Most Replayed Moment: Mouthwash REVERSES The Benefits Of Exercise! Dr Nathan Bryan

Dr. Nathan Bryan opens by identifying what people should stop doing rather than what they should start doing to improve their oral microbiome and nitric oxide production. He singles out fluoride as a primary concern, citing the National Toxicology Program's findings that fluoride lowers IQ in children by up to seven points, suppresses thyroid function, and is classified as a neurotoxin. He points out that most people apply far more fluoride toothpaste than the recommended pea-sized amount, resulting in significant systemic absorption through the buccal mucosa even without swallowing.

On tongue scraping, Bryan presents research showing that people who practice it have a more diverse oral microbiome and better oral health. He uses the analogy of tilling soil to explain how scraping disrupts biofilm and increases microbial diversity on the dorsal tongue. However, he warns that combining tongue scraping with antiseptic mouthwash is the worst possible scenario, as scraping opens up tissue pores and allows the mouthwash to penetrate deeper and more effectively kill beneficial bacteria.

Bryan presents a striking claim that using mouthwash eliminates the cardioprotective benefits of exercise by destroying the oral bacteria responsible for nitric oxide production. He correlates the statistic that two out of three Americans use mouthwash daily with the fact that two out of three Americans have unsafe blood pressure elevations, arguing that nitric oxide deficiency — caused by killing oral bacteria — leads to vascular constriction and hypertension.

He then discusses the bidirectional relationship between sex hormones and nitric oxide: testosterone activates nitric oxide production in men, and estrogen does so in women. This explains, in his view, why hormone replacement therapy carries cardiovascular benefits, and why low testosterone contributes to erectile dysfunction through insufficient nitric oxide-driven vasodilation.

On diet, Bryan identifies sugar as the primary dietary enemy of nitric oxide. He explains that elevated blood glucose causes glycation — sugar binding to proteins and enzymes, including nitric oxide synthase — locking the enzyme in a conformation where it cannot function. This mechanism, he argues, explains the dramatically higher rates of heart attack, stroke, peripheral neuropathy, non-healing wounds, and diabetic retinopathy seen in diabetics.

Bryan discusses beetroot's historical and scientific significance as a nitric oxide-boosting food, noting that ancient Egyptians likely drank beet juice before battle. However, he warns that most commercial beet products contain no meaningful nitrate and provide no nitric oxide benefit. He also cautions that even consuming beets is ineffective if the person uses mouthwash or fluoride, as these eliminate the oral bacteria needed to convert dietary nitrate into nitrite and then nitric oxide.

He raises concerns about the surging global use of proton pump inhibitors (PPIs) like Prilosec, Nexium, and Omeprazole, arguing that suppressing stomach acid production prevents absorption of critical micronutrients including magnesium, iodine, B vitamins, selenium, and iron. He notes that 75% of Americans are already deficient in magnesium and 95% in iodine.

On breathing, Bryan explains that nasal breathing activates nitric oxide synthase in the sinus epithelial cells, dilating bronchioles and pulmonary arteries and improving oxygen uptake. Mouth breathing bypasses this pathway and alters oral pH and microbiome composition, further shutting down nitric oxide production. He endorses mouth taping but cautions that anatomical airway obstructions must be ruled out first.

Finally, Bryan identifies humming as a nitric oxide-stimulating practice, explaining that specific frequencies activate nitric oxide synthase in the sinuses, though the optimal frequency varies by individual based on sinus volume. He also recommends 20-30 minutes of daily sunlight, noting that UV and infrared light frequencies stimulate nitric oxide release from proteins and metals, while also supporting mitochondrial biogenesis and energy production.