You know the feeling you get – when you learn something new about a health problem you’ve been trying to reverse – maybe high blood pressure, diabetes, or heart disease. Well – there’s nothing I like better than bringing you the information that will help you do just that. Welcome to the NutritionFacts podcast. I’m your host – Dr. Michael Greger.
Today, we continue our series on tongue scraping. And first up – we look at how the practice can boost our cardiovascular health.
The human mouth is an important habitat for microbes––harboring up to ten billion bacteria, and no wonder. It’s all warm and moist, providing a suitable environment for bacterial growth, some of which are actually beneficial. For example, it is widely recognized that dietary nitrate aﬀords cardiovascular protection by turning into nitric oxide. And guess what contributes to the generation of nitric oxide? Our oral microbiome.
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.
We’ve got more than a billion people with high blood pressure, most of which is uncontrolled. As such, it is critical to optimize daily behaviors to support blood pressure regulation. And incorporating nitrate-rich foods may be an optimal strategy as it supports opening of our arteries via the enterosalivary pathway—the gut-saliva pathway—thanks to the friendly flora in our mouth. Dietary nitrate can provide sustained blood pressure lowering, and that starts with eating our greens. Leafy green vegetables contribute 80 percent of nitrate intake. But it doesn’t matter how many greens we eat if we have “oral dysbiosis”––if we don’t have the right tongue bugs to take advantage of them.
How can you screw up your oral friendly flora? By using an antiseptic mouthwash. Yeah, it can kill the bad bugs that cause plaque, but it can indiscriminately kill the good bugs too. And that can have systemic consequences. For example, studies show an increase in blood pressure following the use of antibacterial mouth rinses, because they reduce the protective bacteria in your mouth necessary for the nitric oxide pathway––a pathway that’s vital to blood pressure regulation and overall cardiovascular health.
Just a single week of antibacterial mouthwash use can cause a signiﬁcant increase in blood pressure. And it’s not just one study. All human studies done to date have revealed deleterious effects of antibacterial mouthwash. Okay, so what about tongue cleaning, brushing your tongue, or using a tongue scraper?
Regular tongue cleaning is recommended by the American Dental Association as a way to cut down on the bacteria on your tongue that cause bad breath. But if it wipes out those bacteria, might it wipe out the good ones too? It turns out tongue cleaning may give you the best of both worlds. Those who cleaned their tongue twice or more per day as part of their normal oral hygiene were more likely to have an increase in systolic blood pressure during use of the antibacterial mouthwash, suggesting they had more of the good bugs to kill. Here’s the graph. The mouthwash was worse for those with better tongue hygiene. So, regular tongue cleaning may result in a baseline tongue microbiome that has a greater ability to tweak nitrate, and, conversely, failure to clean the tongue daily may result in a microbiome composition that is unfavorable to nitrate conversion.
Now, but wait a second. Maybe tongue cleaning just disrupts the surface bacteria, making them easier for the mouthwash to pick off. To see if tongue cleaning was actually associated with a better oral microbiome, they did DNA analyses to elucidate the dynamics of the tongue microbiome, to compare diﬀerences between time points and tongue hygiene cohorts. And…it turns out tongue-cleaning does appear to have a signiﬁcant impact on the composition of the tongue microbiome, specifically increasing the proportion of the good bacteria. So, based on this study, tongue cleaning assumes a new importance from the perspective of blood pressure regulation, as daily tongue cleaning appears to favor the increased abundance and metabolic activity of the nitrate metabolizing species like Neisseria, whereas failure to clean the tongue daily may result in a microbiome composition that is less favorable to nitric oxide production. Now, you still have to eat your vegetables—regular tongue cleaning together with adequate dietary intake of nitrate, since that has a two-fold benefit.
First, dietary nitrate improves artery function. Eat some nitrate rich vegetables, and within three hours, an improvement of artery function. And the nitrate can also act as a prebiotic for the oral microbiome. The most abundant best nitrate converter is Neisseria ﬂavescens, and you can boost its abundance after feeding it with vegetables. After six weeks of a beet juice that’s had its nitrate removed, not much change, but after six weeks of regular beet juice and Neisseria jumps right up, making your mouth a nitric oxide-making machine.
And if you look at the association between nitrate-reducing oral bacteria and cardiometabolic outcomes, having more of these good bacteria in your mouth is linked to all sorts of cardiometabolic benefits, letting you take full advantage of the veggies you eat. What if all you ate was plants? A study on the impact of a vegan diet on the human salivary microbiome found a fully plant-based was associated significantly with more of the good Neisseria bugs that help you churn out nitric oxide. So, not only does eating plant-based boost the beneficial bacteria at the end of your digestive tract, but at the beginning too.
And eating nitrite-rich vegetables like greens doesn’t just boost the good bacteria, but beats down the bad guys––the bacteria that cause cavities, bad breath, and gum disease. And indeed, if you feed people lettuce, or lettuce juice, so you can do a randomized, double-blinded, placebo-controlled trial with a lettuce juice control that has had the nitrate removed, you can significantly improve the health of your gums with greens. The researchers conclude: “Dietary nitrate consumption may be a useful adjunct in the control of chronic gingivitis.”
So, when reviews suggest there’s no reason to clean your tongue unless you have bad breath, and in the absence of a coating on your tongue there’s no reason to clean it, that was all before these new data, which suggest additional benefits. The only caveat would be those with heart valve problems, a pacemaker, or anything else that puts you at risk for endocarditis (an infection within the heart); you may want to stay away from tongue scraping, given this case report tentatively tying the two together. Just like you can get a heart infection after tongue piercing, tongue scraping may introduce a few bacteria into your bloodstream that could be hazardous for someone at risk.
Finally today – we look at the best technique and frequency for tongue scraping.
Previously, I’ve explored how tongue cleaning may be the best way to cut down on bad breath. And it has the remarkable side-benefit of potentially helping with blood pressure regulation, as daily tongue cleaning appears to favor the increased abundance and metabolic activity of the good bacteria on your tongue that help you make your body’s natural artery dilator: nitric oxide. But there’s another way tongue cleaning may improve your blood pressure.
After two weeks of tongue cleaning, you can improve your sensitivity to tasting salt, and a follow-up study found that just a single cleaning can do it. 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 Scrapy. They experienced a significant increase in salt taste intensity. Why is that good? Because if a simple tongue cleaning could change the perceived intensity of salt, it could be used to rapidly make lower salt concentrations more acceptable to people without changing the palatability of the food. They therefore recommend that people scrape their tongue every day in order to adapt to foods with lower salt concentrations, to effectively decrease their taste for death. After all, excess sodium intake is the deadliest thing about the human diet, responsible for millions of deaths every year. So, that benefit alone could justify tongue cleaning.
Okay, so what’s the best way to do it? A systematic review and meta-analysis concluded that tongue cleaning offers benefits; however, there is insufficient evidence to recommend a specific frequency, duration, or method of tongue cleaning. But let’s see what data are out there. Tongue scraping was found to be slightly more effective than tongue brushing in treating bad breath––perhaps due to the fact that the width of a toothbrush is smaller than the width of a tongue scraper. But there are now toothbrushes on the market with a tongue scraper on the back of their head. (Here’s what they look like, and they seem to have a similar performance in terms of breath improvement.)
Some people feel that tongue brushing is more gag-inducing than tongue scraping; so, they appear to prefer scrapers. On the other hand, if you just brush your tongue, you don’t have to buy an extra gizmo.
Technique-wise, you want to make sure you include the back of the tongue, and, importantly, the cleaning should be gentle to prevent damaging your tongue. Cleaning too hard with a tongue scraper can risk for tongue injury. And you should just clean the top surface of your tongue, not the sides of your tongue.
How often should you do it? Tooth brushing should be twice a day, but the tongue cleaning recommendations seem to be more uncertain; so, researchers decided to study the rate of re-formation of tongue coatings after scraping. They took folks who had at least 20 percent of their tongue covered with a coating thick enough to conceal the pink color of their tongue. They started out with about a third of their tongue covered, and scraping reduced it to under 10 percent. The question is: how long would it take to regrow? On average, tongue coating scores had returned to baseline levels on day two; so, if tongue cleaning is to be recommended, it should probably be performed on a daily basis.
What kind of scraper is best? Researchers had people try nine different tongue scrapers. Here are the brand names; rated them using six different criteria. Meridol® and Scrapy® were the two most preferred brands out of the available options.
What’s the best way to disinfect tongue scrapers and toothbrushes? In my video on the best water purifier, I ended up speaking about disinfecting your toothbrush by soaking it in a 50:50 white vinegar water solution for 10 minutes. But this is even easier—just microwaving your toothbrush or tongue scraper for one minute. Then, you don’t have to keep buying new toothbrushes. And it’s interesting that we don’t even know exactly why it works. You’d think it’s just heat sterilization, but there must be other factors, since I nuked my toothbrush for a minute, and it hardly even got warm. But it kills off the bacteria, nonetheless.
What about all the fancy new tongue cleaners on the market? Throughout the last century, there have been many US patents on various ingenious tongue-cleaning devices. I mean, how much money can you make selling plain little cheap plastic ones? So, how about an ultrasound tongue cleaner or tongue cleaning using a high-speed vacuum ejector, or a suction tongue-cleaning device, like a tongue Roomba. But alas, a consensus group of dental professionals say there’s no evidence that substantiates the benefits of using any kind of electrical device to clean your tongue. In fact, the lowest tech option is in everyone’s home right now without buying a thing. Just use a simple spoon.
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My last two books are “How to Survive a Pandemic” and the “How Not to Diet Cookbook.” Stay tuned for Dec 5, 2023 for the launch of my one “How Not to Age.” And – of course – all the proceeds I receive from the sales of all my books go to charity.
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