The Mouth-Gut Axis: Why Bacteria and your Teeth Are Key to Digestive Health
Ahead of his new book The Dental Diet launching on the 9th January, Dr Steven Lin hops in to tell us about the microbes in our mouth and how ruddy well important they are.
As a dentist, I’ve noticed some big problems with the way we approach our oral health. Everyone would be familiar with the advice we should be brushing, flossing and using mouthwash.
But simply removing microbes from our mouth may be missing some important roles of the bacteria that live amongst our teeth.
You’ve probably heard a thing or two about the gut microbiome, like how it can influence mood, weight, and everything in between. With study after study confirming the gut’s connection to the brain, the heart, and even the liver,
The oral microbiome, on the other hand, is much less spoken about. Why is that?
The oral microbiome sets the stage for everything that’s to come. So, the healthier your mouth and oral microbiome are, the healthier your gut, immune system, and entire body. Let’s brush up on a few of the basics:
1. Your mouth is the gatekeeper of your gut.
Think of the digestive tract as a river, with the mouth being the source of that river. This means that every time you swallow, you’re swallowing thousands of bacteria—some bad but, most importantly, some good. Contrary to what you’ve been told, the goal isn’t to kill off all the germs in your mouth. In fact, just like the gut microbiome, there are good bacteria in your mouth that aid the health of your teeth and the rest of your body.
Probiotic strains of bacteria are known to perform protective functions in the mouth. For example, some strains release acids that keep the harmful bacteria that cause tooth decay under control. Others protect against strains that cause gum disease and bad breath. Unfortunately, we’ve been taught to abuse the delicate environment in our mouths, often turning to harmful antibacterial mouthwashes that wipe out all the good bacteria that our microbiomes need to thrive.
2. Your mouth is the mirror of health and disease in the body.
The gut microbiome determines so much of our health and well-being, like our mental health and weight. It even contributes to degenerative diseases like dementia. But it’s the opening to the intestinal tract—the oral microbiome—that is essential to keeping the gut healthy! Let’s refer back to our river. The oral microbiome flows beyond the mouth and down the digestive tract, to become the gut microbiome. And it’s there, deep in our digestive system, that microbes become profoundly important to the overall function of our body. Could a problem in your mouth, like gum disease and inflammation-causing bacteria, be dripping down into your gut?
Studies show a clear link between oral disease and systemic disease, with oral pathogens having been found in rheumatoid arthritis, inflammatory bowel disease, and even cardiovascular disease. That means when we look to oral care first, we’re quite literally halting disease in its track.
Simple carbs like sugar and flour don’t cause as much damage to our teeth as most of us think. Rather, it’s how they reduce the diversity of our oral microbiome that causes problems. The body is in constant communication with the gut about what’s coming into it from the outside world. And while the gut calls most of the plays, the playbook is largely written in the mouth. When your mouth and oral microbiome are healthy, diverse, and thriving, the rest of your body will thrive, too.
How do you ensure that you have a balanced and diverse oral microbiome?
While brushing and flossing twice a day is critical, diet is your No. 1 defensive tool. The next time you sit down to a meal, remember that you’re responsible for feeding trillions of tiny microbial lives with what’s on your plate, so you’ll want to choose wisely.
Here are some pillars to help you choose oral-microbiome-friendly foods:
- Remove processed foods, which are full of preservatives and artificial additives.
- Eat whole foods that haven't been altered from their original state.
- Ditch sugar in all its forms: high-fructose corn syrup, maple syrup, table sugar, added sugar, refined sugar, honey, etc.
- Ditch the juices, even if they're 100 percent fruit. They are a concentrated hit of simple carbs.
- Head to the farmers market and eat seasonal and locally sourced foods.
- Eat a variety of fiber-filled veggies. Some of our favorites are Brussels sprouts and leafy greens.
- Replenish your microbiome with fermented and probiotic foods.
- Choose veggies—like onions and chicory root—that contain prebiotic fiber, which is known to specifically feed beneficial bacteria.
- And finally: Chew! Your mouth is the beginning of the digestive system, and eating on the run can starve the beneficial bacteria of their role in kick-starting the food processing.
Steven Lin is a board-accredited dentist, and is a speaker and author. Frustrated by the dental profession's limited approach to treating without addressing the cause of disease, Steven Lin merged anthropological, physiological and nutritional science with oral health to integrate effective prevention strategies into his dental practice. He is the dental expert for I Quit Sugar, the online platform of bestselling author Sarah Wilson. www.drstevenlin.com