What is the oral microbiome and how does it affect your health?

We might not eat enough veg or do as much exercise as the experts recommend, but it’s rare to find a person who doesn’t brush their teeth.

How much do you think about what lives in your mouth, though? These days we know about our gut microbiome — the bacteria that live in our gastrointestinal tract — but there is also an oral microbiome, which might be just as important for our overall health.

Research funded by the British Heart Foundation found that those with gum disease had a 69 per cent higher chance of developing type 2 diabetes, increasing their risk of heart disease. This is partly because gum disease causes inflammation that interferes with blood sugar control, but some studies suggest the heart may also be impacted by the bacteria themselves.

“If there’s an imbalance in your mouth, those bacteria can travel elsewhere in your body,” explains Dr Victoria Sampson, a dentist at the Health Society in London. “In the same way that you can get ‘leaky gut’, you can have ‘leaky gums’,” she says. “These bacteria release destructive enzymes that make blood vessels less able to dilate. It’s why we see links with high blood pressure and other issues to do with blood flow. You’re three times more likely to have erectile dysfunction if you have gum disease.”

Having poor oral health is also linked to Alzheimer’s disease. One bacterium, Porphyromonas gingivalis, originates in the oral microbiome but molecules released by it have been found in the brains of those with the disease. “It’s able to cross the blood-brain barrier and affect neurons,” Sampson says, although she is wary of identifying this as a “cause” of Alzheimer’s. “It’s such a multifactorial disease,” she says. “You might have a genetic mutation that puts you at higher risk — and there’s not much you can do about that. But oral health is one risk factor that you can address quite easily.”

Cancer is also a disease with many risk factors, and scientists have identified a bacterium called Fusobacterium nucleatum, which starts in the mouth but is found in colorectal tumours. There is also research underway on the link between the oral microbiome and other cancers, including breast cancer.

Again, if a person has poor oral health, they’re likely to have other unhealthy behaviours that could influence their health. Nonetheless, looking after your oral microbiome is just good sense. This is how to keep yours in good nick.

Keep it simple

You already know what you should be doing: brushing your teeth twice a day, avoiding (too much) sugar and seeing your dental hygienist for regular appointments.

Do invest in an electric toothbrush for a thorough clean and floss at least once a day, because 30 per cent of bacteria is in between the teeth. Curve the floss around the edge of each tooth to clean it — the thicker the floss, the better.

Tongue scraping can also remove bacteria. Use a tongue scraper made of copper, which is naturally antimicrobial, and do it first thing in the morning. Be gentle, and stop if your tongue becomes irritated.

If you want to go further, the Health Society offers oral microbiome testing to analyse the balance of bacteria in your mouth (or you can get at-home tests from thslabs.co.uk). It also offers Guided Biofilm Therapy, which is like a turbo-charged hygienist appointment, during which your teeth are coated with a purple solution to highlight the biofilm — ie bacteria on your teeth. This can then be removed before it has a chance to harden and turn into tartar. This service is widely available — ask your dentist.

An electric toothbrush will help clean your teeth more thoroughly

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Toothpaste matters

Many people try to avoid fluoride and, while there’s some evidence that it may damage the nervous system, research so far has looked at really high doses. You’d have to eat a lot of toothpaste for it to have any negative effect on your health.

Sampson does not recommend buying an all-natural toothpaste. “My patients who’ve used them come back with decay,” she says. “They don’t work, unless you’re a caveman who eats no sugar. Otherwise, if you’re not using fluoride, you need to use something like hydroxyapatite — a remineralising agent that mimics the natural mineral composition of enamel — to strengthen your teeth.”

• The secret to oral health: protecting your mouth’s microbiome

One thing you should watch out for is sodium lauryl sulphate (SLS), a foaming agent in most toothpastes. SLS strips the skin inside the mouth, disrupting the oral microbiome and causing mouth ulcers.

Dr Sampson recommends SuperTeeth toothpaste, which is free of SLS and contains hydroxyapatite and prebiotics. If £13 is too much for a tube of toothpaste, look out for the big brands doing SLS-free versions, such as Sensodyne Pronamel Extra Freshness and Colgate Total Advanced Deep Clean.

Don’t dry out

“Saliva makes the oral microbiome go round,” Sampson says. “It supplies nutrients to the good bacteria, washes away bad bacteria and helps break down sugars.”

Stay well hydrated and reduce caffeine, tobacco and alcohol where you can. If you wake with a very dry mouth, you may be a night-time mouth breather (oh dear). Some people use medical tape to seal their mouths at night, but Sampson suggests getting to the root of the problem, which might involve a trip to the orthodontist to ensure your mouth can rest comfortably closed, or a visit to an ear, nose and throat doctor to clear the nasal airways.

Feed your microbiome

Your oral microbiome loves wholesome, fibre-rich plant foods and hates sugar. Avoid free sugars in particular: those are the ones added to cakes and biscuits. There’s no need to avoid fruit — the naturally occurring sugars are balanced out with fibre and nutrients.

Fermented foods keep the gut microbiome healthy and the same is true of your mouth. Add kimchi to your sandwich or a dollop of kefir to your muesli.

• Flossing, brushing and healthy gums: how to have a perfect smile

As the evidence around the oral microbiome grows, Sampson believes that we will see how powerful it can be. Anecdotally, she sees it already. “I have patients where I’d treat their gum disease and see their arthritis getting better,” she says. “Keeping your mouth healthy reduces chronic inflammation, which is at the root of everything.”