The Oral Microbiome: What Your Dentist Can Tell You About Whole-Body Health

Oral health is one of the most overlooked parts of whole-body prevention. In this episode, I sit down with Dr. Jonathan Levine to talk about the oral micr…

Published February 21, 202648:37The Longevity Show

You can track sleep, HRV and a hundred biomarkers and still have a blind spot the size of your mouth. Dr. Jonathan Levine — prosthodontist, inventor of the GLO Science whitening technology, and co-founder of the GLO Good Foundation with Lenny Kravitz — argues the dentist should be a first line of defence against heart disease and systemic aging, and that the separation between the two professions is a historical accident rather than a clinical one.

That accident has a name and a date. In 1840, physicians who were also performing extractions approached the first medical school and were told to go open their own — the Grand Rebuke. They did, down the street, and medicine and dentistry have been institutionally separate ever since. Levine notes that in Europe you were an MD before becoming a dentist until roughly fifteen years ago, and that Harvard remains the first medical school to house dentistry within it.

The biology closing that gap runs through one organism. The mouth is the body's second largest microbiome after the gut, and it sits at the top of the digestive tract — so swallowed saliva carries whatever lives there downward. Porphyromonas gingivalis and its breakdown products, gingipains, have been found in the amyloid plaque of Alzheimer's patients and in the carotid arteries of people with cardiovascular disease, with links now described across dozens of inflammatory conditions. The practical half covers what to actually do, in order, and one public health demand Levine wants listeners to make of their own dentist.

Before you watch

The mouth-body split is political rather than biological, and the origin story is specific. Levine calls it the Grand Rebuke: in 1840 physicians who also practised oral surgery approached the first medical school and were told to open their own, which they did down the street. Every subsequent structural feature — separate schools, separate records, separate insurance — descends from that. His counter-examples are that European training required an MD first until about fifteen years ago, and Harvard is the first medical school to bring dentistry inside it.
Levine's argument is that oral health belongs as a fifth pillar alongside sleep, nutrition, movement, and mindfulness plus social connection. His strongest evidence is airway: dentists now arguably diagnose sleep-disordered breathing better than anyone in healthcare, because the airway from the nose down through the jaws is their anatomical territory. Cone beam CT lets them see degenerative condyles, TMJ problems, nasal obstruction and airway dimensions in three dimensions.
Porphyromonas gingivalis is the organism doing most of the systemic damage, and it travels. One of roughly seven pathogens that tip the oral microbiome from symbiosis into dysbiosis, it produces breakdown byproducts called gingipains — and both have been found in the amyloid plaque of Alzheimer's patients and in carotid arteries of people with cardiovascular disease. Chronic gum inflammation produces what Levine calls leaky gums, the oral analogue of leaky gut: increased epithelial permeability letting bacterial endotoxins into circulation, where the immune system reads them as foreign invaders.
The research lineage he cites goes back over two decades. Moïse Desvarieux's INVEST work found that in people with cardiovascular disease, reducing periodontal disease reduced cardiovascular disease. A Rockefeller group led by Dana Orange showed that controlling P. gingivalis breakdown products lowered rheumatoid factor and improved rheumatoid arthritis control. And during COVID, having periodontal disease was associated with being 4.8 times more likely to end up on a ventilator — one more layer of inflammation on a system about to be overwhelmed.
Breathing through your mouth changes more than you would expect, including your face. Mouth breathing lowers nitric oxide, since the nose is the filter system evolution designed for the job. If you cannot breathe nasally, you are not reaching deep regenerative sleep. And during development, mouth breathing shapes the anatomy itself — the head tilts forward and the palate narrows into a V shape, setting up a lifetime of airway compromise. Levine points to James Nestor's self-experiment blocking his own nose, where essentially every biomarker deteriorated and then recovered once nasal breathing resumed.
The interventions for airway are more numerous than most people know exist. In children, modern orthodontics favours expansion over extraction, because widening the arch improves nasal breathing and lets the tongue sit forward, which opens the airway. In adults there are mandibular advancement devices, myofunctional therapy, laser treatments, and mouth taping as both a test and a tool — Levine notes mouth breathing is often simply a habit. He cites Sandra Kahn and Paul Ehrlich's book Jaws, built on work by the English orthodontist John Mew, who was expelled from the profession for ideas now being widely adopted.
Point-of-care salivary diagnostics are arriving, which changes what a dental visit can produce. Levine describes shotgun metagenomics identifying around 200 species with a roughly two-week turnaround, alongside newer point-of-care testing that returns three things immediately: P. gingivalis risk, MMP as an inflammatory marker informing inflammation in both mouth and body, and salivary glucose flagging possible prediabetes or diabetes. Dr. Lin's extension is that saliva may be the practical route for the broader omics revolution, since nobody wants daily blood draws.
The oral hygiene regimen has an order, and the order matters. An electric toothbrush is roughly five times more efficient than manual, because manual brushing depends heavily on technique. A water flosser delivering around 60 PSI reaches between teeth, where periodontal disease actually lives — with floss picks or string floss as alternatives, and some floss now impregnated with sodium bicarbonate. Rinses should raise pH rather than contain alcohol, because acid-loving pathogenic bacteria thrive in a low-pH mouth and acidity demineralises enamel. Tongue scraping reaches the anaerobic recesses on the tongue surface where gram-negative anaerobes and the volatile sulfur compounds behind bad breath accumulate.
Two ingredients to avoid and one to look for. No alcohol in rinses. No sodium lauryl sulfate in toothpaste, which Levine identifies as a cause of aphthous ulcers, with coconut-derived surfactants as the natural alternative. And sodium bicarbonate — ordinary baking soda — as a genuinely excellent oral health ingredient for alkalinising the mouth. He discloses direct bias here, since he co-formulated a rinse with his sons' oral care brand.
On fluoride Levine gives a dose-response answer rather than a side. At high concentrations it is genuinely a neurotoxin and causes brittle bones — a real problem in regions where groundwater carries it. At the low concentrations in toothpaste it incorporates into forming enamel as fluorapatite rather than hydroxyapatite, which is substantially more resistant to the acid Streptococcus mutans produces from sugar. He credits late-1960s water fluoridation with cutting decay rates by around 67% in young people, and predicts decay will rise as fluoride is removed. His framing mirrors the immune system: protective at the right dose, harmful when overwhelmed.
His most concrete public health ask is one sentence long: demand an oral cancer screening. Only 17 to 18% of dental practices currently perform one, and oral cancer morbidity rates have not improved in fifty years. The exam takes about a minute with a specialised light, looking for dysplastic cellular changes that can precede cancer, in areas — under the tongue, the palate — that are essentially impossible to examine yourself. He notes salivary testing for oral cancers is approaching FDA clearance, and argues patients pushing for this is what moves the profession.

Chapters

Questions

Can gum disease really affect your heart and brain?

The evidence Dr. Levine describes is considerably stronger than most people realise. Porphyromonas gingivalis, a key pathogen in periodontal disease, and its breakdown products called gingipains have been found in the amyloid plaque of Alzheimer's patients and in the carotid arteries of people with cardiovascular disease. The mechanism is that chronic gum inflammation thins the epithelium — what he calls leaky gums, analogous to leaky gut — letting bacterial endotoxins into the circulatory system, where the immune system attacks them as foreign invaders. Moïse Desvarieux's INVEST research found that reducing periodontal disease reduced cardiovascular disease in affected patients, and during COVID, having periodontal disease was associated with being 4.8 times more likely to require a ventilator.

Should I use mouthwash?

Not the conventional kind. Dr. Levine's objection is to alcohol-based rinses, and his recommendation is a rinse that raises pH instead. The reasoning is mechanistic: pathogenic bacteria thrive in an acidic mouth, and acidity also demineralises enamel directly, so alkalinising the saliva works against both problems simultaneously. Sodium bicarbonate — ordinary baking soda — is the ingredient he singles out as genuinely excellent for this. He discloses that he co-formulated a rinse with his sons' oral care brand, so the bias is explicit. His other ingredient warning is to avoid sodium lauryl sulfate in toothpaste, which he identifies as a cause of aphthous ulcers.

Why does mouth breathing matter for health?

Because it affects nitric oxide, sleep quality, and in children the shape of the face itself. Mouth breathing lowers nitric oxide levels, since the nose is the filtration system the body was designed to breathe through. If you cannot breathe nasally you do not reach deep regenerative sleep, which cascades into inflammation and blood pressure. In development the effect is structural: nasal obstruction pushes a child toward mouth breathing, the head tilts forward, and the palate narrows into a V shape, producing a smaller airway for life. Dr. Levine points to James Nestor's self-experiment blocking his own nose, where essentially every biomarker deteriorated and then recovered once nasal breathing resumed.

What's the right order for brushing, flossing and rinsing?

Dr. Levine treats this as a sequence rather than a set of options. An electric toothbrush comes first and is roughly five times more efficient than manual, largely because manual brushing depends so heavily on technique. Then interdental cleaning — a water flosser at around 60 PSI, or floss picks or string floss, since periodontal disease lives between the teeth where brushing cannot reach. Then a pH-raising rinse without alcohol. And tongue scraping, which reaches the anaerobic recesses on the tongue surface where gram-negative anaerobes and the volatile sulfur compounds responsible for bad breath accumulate. The underlying goal throughout is disrupting biofilm, which begins reforming within 6 to 24 hours.

Is fluoride safe or harmful?

Dr. Levine's answer is that it is entirely dose-dependent, and he declines to take a side beyond that. At high concentrations — as occurs naturally in some regions' groundwater — fluoride causes brittle bones and acts as a neurotoxin. At the low concentrations found in toothpaste it becomes incorporated into forming enamel as fluorapatite rather than hydroxyapatite, producing a molecule considerably more resistant to the acid that Streptococcus mutans generates from dietary sugar. He credits water fluoridation from the late 1960s with cutting decay rates by around 67% in young people, and predicts rates will climb again as it is removed — noting that in communities without access to care, untreated decay becomes genuinely life-threatening through airway closure or spreading infection.

Why do some people get cavities easily and others don't?

Dr. Levine attributes it to host response plus environment rather than luck. Host response genuinely differs between people. On top of that sit epigenetic and environmental factors: acidic drinks, sugar, alcohol drying the mouth, poor sleep and stress all shift the oral environment. Saliva normally remineralises enamel using antibodies, calcium and phosphate, but when pH turns acidic you get demineralisation instead — and that low-pH environment is precisely where the gram-negative anaerobes causing decay outcompete the commensal bacteria. He also points to what he calls fluoride babies: people who grew up with fluoride in water and toothpaste have fluorapatite-strengthened enamel that resists acid demineralisation far better. Dr. Lin offers herself as a case, having had cavities in every baby tooth growing up in Taiwan but only one filling in her adult teeth.

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