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Do you want to start feeling better?

Yes, Where Do I Start?

Oral Microbiome & the Mouth-Gut Axis with Dr. Steven Lin

Today we speak with Dr. Steven Lin regarding the oral microbiota and the mouth-gut axis.  We cover some very important topics, especially for those with fatigue, cavities, or who have any type of oral/dental disease like mouth lesions or bleeding gums.  Dr. Lin also shares some simple techniques that can improve the health of one’s oral airway, and therefore improve sleep.

Dr. R’s Fast Facts
  • A nutrient-dense diet is one of the best way to have a healthy mouth and healthy teeth.
  • Problems in the mouth are an indicator of disease.
  • Problems in the mouth can also cause problems with breathing and therefore cause sleep disorders. This can sometime manifest as people whose problem is not bad enough to be apnea but can cause sleep disordered breathing.  Teeth grinding can be a key indicator of this.
  • The mouth can be retrained to improve breathing, and therefore sleep.
  • If you have non-responsive fatigue, you may strongly want to consider having an evaluation for an oral disorder impeding breathing, and therefore causing a sleep impediment.
  • Problems in the mouth, like cavities, can indicate fat soluble vitamin deficiency. Vitamins such as K, D, E, and A.
  • Solely working to clean bacteria out of the mouth might be misguided.
  • Conventional mouthwashes might be a bad idea, but continue to brush and floss per standard recommendations.
  • Probiotic toothpastes may also be helpful.
  • Anyone with oral disease should be taking an oral probiotic, and consider vitamin D.
  • Dry mouth and tongue sores may indicate a very treatable form of stomach autoimmunity.
  • Dr. Steven Lin is currently the Principal Dentist at Luminous Dentistry, a dental practice on the Central Coast of New South Wales, Australia, that strives to give individuals of all ages the best possible smile.

In This Episode

The Future of Functional Medicine Review … 00:00:42
Episode Intro … 00:01:53
Mouth/Body-Health Connection … 00:06:50
Breathing and Sleep Disorders … 00:12:50
Oral Health and Energy … 00:17:20
Impactful Oral Practices … 00:20:52
The Mouth-Gut Axis… 00:24:27
Oral Hygiene Recommendations … 00:28:25
Receding Gum Line … 00:31:30
Gut-To-Mouth Connection (Autoimmunity) … 00:36:43
Oral Microbiome … 00:43:22
Episode Wrap Up … 00:46:00

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The Future of Functional Medicine Review

Dr. Michael Ruscio: Hey, guys. I just wanted to make one quick announcement before we start the show. If you are a healthcare practitioner, I’m very excited to announce that we just released the Future of Functional Medicine review. This is a monthly practitioner training tool that will allow you to sharpen your clinical skills and enhance your ability to practice cost effective functional medicine.

You’ve probably heard me say a thousand times that we need to make functional medicine more cost effective to be able to get better patient outcomes with less time and less money so that we can reach and help more people.

Well, this monthly review will be a big step in that direction. It will consist of four sections—a case study, research study reviews, the practitioner question of the month, and the practice tip. And all of this will be very helpful in making you a better clinician and steering you toward practicing a more efficacious and cost effective functional medicine model.

If you head over to, you can see a full sample issue and learn more. Again, I’m very excited about this and think you will find it, hopefully, very helpful.

Okay, back to the show.

Episode Intro

Hey, everyone. Welcome to Dr. Ruscio Radio. This is Dr. Ruscio. I am here with Dr. Steven Lin. And today, we’re going to be talking about the mouth and how the mouth connects to the gut, how the mouth connects to everything else, and some about how the gut connects back to the mouth. And it’s going to be this really interesting discussion—hopefully, really interesting, anyway—about the mouth and its impact on health. And so, Steven, welcome to the show.

Dr. Steven Lin It’s a pleasure, Michael. Real pleasure to talk to you. We were just talking about how we spoke about this connection between dental health and the gut. And I’ve been excited to talk to you about it.

DrMR: I know. And we were also remarking that we met at 2016’s Paleo Fx. And we’re almost coming up on a year from when we met and initially had said, “Hey, we should try to coordinate and find a time to record.”

DrSL: Fantastic.

DrMR: But sometimes, man, just being busy and also being in different time zones can make it challenging. But I’m glad we finally pinned this down.

DrSL: Definitely. Thanks a lot, man. It’s a pleasure.

DrMR: Absolutely. So you’re a dentist. But tell people a little bit more about your background because I know you’re doing a more, obviously, progressive, integrative, whatever-you-want-to-call-it functional medicine-like approach to dentistry, which I think is definitely important for people to learn more about this. But tell them a little bit about your background and what you’re doing within the dental world currently.

DrSL: Yes, definitely. It’s interesting you say that we’re going to talk about the mouth today and hopefully be interesting. But as a dentist, I really found that the reality and what people know about the mouth and the conventional talk on dentistry and dental health is really quite boring. Our approach to dental care is very narrow minded in terms of how we really focus on treatment.

And so I’m a dentist. I’m trained at the University of Sydney. I’m a practicing dentist in Australia. But a long time ago, I took a bit of a different path. I noticed one day that I was treating chronic, chronic disease every day of my life. And everyone had this stuff. I really didn’t have the answers as to why it was occurring.

I’m looking at the very development of our kids and people with chronic periodontal disease where their teeth are falling out of their heads. And all I was doing was treating it. I was giving them expensive and reactionary treatment plans that really didn’t get to the bottom of the disease processes.

And for me, I’m up to my wrist in saliva every day in this stuff. It seemed like there was something else going on. So that led me down the road of really trying to expand my perspective on the body and not just being a tooth mechanic.

And so it led me down the road to discovering Weston A. Price and this world of functional medicine which obviously you’re very deep in. And all of a sudden, I realized there’s actually a really logical and applicable connection between what I see in the mouth and what people are experiencing every day.

This chronic disease that we’re seeing, that we’re experiencing, as kids that were going to the dentist to have fixed throughout our lives, it’s connecting to all the other problems that we’re having—our type 2 diabetes, our obesity—all these issues that we really don’t have a good answer for in the conventional medicine set.

And it’s all starting, I think, from the mouth. And we can really model how to eat if we understand dental health better and how it connects to the body.

DrMR: And I think Weston A. Price is probably the first person, that I can think of anyway, that really opened my eyes to how important and how impactful just someone’s diet and eating a nutrient-dense diet is in terms of having a healthy mouth, healthy teeth, healthy gums, and healthy dental arch development.

And so he really helped me see that these things like children having buck teeth is probably not just a random occurrence but it may be because of a nutrient-deficient diet that doesn’t allow adequate development of the dental arch. And therefore, there is the same amount of teeth but with less space. And now you have the need for braces or cavities being a result of poor nutrition.

And if anyone listening wants to know more about that and they haven’t read Weston A. Price’s book or looked into some of Weston A. Price Foundation’s work, I would definitely recommend it because, just like Steven is saying, there are some foundational pieces with the healthy diet that are going to have a massive impact on the mouth. And I definitely want to get into some of the dietary aspects of this to help with the mouth.

But before we jump there, I’d like to start us off in an area that I think people are probably interested about which is what type of effect can the mouth have on other areas of the body? Because I’m sure people listening to this are probably listening to this from the perspective of, “Okay. I get the whole piece about wanting to eat a nutrient-dense diet.” I think most people listening are probably fairly sold on that concept.

Mouth/Body-Health Connection

But there may be someone listening, struggling with fatigue or insomnia or joint pain, and wondering if there’s a problem in the mouth that may be contributing to this. So can you launch us into a discussion in this area, Steven, in terms of what you’ve seen or the association that might be starting to be discovered in the literature or what have you?

DrSL: Yeah, definitely. And it’s a really interesting paradigm that we can take. Once we start seeing, as Weston A. Price saw, the mouth is the frame for the rest of the body. And that’s something that I realized when I saw Price’s work that I wasn’t very well trained in.

And it’s a big area of growth in the dental field now that we’re really starting to understand the jaw as this frame for our craniofacial structure, for our airways, for our spine posture. So all of these things are connected to how our teeth are developing.

And there’s an orthodontist in Portland called Dr. Dave Singh. He’s doing some great work called epigenetic orthodontics. And what he’s doing is showing our epigenetic expression and how our jaws and teeth should be developing.

And so when we see crooked teeth, he makes a really nice explanation of how it’s like building a house. You build the foundations, the pillars, the walls. And then the final thing you do is you put the furniture in. He says the teeth are like the furniture. You don’t furnish a house before you build it and design a nicely architecturally designed house.

So when we think of the teeth this way, that’s really not the approach that we’ve had. And so anyone that’s had dental development problems, it often tells me as soon as they walk into the dental office, I can see whether they’re breathing right. And oxygen really is the number one nutrient that we need. We need it in minutes. Otherwise, we pass out.

And your teeth and jaw are great indicators of whether you’re breathing right. And the big issue is that you might have breathing issues through the day that you don’t really notice. But at night, we’ve got an epidemic of people with sleep disordered breathing.

It’s something like 60 to 70 million Americans now have sleep disordered breathing. And it all begins with the jaw because our airways and musculature to support our airways aren’t developed properly because our jaws aren’t growing the way they should.

And so there’s actually a really big spectrum of that. So we probably think of the overweight male, middle aged, big neck. And they’ve got sleep apnea. They’re on the CPAP machines because they’re not breathing right. But that’s really the end of the scale.

And there’s actually a really big subset of people starting right from kids. And most kids now that come into the office have these long faces, these open mouths. Their tongues are hanging out of their mouths. They’ve got venous pooling under the eyes.

And they’re really not breathing well most of the time. But at night, they’re snoring. And they’re actually going into this apneic events where they’re not breathing right. So there’s actually a huge subset of people with sleep disordered breathing.

And by simply looking at their teeth, one of the biggest signs of this is if you grind your teeth. It’s bruxism. And the reason is that when we grind our teeth forward, so pulling the lower jaw forward, it’s an evolutionary mechanism to open up your airway. So if you’re grinding your teeth at night, it means your body is trying to open up your airways to breathe properly.

And the issue with this that there’s a syndrome called upper airway resistance syndrome. And what’s happening here is that people are sleeping, but you’re actually in a state of sympathetic activation. So your body is constantly thinking it’s in a choking response because your airways aren’t open. And so you never reach deep sleep.

And there’s a huge set of problems that go with this because you don’t reach deep REM sleep. And when the sympathetic nervous system is activated, as you know, Michael, things like digestive systems don’t work. We have anxiety and depression. And there is a whole spectrum of disorders here that are connected to simply not breathing right and how our jaws develop in the first place.

DrMR: It’s interesting you say that, because Dr. Mark Burhenne was on a while back. And one of the items that he really opened my mind up to was the connection between the oral airway, the mouth, and sleep.

DrSL: Yeah.

DrMR: And I’ll put the link in here. But we did a pretty comprehensive review of the literature on sleep. And there is almost not a condition that having impaired sleep does not correlate with. So if you want to talk about one of the most foundational things that can increase your longevity and decrease your risk of disease, morbidity, or death from a disease (mortality), having healthy sleep is one of them.

Breathing and Sleep Disorders

So certainly, this is hitting at one of the most foundational aspects of the health picture which is healthy sleep. So a question back to you then is, regarding sleep, are there certain things that people can do to fix these things?

Let’s say someone has bruxism, teeth grinding, because of malformation of the oral airway. So you have the CPAP machine, of course, if you get all the way to the diagnosis of sleep apnea. But I’m assuming there’s a fair population of people that have this subclinical sleep apnea or what’s also termed as sleep-disordered breathing.

So what can these people do? Or what other things would you suggest that people can do if they have a problem with breathing to aid with that and help improve that?

DrSL: Yeah, it’s really interesting. And it’s really starting to get the idea that oxygen is the number one nutrient. So you can actually train your body to breathe better. And there’s a subset of dentistry now that’s really interesting called biofunctional orthodontics or myofascial orthopedics where we train the musculature of our airways and mouth to breathe properly.

And the real message there is that, as humans, we are really designed to breathe through our nose. When you breathe through your nose, you expose the air to nitrous oxide which increases blood flow which increases oxygen perfusion. When you don’t breathe through your nose, you’re getting a much lower percentage of oxygen than you are when breathing through your mouth.

And if you look at your patients and you look at them at rest, most people are mouth breathing a good amount of the time. And so you can actually condition yourself [not] to breathe through your mouth. And the simple way to do that is to learn to close your mouth.

But the biofunctional way to do that is to train your airways to be open because the tongue has a huge portion of the human homunculus because there’s so much musculature. It’s like a swing that sits in the mandible of your jaw. It opens up all of the pharynx, the airway.

So training your tongue to be active and sit at the top of the roof of your mouth actually helps you to keep your airways open and strengthen the musculature of your breathing.

And the best example of this is breastfeeding. So when you think about a kid that is feeding off the breast of the mother, their tongue has to push the nipple to the roof of their mouth. And what this does is it flattens their palette out. It teaches them to breathe through their nose because their mouth is closed.

But it also trains their tongue musculature to be on. So when you see their posture, they’ve got high neck posture because their tongue is to the roof of their mouth. And they’re breathing through their nose. Then they become obligable nose breathers because of this.

And so by simply holding your tongue to the roof of your mouth just behind the front teeth you can do exercises for two to three minutes a day that trains you to be a better nose breather. And there are a lot of breathing exercises that can be done so that you’re breathing through your nose by habit rather than through your mouth.

DrMR: And so if someone wanted to learn more—if someone’s listening to this and saying, “Wow! That sounds like me,” where can they learn more about something like that?

DrSL: Yeah, so I’m going to be pulling up a lot of these exercises on my website. So just But also a great one is to talk to Steven Park. He’s the ENT. He’s got a podcast in New York. He’s really good too. There’s a lot of this sleep information on his website. So that’s

Yeah, also talk to your dentist. Sleep dentistry is really exploding now in terms of how many dentists out there are trained and have gotten extracurricular education on how to understand and diagnose sleep disorders. So talk to your dentist about it because this stuff really is out there. You can call them and ask them whether they deal with this kind of stuff.

There’s Dave Singh in Portland. There’s Dr. Mark Burhenne in California. There are a lot of dentists out there now that are practicing this stuff.

DrMR: I’m glad to see that there’s more of this because it’s always nice when we can identify a problem and then direct someone to a solution. It’s more challenging when we can identify a problem and say, “Well, we don’t really have much in the way of a solution yet.”

Oral Health and Energy

And just to throw in a few of my own thoughts here to help paint a perspective on this for the audience, if you’re someone who has some nonresponsive symptoms—and one that comes to mind that’s probably going to be most notable but not limited to would be fatigue.

If you’re someone who is struggling with nonresponsive fatigue, you’re eating well, you’re exercising, you’re getting adequate sleep, you’ve investigated any frank hormonal problems like hypo- or hyperthyroidism, you’ve made sure that your gut is healthy and you’ve taken steps to optimize your gut health, I would really put something like a good investigation in the oral health regard above doing something like repeat and very elaborate adrenal hormone cascade analyses.

And the reason for that is if you’ve done all those other things I just mentioned, you’ve removed the source of stress for the adrenals to begin with. And so testing a hormonal system that’s secondary to another problem doesn’t tell you anything about how to fix the problem.

And so I just offer that for people because one of the things I am very attuned to is patients coming in trying to pin the tail on the wrong end of the donkey. And they’re doing it without the best intent. They’ve gone out. And they’ve done some research. And they’ve heard the adrenals, the adrenals, the adrenals.

And a lot of times, the adrenal testing doesn’t tell us where the source of the problem is coming from. So if you’ve gone through some of the foundational pieces and you still have something like nonresponsive fatigue, this is definitely something I would look into because, of course, of someone at the end stage of this has sleep apnea and they start using a CPAP machine, you will see remarkable changes in someone’s energy.

So I just throw that out there as a perspective for people not to gloss over this and go to the things that seem more “scientific” because there’s a lab test that can be done in association with it and not to forget the importance of this. And I’m sure, Steven, you can probably speak to when improving someone’s oral airway musculature or retraining it or whatever you want to call it—I’m sure you’ve probably seen some pretty remarkable improvements in energy amongst other things.

DrSL: Absolutely. It’s the absolute first symptom people are describing. And headaches, this real syndrome of being exhausted all the time. And it’s so great that you say that because so many of the problems that we see in the mouth, they’re the first ones that show up. And they’re the simplest to fix as well.

DrMR: Right.

DrSL: So when we’re talking about these hormonal imbalances and things like that, if you’re treating things at the top of the funnel, you’re really getting in front of these problems rather than trying to catch them at the end. And I think that’s really what I hope for, a better conversation, like we’re having today, between dentist and medical practitioners because there are really some very easy things that we can solve simply in the mouth before they become bad problems downstream.

DrMR: Well said. And I think from a general perspective in healthcare anyway or on the functional medicine side of things I can speak to because I have the experience—I can’t speak for dentistry. But I can speak for functional medicine.

It’s usually not the highly complex answers that yield the best results. It’s really just identifying what the foundational problem or problems are and addressing those. Those are usually the things that get you the most results. And this would be a key example of that. So I definitely think we’re on the same page.

Impactful Oral Practices

And what other areas, Steven, are important? Let’s say we’re going to apply the Paret’s Principle, 80-20. What are the 20% of things in the mouth that can really yield the best results? Of course, this whole oral airway impinging upon breathing—huge. Are there other things that people should be aware of?

For example, one thing that I’ve seen pop up in the literature a few times is the association between rheumatoid arthritis and oral dysbiosis. So just throwing that out as an example. But what other things are fairly impactful in the mouth that people might want to be considering?

DrSL: Yeah, so one of the biggest signs that I see in the mouth and that I really measure in patients now—and it goes back to the Weston A. Price principles—is that it shows whether you’re getting enough of the fat-soluble vitamins.

And so disease in the mouth and disease of the hard structures of the jaw, the teeth—you just talked about periodontal disease—but it really shows whether you’re getting enough of these vitamins. And for most people that test their vitamin D and the ones that come into my practice, nearly everyone is low on vitamin D. And what this is a sign of is—your mouth and every single tooth has its own immune system. So if you’ve had tooth decay, if you’ve had some kind of growth problem in the mouth, then it’s a sign that your fat-soluble vitamins aren’t working well.

And this is exactly what Price was talking about. We’ve got a good test for vitamin D now. But all of these fat-soluble vitamins work together. And they need to be eaten together in the diet to work properly. And so we’re talking about vitamin A, vitamin K2 working in synergy with vitamin D.

And so if you’ve had a hole in your tooth, for instance, which is up to 50, 60% by the time we’re age 6, it means that your internal immune system inside your tooth isn’t working. And that’s run by vitamin D. So the little cells are run by vitamin D. So they don’t get turned on if you don’t have enough vitamin D.

And so this is really speaking to the balance of the hard structures in your body. And so that’s probably one of the first signs that things are going to go wrong. And we know, obviously, all the other issues that vitamin D deals with.

But the first sign, I think, is that it turns up in the mouth. And it’s exactly what Price talked about, eating enough of the fat-soluble vitamins and how they work together inside the tooth. So that’s, I think, really a nutritional nugget that you can find just from your dentition. If you’ve had any kind of dental disease whatsoever, it’s a good sign that you need to sort out your vitamin D and the whole set of fat-soluble vitamins alongside.

DrMR: Yeah, it makes a lot of sense. And that was definitely one of the more common threads throughout his book. And I believe the name of his book was—was it Health, Disease—I can’t even remember it. Sorry. Do you know the name of his book? Weston A. Price’s?

DrSL: Nutritional and Physical Degeneration.

DrMR: Yeah, that’s it. That’s it. Thank you. It was on the tip of my tongue.

DrSL: Yeah.

DrMR: A common thread throughout that book was the importance of fat-soluble vitamins. So that makes a ton of sense.

The Mouth-Gut Axis

What about the mouth-gut axis? So a lot of people either listening to or reading this probably have some kind of interest in gut health. And they might be wondering, “Could a problem in my mouth be dripping down into my gut?” Obviously, things flow in that direction. So what should be know about regarding the mouth-gut axis?

DrSL: Yeah, definitely. And this is the other side of it, too. So when you’re thinking about the fat-soluble vitamins, that’s your internal defense. Your oral microbiome, that’s your external environment in the mouth. And the problem with what we’ve thought about the oral microbiome is that we’ve had this really scorched-earth approach to it that we need to scrub away. And we need to eliminate with mouthwashes pathogens. And so the bacteria are bad and that they’re infections. And that really isn’t the case.

There’s actually a huge role for oral bacteria. And of course, it communicates to your gut. So oral dysbiosis is probably the first dysbiosis you’ll have because every time you swallow you’re swallowing thousands and thousands of bacteria. And studies have showed that in periodontal disease you transfer these bacteria.

And in animal models, they’ve actually brought on leaky gut just by the presence of certain species that cause gum disease. So you’re always following bacteria. But what I think and what I try to teach my patients is that microbes are doing jobs in your body.

And so a great example is with tooth decay. We know that bacteria build plaque on the teeth and the gums. And we just scrub this off. But there’s a reason for that. It’s because the oral environment is very difficult to live in. And so they build plaque.

And we call it biofilm now because they need that as their ecological niche to be able to survive. And so plaque isn’t necessarily something that we need to remove. Of course, oral hygiene stops the buildup of pathogenic bacteria.

What bacteria actually do is they’re actually transferring minerals in your mouth. They use calcium. They use minerals to build plaque. And they’re transferring this with your teeth. And so the minerals that your saliva provides go into this really ecological system of bacteria managing the calcium in your mouth.

And so tooth decay is where you’ve stripped the environment of calcium. It’s actually a lack of minerals and not a simple infection of bacteria via sugar intake.

So the sugar intake causes the dysbiosis which causes the fast metabolizing bugs to change the pH, which then removes calcium. What they do is then they need calcium to build plaque. So they go into the teeth.

And so when you see oral disease, it’s actually a dysbiosis of your oral environment. It’s not a simple infection. And what you should really be thinking is, “How do I get this back into a state of health and balance instead of simply just knocking out the pathogens?”

And that’s really, obviously, the real change of paradigm that we’ve had with the microbiome in the gut. But all of this is transferring to the rest of your body. You’re swallowing saliva every day. And the connections between things like heart disease and type 2 diabetes and rheumatoid arthritis, as you mentioned, and gum disease and oral dysbiosis really is this connection between the mouth and gut.

Oral Hygiene Recommendations

DrMR: And so are you giving different recommendations in terms of some of the basics like brushing and flossing, oral rinses, mouthwashes? I know that there are some probiotic toothpastes that are available now. I’m not sure how much effect they have or have not shown. I haven’t really reviewed any of the literature there.

Are there some key differences that you’re now making that would be different than the standard recommendation of brush twice a day, floss every day, use a mouthwash, and what have you? What’s different there, if any?

DrSL: Yeah, so in terms of the standard, I still recommend to brush and floss and twice a day, as you would normally. I don’t recommend using conventional mouthwashes simply because they take absolutely no consideration into the microbiome. And so you’re probably in the long term making your problems worse and maybe causing more problems.

To start with, I really try to drill into patients that diet is your number one defensive tool. If you eat the right things and you balance your body the right way, you cannot get dental disease.

Your systems are completely designed not to have the hard tissues, which are your teeth and your body, to get decayed, for you to have oral dysbiosis which causes the inflammation and bleeding in the gums and eventually periodontal disease.

So if you eat the right things, then these systems will all work themselves. And so really, getting your diet set is the number one thing that you need to do to get your dental health in order. And it really speaks to rebalancing your body instead of simply knocking out an infection.

But I definitely don’t recommend conventional mouthwashes. But oral probiotics have some quite good literature, certainly not as much as we know about the gut yet. But replacing a lot of the species of lactobacillus, bifidobacterium species, all these things are competitors in the mouth. So they compete against the oral pathogens.

So there’s certainly an argument if you have bleeding gums or you have gum disease or you have oral candida, certainly an oral probiotic, a lactobacillus species is good for that. Tooth decay has some good literature too because certain species compete against Strep mutans, which is the main tooth decay causing bug. So there are some really good applications.

But diet is your number one, obviously. Obviously, we’re talking about something here that’s much broader and much more thinking about our bodies as a system rather than simply filling and drilling something.

DrMR: Sure. I can totally appreciate that.

Receding Gum Line

What about receding gum line? I’ve heard that one of the major factors that can underlie receding gum line is dysbiosis in the mouth, especially in deep pockets in the gums.

And I’ve heard about some laser therapies that apparently can kill those bacteria. They seem to be somewhat efficacious, at least from what I’ve been told from different dentists I’ve spoken with about arresting the receding of the gum line. But I would be inclined to think there’s probably some sort of immune or autoimmune process that underlies that, maybe some sort of nutritional deficiency also. But any insights there?

DrSL: Yes, talking about severe periodontal disease and basically what happens there is that even from when your gums start to bleed, it’s inflammation. And it’s dysbiosis in the mouth. So it’s that loss of relationship between your oral microbiome and your immune system.

And usually, just to frame this how it happens in the rest of the body, you have to remember that your immune system is obviously being framed in your gut. So if your gums are bleeding and your dentist has told you that you have gum disease, then you likely have an issue that’s causing an overreaction of your immune system from your gut, so you should really be thinking in that territory.

But in terms of gum disease where you have these deep pockets, what happens is that you get these bugs hiding or these really nasty anaerobic, gram-negative bugs that make these periodontal pockets between your teeth and your gums. And what they do is they basically eat away at the bones that hold the teeth.

So there are some therapies. Obviously, when you have dysbiosis, you do need to rid the mouth of the pathogens. So things like laser therapy or even just periodontal root planing where you remove the pathogenic plaque. That’s usually the first step to getting things sorted out.

But you’ve got to remember the underlying dysbiosis and problem is caused by this microbiome issue. So there’s really good literature now to be replacing. Anyone with gum disease should be having a probiotic lactobacillus or bifidobacterium species. And you really should be thinking about how you feed the good bacteria.

But also periodontal disease has quite a heavy link to vitamin D deficiency. So this kind of goes back to if you have bone deficiencies in the mouth, you should definitely be thinking along the lines of your fat-soluble vitamin levels.

So I always test for vitamin D simply because most people that I see with periodontal disease have deficiency. If you think of hard tissue deficiency and the microbial imbalance which is what periodontal disease is, vitamin D usually is the main player. And there’s some good literature there showing that deficiency and gum disease are quite closely connected.

DrMR: Exactly what you just said is exactly what I was expecting you to say. When I think through this somewhat logically and I also think about this in the context of a friend of mine who has psoriasis and eats a pretty high grain and dairy diet and also has pretty bad, receding gums.

And I’ve been trying to get him on the bandwagon to give the paleo diet a solid try for 30 days and see if his skin improves or if he feels better. He also has a predilection toward inflammatory joint and soft tissue flares where he’ll work out. And he’ll be sore for a while in a tendon or ligament or what have you.

So there seems to be this inflammatory immune/autoimmune mediated type milieu in his body, especially when you look at the psoriasis and now understanding that a large component of receding gum line may also have an immune/autoimmune component to it.

And when I look at my friend, a diet that’s probably not great for underlying immune balance—high diary, high grain. Both of those have been documented in some cases to provocate. While I’m not a zealot on those dietary restrictions, I think they would also make a lot of sense in his case.

He’s also a pretty avid avoider of the sun. He doesn’t really get much sun at all. And you see a very clear picture start to emerge where this person probably needs a few dietary changes that could be quite impactful and needs to either get some sun or get some vitamin D. And that would probably have a pretty nice impact on the skin, on the bouts of inflammation, and would hopefully help arrest any further receding of the gum line.

But I’ll have to send him this recording link. I’ll either get a dirty look or some receptivity. But I love you, buddy, if you’re listening.

Gut-To-Mouth Connection (Autoimmunity)

So anyway, let’s shift over to the gut-mouth connection. I’d like to just make a quick dip into this territory because there’s something I’ve come across recently.

And for the healthcare practitioners, we will go into detail about this and provide some questionnaires you can add to your intake paperwork in one of our editions of The Future of Functional Medicine Review. So I’m going to give myself a quick plug. But I want to make practitioners aware of these things as they come up.

If you go to, you can learn more about that. But it’s a new offering that we have that’s a practitioner-specific training tool. So we will go into detail about some of this.

But essentially, when people have thyroid autoimmunity, there’s about a 30-ish percent chance they may also have autoimmunity against the parietal cells in their stomach which produce hydrochloric acid.

And interestingly, there are some oral signs and symptoms that tip you off that someone may actually have this anti-parietal cell autoimmunity which damages your parietal cells which then starts to diminish your ability to release hydrochloric acid.

Some of the main symptoms that have been documented are dry mouth and oral lesions or painful, especially burning type sensations in the mouth and/or any lesions on the tongue. And those have been documented in a fair number of these patients.

And why this is relevant is this is actually a gut problem that’s manifesting as an oral problem. And what’s most exciting to me about this is there have been now two studies done showing that administration of injectable B12 can actually arrest the autoimmunity in the stomach.

And this group—I talked about them a little while back—they actually published a follow-up study that was just released. And they found that it was only the injections that had the impact because, in their follow-up study, they gave a subgroup of patients that did not want to bother with the injections oral B vitamins. And they did not see the same impact from oral. You can make an argument that maybe sublingual dosing would have. But again, we don’t really know that.

But what we do know is that weekly injections until the antibodies became normal and then monthly injections as maintenance were able to help with oral problems but also help arrest the stomach autoimmunity that can eventually lead to a diminishment of hydrochloric acid release.

So that’s something that I think is one of the more interesting gut-to-mouth connections.

DrSL: It’s really fascinating. I think you would see these problems, people that have these really persistent gut issues. And we’re really talking as to how we can catch these things right from the beginning.

And so anything like a white lesion in the mouth, a tongue that’s swollen, a red tongue is usually a good sign that you’ve got some kind of inflammation happening and also dysbiosis because you get a lot of bacterial buildup on the tongue.

But also bleeding gums as well. I think bleeding gums is one of the first. And it’s really that sign that your gut lining and microbes really aren’t happy. So if you do have persistent gingivitis that isn’t going away from brushing, I’d really be thinking along the lines of changing your diet so that you can get your gut lining back into balance.

And just one thing that goes back a little bit too as well with the gum disease—we were talking about the periodontal pockets—is when you’re losing the collagen, the collagen that make up your gums and bones, you’re really not feeding it the right fuel to make your joints. You mentioned your friend with psoriasis and joint issues.

And so bone broth and making sure that you’re getting enough of those amino acids that you get from bones and the skin of certain animals really feeds your body the right minerals and fuel to be able to build the building blocks of your gums and teeth. And so it’s really the first sign that things might be going wrong elsewhere. It’s so interesting.

DrMR: It is. All this stuff—we could probably talk for hours, just geek out on all this stuff because it is so fascinating.

Oral Microbiome

The final area I’d like to get your thoughts on is the oral microbiome as a purview into the systemic microbiome or how we can predict the microbiome via the mouth. Unbeknownst to me, until we had a different researcher on the podcast awhile back—I believe his background was more in anthropology—and talking about how we can really predict a lot of the gut microbiome via the mouth.

So I’m curious. What do we know about this? And what might be on the horizon?

DrSL: Yeah, it’s really a horizon one because unfortunately it’s so counterintuitive. But what we know about the oral microbiome really is a lot less than what we know about the gut microbiome. I bang my head against a wall every day. It really is, I think, a huge opportunity because we can really measure the diversity and the populations of microbes that should be living in our mouths and how they relate to disease is much easier, I think, than we can in the gut.

And so a lot of the studies have shown, when you look anthropologically, that when you measure dental plaque that we’ve lost diversity in the mouth. So you can make a very simple measure of the species that are living in our mouths. And we know that we’ve also lost the same diversity in the gut.

So there are tools out there that are starting to sequence the oral microbiome. And I think that’s where we’re going to go where we can simply take a saliva sample, have a sequencing of the diversity of the oral microbiome, and have a good idea of how this is translating to the gut microbiome because the mouth is constantly translating to the mouth.

It’s how the gut microbiome is seeded in the first place in a child via breastfeeding and establishment of the oral microbiome. So they’re really not separate. They’re really related yet different parts of it and populations in our bodies.

So I think that’s a really exciting area. And we know the problems that occur due to oral dysbiosis and obviously gut dysbiosis, but connecting the two is really, I think, going to give some really functional answers like the ones you brought up before with these parietal cells that we’re going to solve some really difficult problems here.

DrMR: I hope so.

Episode Wrap Up

Steven, this has been a great conversation. Really glad that we took the time to do this. Can you tell people more about where they can track you down or connect with you?

DrSL: Sure. So ( and on social media at @DrStevenLin, no space.

DrMR: Awesome. Well, thank you again, my friend, for the time. And until probably Paleo Fx, keep on fighting to good fight here.

DrSL: Yeah. It was a pleasure, Michael. Yeah, love your work.

DrMR: Thanks, buddy. I’ll talk to you later.

DrSL: See you, man.

DrMR: Bye.

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