Summary
In this second part, Dr. Michael Greger explores the cardiovascular benefits of tongue scraping through the enterosalivary nitrate pathway. He explains how dietary nitrate from leafy greens is absorbed into the bloodstream, concentrated by salivary glands, and then converted by beneficial tongue bacteria into nitric oxide, a natural artery dilator. Tongue cleaning appears to increase the proportion of these good bacteria, specifically Neisseria flavescens. Dr. Greger presents evidence that antiseptic mouthwash can significantly raise blood pressure within just one week by killing beneficial oral bacteria, while tongue scraping achieves the opposite effect by favoring the good bacteria that convert nitrate. He also covers how tongue cleaning improves salt taste sensitivity, which could help people reduce sodium intake, potentially the deadliest component of the modern diet. The episode concludes with practical recommendations on technique and frequency: scrape gently on the top surface only, include the back of the tongue, perform daily as tongue coating regrows within 24 hours, and a simple spoon works as well as any fancy device. He notes one caveat for people with artificial heart valves who may want to avoid scraping due to a small risk of introducing bacteria into the bloodstream.
Key Points
- Tongue bacteria convert dietary nitrate from vegetables into nitric oxide, a natural artery dilator
- Tongue cleaning increases the proportion of beneficial nitrate-converting bacteria like Neisseria flavescens
- Antiseptic mouthwash can raise blood pressure within one week by killing beneficial oral bacteria
- Tongue scraping improved salt taste sensitivity, which could help reduce sodium intake
- A plant-based diet boosts beneficial bacteria at both ends of the digestive tract
- Tongue coating regrows within about 24 hours, so daily cleaning is recommended
- A simple spoon is as effective as any commercial tongue scraping device
- People with artificial heart valves should avoid tongue scraping due to infection risk
Key Moments
Tongue bacteria convert dietary nitrate into artery-protecting nitric oxide
Dr. Greger explains the enterosalivary nitrate pathway where dietary nitrate from vegetables is concentrated in salivary glands and converted by tongue bacteria into nitric oxide for cardiovascular protection.
"First, we eat nitrate-rich vegetables like dark green leafies and beets. The nitrate is then absorbed into our bloodstream, and our body then pulls it out of circulation to be concentrated in our salivary glands and secreted back into the oral cavity. Why? Because our body knows there are good bacteria on our tongue to tweak it, eventually resulting in the synthesis of the artery-protecting nitric oxide."
Antiseptic mouthwash raises blood pressure by killing good oral bacteria
All human studies to date show antiseptic mouthwash has deleterious effects on blood pressure. In contrast, tongue cleaning increases beneficial bacteria that convert nitrate, offering cardiovascular benefits.
"Just a single week of antibacterial mouthwash use can cause a significant increase in blood pressure. It's not just one study, all human studies done to date have revealed deleterious effects of antibacterial mouthwash."
Tongue scraping increases salt taste sensitivity to reduce sodium intake
Research using a tongue scraper called Scrapey showed that tongue cleaning significantly increased salt taste intensity, which could help people accept lower sodium concentrations in food.
"They applied a drop of tomato soup to people's tongues before and after they cleaned their tongues with a plastic tongue scraper with the adorable name Scrapey, and they experienced a significant increase in salt taste intensity."
A simple spoon works just as well as any tongue scraping device
After reviewing various high-tech tongue cleaning patents and devices, Dr. Greger notes that the consensus group found the lowest-tech option, a simple spoon from anyone's kitchen, works just as well.
"In fact, the lowest-tech option is in everyone's home right now without buying a thing. You can just use a simple spoon."
