How Your Mouth Controls Your Gut

By Dr Steven Lin

How Your Mouth Controls Your Gut
Science shows your mouth is the gatekeeper of your gut.

In the past several years, we’ve learned that our whole body is actually filled with bacteria that it needs to stay healthy. And the mouth and teeth are no exception. Our mouth is in a permanent partnership with bacteria that help maintain our teeth and gums and also our mouth’s immune system. Tooth decay is a sign that the bacteria in the mouth are imbalanced, and it can also be a sign of trouble in the rest of the body.

The Mouth-Gut Axis: How Oral Bacteria Dictate Your Body’s Health

Bacteria play a role in managing more than our teeth. The oral microbiome flows beyond the mouth and into 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.

The simplest way to look at the human gut (digestive tract) is to imagine it as a tube-like conveyor belt that takes food from the mouth, processes it to create fuel, and then gets rid of the waste products through the opposite orifice. But the more we learn about the gut, the more we understand that, much like our skin, it’s an organ that influences and contributes to crucial physiological processes throughout the body.

Instead of the more straightforward job of protecting us from the outside world, like a wall, our gut has to do a lot more nuanced work and a lot more multitasking. The gut has to trans¬port, digest, and absorb nutrients while filtering out contaminants that shouldn’t get into the bloodstream. On top of that, it has to signal to the rest of the body what‘s coming next.

The size of the gut should give you an idea of how big a job this all is. It has a surface area of approximately 32 meters squared, and if you unfurled the digestive tract and laid it out flat, it would roughly cover half of a badminton court.

All of our organs and blood vessels and our entire gut are lined with epithelium cells. These cells act as a sort of gate that either allows outside molecules to pass through to the rest of the body or refuses them entrance. For an additional layer of protection and insulation, the gut is also lined with a layer of mucus that hydrates and nourishes the intestinal cells.

But as we’ve only recently discovered, the gut has something else to help it do its many jobs: a vast population of microflora— bacteria, viruses, fungi, and even more obscure organisms— that live in the gut lining. These living microorganisms serve as another protective barrier for our insides; they produce compounds that kill off potentially harmful bacteria, filter out damaging materials in food like heavy metals, and stimulate mucus production.

Your Mouth Is The Gatekeeper Of Your Gut

The fact that your gut is filled with trillions of bacteria might be a little overwhelming. But what goes on in the gut is really just a continuation of what happens, on a smaller scale, in your mouth, where your microbiome starts. The mouth acts as the first gateway to the gut microbiome, and it continues serving it throughout life. Every time you swallow saliva, you’re sending thousands and thousands of bacteria to your gut.

No less than 80 percent of the body’s immune cells live in the digestive system. The gut produces more antibodies than any other organ. When harmful microbes (whose molecules are similar but not identical to friendly gut microbes) try to invade the gut lining, our gut bacteria seem to help our immune sys¬tem by sending messages that pass through the gut lining. These messages tell immune cells to bind to the harmful microbes, eat them, and dispose of them.

But gut bacteria don’t just influence immune cells in the gut. They can also send messages to immune cells in distant parts of the body. For instance, parts of the microbes’ cell walls, which are made from an amino acid and sugar mesh called peptidoglycan, can activate immune cells located in bone marrow, in addition to other parts of the body. Research has also shown that when bacteria in the gut consume fiber, they produce fatty acids that help manage the immune system and even metabolism.

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. The healthier your mouth and oral microbiome, the healthier your gut, immune system, and entire body.

Extracted from The Dental Diet, by Dr. Steven Lin, January 2018, RRP AU$24.99, Hay House


Print Recipe


Let us keep you up to date with our weekly MiNDFOOD e-newsletters which include the weekly menu plan, health and news updates or tempt your taste buds with the MiNDFOOD Daily Recipe. 

Member Login