbalanced it can cause a whole host of issues.

An easy way to figure out if your oral microbiome is out of kilter is to look at whether you’re a person that suffers with things like chronic bad breath, frequent tooth cavities, sore gums, dry mouth and increased sensitive teeth.

How important is a healthy mouth for your overall health?

Like our gut, the oral microbiome is closely linked to various bodily systems, so when bacteria in our mouth are out of balance, it can rear its ugly head in other ways across the body.

Starting with the obvious, a healthy oral microbiome can help prevent oral diseases like gingivitis, periodontitis and cavities, Mazzoni tells us. “An imbalanced oral microbiome can lead to inflammation, an overgrowth of pathogenetic bacteria and increased acid which can contribute to tooth decay,” she says.

A healthy oral microbiome can also impact how your body processes food, after all digestion begins in your mouth. Poor oral health can reduce enzyme production, which are important in your saliva to help break down food. Plus, if your teeth aren’t healthy, chewing becomes less effective, which makes digestion harder for the stomach and intestines.

“Properly chewing your food stimulates digestion before your food even reaches your stomach. If you aren’t chewing your food properly, it is harder to digest them which can lead to nutrient deficiencies and bloating,” adds Mazzoni.

The connection between your gut health and your oral microbiome shouldn’t be overlooked either. Studies have explored the intricate relationship between the oral and gut microbiomes and have found that they are directly connected and can influence one another. One way this happens is when unhealthy bacteria from the mouth enters the gut when mixed with saliva and swallowed. When your immune system detects harmful bacteria from the mouth in your gut, it can cause inflammation. This long-term inflammation can be linked to heart disease, diabetes and digestive problems.

How to improve the health of your oral microbiome

Thankfully, we all have control over the health of our oral microbiome, and if it’s out of balance, there are things you can do to counteract that.

“In order to maintain healthy teeth and gums, it’s vital to brush your teeth twice a day with a fluoride toothpaste. Your toothbrush should clean one tooth at a time, but this can vary depending on the size of your teeth or toothbrush,” advises Dr Sam Jethwa, President at The British Academy of Cosmetic Dentistry. “Focus on one tooth for around three to five seconds. Once you have brushed the outside surface of the tooth, repeat from the inside of the mouth. So many people do not realise how important it is to brush their teeth from the inside of the mouth, not just the outside. Gently direct your brush along the gum line, tongue and roof of the mouth, too. You should brush your teeth for around two minutes.”

Your diet is important here, too. Fibre-rich foods and probiotics like yoghurt, kimchi and kefir all feed good bacteria. “Foods rich in fibre also help to stimulate saliva production which helps break down carbohydrates,” adds Mazzoni. This is important as many bacteria feed on carbs, especially simple sugars, and when bacteria break down these sugars, they produce acid which lowers the pH levels of your mouth and weakens enamel. This also means that limiting the amount of sugar, processed foods and alcohol you consume can also help.

Studies have also shown that saliva neutralises acids and washes away bacteria, so staying hydrated is key to good saliva production, while chewing sugar-free gum can also be a boost.

Finally, let’s not forget our good old friend cortisol. Stress raises our cortisol levels, which weakens our immune function and allows bad bacteria to thrive, while studies have found that poor sleep weakens our oral immunity, leaving us more prone to infections. So, you can add good oral microbiome to the list of what good sleep and lack of stress can do.

In short, six things to help with your oral microbiome:

1. Brush and floss daily
2. Eat fibre and probiotic-rich foods
3. Avoid excess sugar, processed foods and alcohol
4. Stay hydrated
5. Reduce stress and sleep better
6. Ensure regular visits to your dentist

Is your mouth the key to future good health?

While we all understand the importance of good oral hygiene, it’s not just about aesthetics and bad breath. There’s a reason why at your dentist appointment, they’re looking for signs of gum disease, mouth cancer and other indicators of poor health. Our mouths are the entry point between the outside to our insides, so issues with our oral health can have severe impacts on our overall health. And more studies are looking into this very subject.

Plenty of research has already found links between poor oral health and the microbiome in our mouths to cardiovascular disease, and more emerging research has found links to other areas of poor health too. A 2025 study suggests that the composition of our oral microbiome may influence cognitive health in older adults, indicating a potential connection between our oral health and neurodegenerative diseases like Alzheimer’s.

Another new study published in the International Journal of Oral Science found that disruptions to the oral microbiome (specifically the presence of a common bacteria found in the mouth), was found to be associated with the development of mouth cancer.

So, what does this mean for future developments in oral health? Personalised medicine is one area changing oral health. Some dental companies are already offering oral microbiome analysis to detect early disease risks but expect more research going into looking at custom dental treatments, microbiome testing and bacterial profiling.

In the meantime, expect to see changes in oral care products. “As this awareness grows, so does the innovation in oral care, with tailored products such as toothpastes, mouthwash and chewing gum,” says Dan Clarke from Holland & Barrett. “Brands are responding to demand for products that are multi-tasking and support long-term health, rather than just surface-level hygiene.”

Further reading

What your tongue says about your health
What foods are actually good for our gut?
Foods that can help whiten your teeth
Top 12 healthiest fermented foods
What causes bad breath and how can it be prevented?

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