Who did you last kiss?

Not a quick peck on the cheek. A real kiss 💋

You shared more than affection.

You shared 80 million bacteria, instantly reshaping your oral microbiome.

Why does that matter?

Because this oral bacteria may influence your heart, fertility, even your aging brain.

Gut this. Kombucha that. But no one talks about the mouth.

So how do you protect your oral microbiome (aside from choosing your kisses wisely)?

The oral-gut microbiome axis

Your mouth is home to over 700 species of bacteria living on your teeth, gums, tongue, and cheeks¹ .

It’s crowded in there. In fact, your mouth hosts the second-largest community of microbes in your body, just behind your gut.

But your mouth and gut aren't separate - they’re connected, forming one continuous ecosystem.

Every swallow moves bacteria from your mouth to your gut. If the oral microbiome is unbalanced (in dysbiosis), harmful bacteria can also invade your gut.

Your mouth’s link to chronic disease

When your oral microbiome is out of whack, it can cause a host of issues; heart disease, diabetes, arthritis, Alzheimer's, and even pregnancy complications.

This is because when your gums are inflamed (periodontitis), harmful bacteria and inflammatory substances enter your bloodstream² .

Once inside, these periodontal pathogens travel around your body, triggering chronic low-grade inflammation. This systemic inflammation has been well-documented, damaging organs far from your mouth³ .

Bacterial toxins even reach your bone marrow, pushing it into overdrive. More immune cells are produced, amplifying inflammation and causing widespread damage.

What messes up your oral bacteria?

Sugar

Every time you sip a sugary drink or snack on something sweet, you're not just feeding yourself, you're feeding the bacteria in your mouth.

Certain “cariogenic” bacteria (literally meaning cavity-causing), thrive on sugars like fructose, sucrose, lactose, and even simple starches found in many processed foods.

These bacteria stick tightly to your teeth, forming a sticky layer of plaque.

As they digest available sugars, they produce acid. This acid slowly dissolves your tooth enamel, leading to cavities and decay.

Saliva

Your saliva isn't just water, it’s a powerful mix of immune cells, enzymes, and minerals that protect and repair your teeth.

Throughout the day, your mouth naturally shifts from acidic to neutral. This allows saliva to rebuild tooth enamel and balance your oral microbiome.

But frequent snacking and sipping sugary drinks keep your mouth constantly acidic, weakening teeth and letting harmful bacteria thrive.

Having a dry mouth makes this even worse.

To promote protective saliva:

• Stay hydrated by sipping water regularly. Add a pinch of salt/ electrolytes to boost mineral content and aid remineralization of your teeth.

• Chew Xylitol gum to stimulate saliva. Xylitol is a great sugar alternative as oral bacteria can't metabolize it.

• Breath through your nose rather than your mouth. Use mouth taping at night to encourage nasal breathing while asleep.

• Chew firm, real foods instead of processed snacks. This strengthens your jaw muscles, improves saliva production, and overall oral health.

Toothpastes, mouthwashes and whitening

Brushing or mouthwash breaks up plaque (biofilm) on your teeth.

But common dental products often 'carpet-bomb' your mouth, killing both good and bad bacteria.

Alcohol-based mouthwashes (e.g Listerine) have even been linked to oesophageal and colorectal cancers, as they wipe out good bacteria, leaving “opportunistic” bad bacteria to thrive⁴ .

Chlorhexidine mouthwashes (e.g Colgate Savacol) reduce overall microbial diversity, which actually increases your risk of tooth decay⁵ .

And beware of green-washing. Even natural-sounding ingredients like essential oils can be overly antimicrobial if used too much, damaging the healthy bacteria in your mouth⁶.

At-home whitening also wipes out mouth bacteria. If you choose to use it, do so sparingly. It takes about 30 days for your bacteria to bounce back⁷ .

Flossing and beyond

Flossing cleans periodontal pockets (the spaces between your gums and teeth), but tongue and cheek surfaces also harbor bacteria.

Tongue scraping removes 75% of bacteria vs. 40% by brushing alone⁸.

Choosing the right toothpaste and mouthwash

When selecting toothpaste and mouthwash, think gentle.

Avoid harsh mouthwashes with alcohol or strong essential oils. Try saltwater rinses, baking soda, or oil pulling instead. This gently reduces bacteria and freshens breath.

Skip toothpastes with Sodium Lauryl Sulfate (SLS). This can cause or worsen mouth sores⁹ .

Choose toothpaste with hydroxyapatite, a natural mineral that safely rebuilds enamel without fluoride. Hyroxyapatite has even been shown to outperform fluoride in some studies¹⁰.

Probiotic toothpastes¹¹ also help keep your mouth’s bacteria balanced.

Kissing, babies, and bacteria

A single 10-second kiss can transfer around 80 million bacteria¹² .

Sounds alarming, but this can be healthy.

Sharing diverse bacteria improves your oral health (especially if your partner’s oral microbiome is in ‘eubiosis’, aka balanced and healthy).

But for parents, especially new or expecting moms, bacterial exchange matters even more.

Babies aren’t born with tooth-decay bacteria, they acquire oral microbiota from caregivers via kissing, sharing spoons, pre-chewing food and even their delivery method (vaginal births give babies a more diverse microbiome early on¹³ ).

Breastfeeding further boosts oral bacteria, adding good bacteria (like Lactobacilli) through skin contact and breastmilk¹⁴ .

Pregnant moms, take note: your hormones make your gums more sensitive, increasing your risk for gum disease. Severe gum disease can even lead to premature birth and lower birth weight¹⁵ .

Starting healthy oral habits from day one gives your child the best shot at lifelong wellness.

Test your mouth’s health

You can now test your microbiome directly, and discover exactly which bacteria are living in your mouth.

Your mouth isn’t isolated. It shapes your gut, heart, brain, and even your future children’s health.

Keep your mouth balanced, your dental products simple, and kiss wisely.

✅ Oral Microbiome Checklist

◻️ Brush gently (twice a day, soft-bristle brush)
◻️ Floss daily (to be extra: brush first, floss, and then brush again)
◻️ Scrape your tongue every day - clean your cheeks and gums, too
◻️ Practice oil pulling 2-3 times per week minimum, coconut oil based¹⁸
◻️ Consider probiotic toothpaste or supplements
◻️ Choose gentle toothpaste (with hydroxyapatite, avoid SLS)
◻️ Avoid harsh mouthwashes (try saltwater, baking soda, or coconut oil pulling instead)
◻️ Stay hydrated (sip water throughout the day, add electrolytes)
◻️ Avoid sugary snacks and drinks (chew Xylitol gum instead)
◻️ Eat firm, real foods to boost saliva production
◻️ Breathe through your nose, especially at night (try mouth taping safely)
◻️ Visit your dentist every 6 months for check-ups and cleanings, every 3 months if diabetic or immunocompromised
◻️ Test your oral microbiome periodically
◻️ Use probiotics if you discover you’re in dysbiosis

Reviewed by Julija Rabcuka, BA(Oxon), MSc. 

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