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Tongue Scraping (Part I)

Today on the NutritionFacts Podcast, we take a look at some interesting facts about tongue scraping. This episode features audio from Does Tongue Scraping Cause Cancer?, Tongue Scraping vs. Tongue Brushing for Treating Halitosis (Bad Breath), and Effects of Tongue Scraping on Plaque, Gingivitis, and Cavities. Visit the video pages for all sources and doctor’s notes related to this podcast.


Today, we reveal some interesting facts about…tongue scraping, something that has been practiced for centuries in many continents around the world, but does it do anything? Here’s our first story.

Tongue cleaning can reduce the stinky gaseous compounds that cause bad breath by up to 75 percent, whereas just brushing your teeth alone may only reduce it by 25 percent. This is why tongue cleaning has the greatest priority in the treatment of bad breath. Are there any downsides?
Well, most people do not enjoy placing an object toward the back of their throats, as it can trigger the gag reflex. Tips to help prevent this include momentarily stopping breathing during tongue cleaning. You can experiment, and if the mint flavor in toothpaste sensitizes your throat to an elevated gag reflex, you may want to clean the tongue before tooth brushing. Some recommendations even suggest doing it on an empty stomach in case vomiting ensues. That doesn’t sound very pleasant, but when tongue cleaning is practiced on a daily basis, the process evidently becomes easier and less objectionable over time.
So, the main complaint of the subjects is the gagging reflex, and also, you know, tongue carcinogenesis related to mechanical stimulation. Wait! Tongue carcinogenesis means the development of tongue cancer. “These are unpleasant side effects associated with tongue-cleaning devices.” Cancer is more than an unpleasant side effect!
I know there are alcohol-containing mouthwashes, and one might expect that to predispose people to oral cancer. I talked about this in my alcohol and breast cancer video. A single sip of an alcoholic beverage—one teaspoon swished and even spit out after just five seconds—results in carcinogenic concentrations of the toxic alcohol breakdown product acetaldehyde. This is produced from ethanol in the oral cavity instantly after a small sip of a strong alcoholic beverage, and this exposure continues for at least 10 minutes after just those five seconds. And yes, this concern extends to alcohol-containing mouthwash. Researchers determined that alcohol-containing mouthwashes offer a rather low margin of safety, and that prudent public health policy should recommend generally refraining from using them. Okay, yeah, we know alcohol causes cancer, but why tongue scraping?
Well, animal experiments have shown that mechanical injuries of the tongue may be carcinogenic. Okay, even if you could extrapolate to people, are you actually injuring the tongue when you scrape it? What exactly did these experiments entail? Concerns have been raised based on an experiment in rodents showing the experimental induction of tongue cancer using carcinogenic dimethylbenzanthracene, a powerful carcinogen found in cigarette smoke and broiled meats. They evidently produced more cancer with the carcinogen if they injured the tongue using a root canal instrument. Here’s the study they cite. Indeed, scratching their tongues with essentially a little piece of barbed wire did result in more cancer, presumably because the ulceration or injury allowed for greater retention and penetration of the carcinogen into deeper tissue layers. But people don’t scrape their tongues with barbed wire. Ah, but evidently even a regular toothbrush can do it.
This appears to be the study they cite for that. But it doesn’t say a regular toothbrush, but rather “extreme mechanical stimulation.” Though then in a figure in the paper, they say just “[o]ne stroke of a dental broach was given on the tongue surface with a very light force that did not cause bleeding,” which was apparently enough to cause the cancer to show up about a month earlier. So, was it a toothbrush, extreme stimulation, or just a light scratch?
And another thing…most human tongue cancers are found on the side of the tongue, and so the relationship between tongue scraping and cancer has not yet been confirmed in humans, though there is still a possibility that mechanical stimulation may be a cause. So, I’d recommend taking it easy.
Any kind of electrical device for tongue cleaning is not recommended, but even a manual toothbrush can cause some damage, so-called micro-bleeding. Therefore, tongue cleaning should be carried out gently, with low force, to avoid unnecessary tissue trauma. Just the top surface of the tongue should be cleaned, not the sides.

In our next story, we look at what causes morning breath, and what you can do about it.

Increased public awareness and demand for bad breath remedies have resulted in a substantial growth of the breath freshening industry, and the saturation of the market with breath-improving products such as mints, chewing gum, breath sprays, and pills––the majority of which have only a short-term “masking” effect on bad breath and are essentially ineffective. Well, what can we do? Could it be as simple as swishing with some water?
Take morning breath. Malodorous breath upon awakening after a night’s sleep is a common condition known as ‘‘morning bad breath.” The most common cause of bad breath in general is the degradation of protein and protein fragments by microorganisms residing on the tongue and teeth, particularly the sulfur-containing amino acids, cysteine and methionine, that are broken down into volatile sulfur compounds like the rotten-egg gas hydrogen sulfide. Approximately 50 per cent of the adult population has early morning concentrations of these compounds in mouth air that “exceed the threshold of objectionability” established by the “organoleptic panel.” What does that mean?
“The organoleptic method is considered the gold standard in the examination of breath malodor.” Basically, all this means is some “examiner sniffs the air exhaled from the mouth and nose and subjectively defines the presence or absence of odor.” And when people’s morning breaths are sniffed, about half exceed the threshold of objectionability. Why? What causes it? A dry mouth.
Low salivary flow, particularly during the night, creates like a stagnant-pond effect, favorable for bacterial proliferation and putrefaction. And so, to reduce morning bad breath, you may read suggestions that rinsing with or drinking water upon awakening is effective, but you don’t know until you put it to the test.
“The effect of water on morning bad breath: a randomized clinical trial.” One group was randomized to rinse their mouths with tablespoon of water, and the other to drink about a cup. And…they both worked, significantly improving bad breath, with no apparent differences between them, though they didn’t have a control group, and it would have been interesting to see how much their breath improved just being awake with their normal salivary flow.
After drinking and eating in the morning, morning breath tends to disappear. People brush their teeth in the morning thinking that’s going to help, but that may only reduce rotten egg gas levels 30 percent, whereas eating breakfast works twice as well—a 60 percent drop in hydrogen sulfide levels. The mechanical action of chewing stimulates the flow of saliva, and the passage of food over the surface of the tongue removes the putrefied surface film, thus simulating the action of tongue brushing. Well, if it’s a matter of the amount of tongue coating there is, how about actively brushing your tongue, like you would your teeth? And, you get closer to a 70 percent drop, suggesting the tongue is the major source of the stinky gasses.
Other studies, though, show no benefit to tongue brushing on oral odor in both adults and children. The researchers suggest maybe the gag reflex kept people from doing a better job. What about tongue scraping? In this study, they compared tooth brushing, brushing plus flossing, brushing plus scraping, or all three. They found that adding flossing didn’t really seem to affect morning breath, and that tongue scraping won the day against tooth brushing. This suggests that tongue cleaning may be the most important hygienic procedure to reduce morning bad breath.
What about tongue brushing versus tongue scraping? Researchers compiled all the randomized controlled trials comparing different methods of tongue cleaning to reduce mouth odor in adults with halitosis and…the tongue scraping was found to be slightly more effective than tongue brushing. Perhaps the fact that the width of a toothbrush is smaller than the width of a regular tongue scraper might make it less effective in removing loosened debris from the tongue.

Finally today, we get to the nitty gritty of the best way to clean your tongue.

In my last video series on halitosis, I explored the benefits of eating a high-fiber diet for causing a reduction of halitosis. This effect is thought to be due to the “self-cleaning” of the mouth while chewing food.
However, soft foods (like how most fast food is designed so you can gulp it down) do not sufficiently scrape at the coating on your tongue, and so you can be left with a tongue coating, a whitish-gray layer of debris and microorganisms, particularly towards the back of your tongue. During the putrefaction of debris on the tongue, volatile sulfur compounds are created, like the rotten egg gas hydrogen sulfide. This putrefaction process may be responsible for up to 90 percent of bad breath. I did a video on dietary tweaks to lessen the formation of these compounds in the first place. But if you are unwilling or unable to change your diet, natural self-cleaning mechanisms might not necessarily remove the tongue coating if it’s really thick, in which case, mechanical tongue cleaning can remove debris. But often tongue cleaning is not considered a routine part of oral hygiene. Should it be? Let’s find out.
Unless you have some pocket of pus from something like periodontal disease, the most likely source of bad breath is the surface of your tongue. And it’s not like there is one bad actor bacteria. Dozens of different bacteria can produce the volatile sulfur compounds from the sulfur-containing amino acids concentrated in animal protein. That’s why probiotics may fail to change the emissions. In fact, if you compare the tongue microbiome in healthy subjects versus those with bad breath, they have almost the same bacterial composition. So, it may be less which type of bacteria you have on your tongue, and more the sheer quantity of how many bacteria you have living there. Population studies suggest that the use of tongue scrapers is associated with less severe symptoms of halitosis, but maybe those who use tongue scrapers are also more scrupulous about oral hygiene in other ways. The only way to know for sure is to put it to the test.
First, though, some background. Tongue scraping and brushing have been practiced for centuries in many continents around the world, but has been almost unknown elsewhere. “Why clean your tongue?” asked this editorial in The Journal of the American Dental Association. Dentists, hygienists, and manufacturers of toothpaste, toothbrushes, and floss have long emphasized the need to remove dental plaque from your teeth to prevent cavities. But “[w]hy do [so] many Americans produce two immaculate, shining rows of teeth separated by an organ covered with millions of microorganisms, emitting a strong malodor?”
First of all, though, what might be the effect of tongue brushing on formation of dental plaque? If you stopped brushing your teeth completely, would it matter if you brushed your tongue? No. Stop brushing your teeth, and the plaque builds up either way. Yeah, but what if you continue brushing but just add tongue brushing along with tooth brushing? That has no effect on the build-up of plaque on your teeth, suggesting that the majority of the important plaque-forming bacteria might not originate from the tongue, though another reason for not finding an effect of tongue brushing on plaque formation may be that brushing of the back of the tongue is difficult because it can make you gag.
What about gingivitis—gum inflammation? Those who clean their tongues tended to have less bleeding on probing, suggesting healthier gums, but you don’t really know if it’s cause and effect until you put it to the test. A randomized controlled clinical trial comparing tongue scraping versus no tongue scraping, and…it made no significant difference.
What about tongue scraping as a means of reducing the acid-producing bacteria that cause cavities called Streptococcus mutans? This study showed a beneficial effect, compared to using Listerine brand oral care strips or salt water rinses, but this other study found no significant effect. Maybe the population of bacteria is just so large that scraping removed only a small portion, or maybe it’s like sweeping a rug, where you’re just kind of moving stuff around. The bottom line is that studies investigating the role of tongue brushing and plaque accumulation or gum inflammation show conflicting results. So, on the basis of the medical research, there appears to be no data that justify the necessity to clean the tongue on a regular basis.
We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org/testimonials. We may share it on our social media to help inspire others. To see any graphs, charts, graphics, images, or studies mentioned here, please go to the NutritionFacts podcast landing page. There, you’ll find all the detailed information you need, plus links to all of the sources we cite for each of these topics.

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