The foreign press have recently picked up on a new ‘craze’ in Japan: cosmetic dentistry for yaeba, or, as I like to call them, fangs.

The above photograph is a very extreme version, but many Japanese people have overlapping or wonky teeth.

Although it might look like an orthodontic horrorshow to Americans, it’s considered cute to have a couple of yaeba, and some dentists have apparently started services to actually make them rather than correct them. One theory is that being slightly ‘imperfect’ makes girls less intimidating and easier to approach, while this post points out that it feeds into an infantilised sexuality: crowded or jumbled teeth are more common in children, making women with them look younger.

Why do people in Japan have such bad teeth? If you look around in a crowd here, the odds are you’ll see a horrifying variety of gnashers; from fangs to crumbling, yellow and brown incisors, enormous overbites, and some so jumbled they look like a handful of popcorn. I once taught a student who appeared to have two rows of teeth, with some literally protruding from their palate.

It’s not just aesthetic concerns that make overcrowded mouths a worry, however. A wonky line of teeth is difficult to clean, and much more susceptible to decay— many of the ‘hidden’ front teeth I see in Japan are yellow or brown. Tooth decay has been linked to dementia, heart disease, pneumonia and “poor pregnancy outcomes”, not to mention general infections that can be lethal without treatment.

Modern dentistry tells us that dental health is all a matter of brushing, restricting sugar intake, and calcium. When you think about it, however, this makes little sense. OralB and Colgate haven’t yet reached all 7 billion souls on the planet, and yet many indigenous—and, yes, impoverished—people have perfectly white, straight teeth. So what gives? Why do  people who brush thrice daily and drink milk have worse teeth than those who do little other than floss with twigs, while living off carb-heavy diets and often no dairy?

The answer is that in comparison to people eating traditional diets, those consuming ‘modern’ diets in industrialized nations actually bear the epigenetic effects of poor nutrition: small, narrow skulls and dental arches that cramp their teeth. A lack of sufficient vitamins and minerals (namely D, A, calcium, magnesium, iron and zinc) leads to mineral starvation, which in turn causes inadequate bone formation. This can happen in just one generation, but its deleterious effects can also be passed from inadequately nourished parents to their children.

One would think that wealthy people with an access to a variety of foods would be better nourished than, say, a hunter-gatherer community living hand to mouth. Yet there is evidence that our teeth and health in general took a turn for the worst with the advent of agriculture. Farming may have created crop stores that freed people from a subsistence lifestyle, leading to a division of labour that allowed for the development of government, philosophy, architecture and the arts… but we paid for it with our teeth.

Agricultural crops— grains, beans, legumes and nuts— are not only nutritionally inferior to most of the animal or plant foods that constitute hunter-gatherer diets, they also contain anti-nutrients in the form of phytic acid, which inhibits the uptake of minerals such as calcium, magnesium, iron, phosphorus and zinc.

Fortunately for our ancestors, an enzyme called phytase that neutralises phytic acid is present wherever phytic acid is. Careful preparation— such as soaking, fermentation or grinding/milling— can increase the amount of phytase and thereby reduce phytic acid and its damaging effects. Unfortunately, however, most people don’t bother with these traditional techniques any more and tend to eat their nuts raw, their rice and bread brown, and their legumes unsoaked. Modern vegans and vegetarians, who tend to eat more of these foods than omnivores, are particularly at risk of not absorbing the minerals and vitamins they eat as a result.

Phytic acid means that, contrary to the prevailing wisdom, wholegrains are not actually better for you, as the acid is concentrated in the fibrous husk. Apart from taste, this is possibly the reason that traditional cultures began to mill or grind their grains. Traditional diets are generally sound because they are based on the accrued knowledge of generations and observations of the cause and effect of diet. (This is why no society or culture has ever been vegan by choice).

Despite that, populations who depend on agricultural crops for the bulk of their diet tend to have smaller skulls and inferior bone structure to peoples that live off wild food.

This document clearly shows this with skulls found in Fukuoka dating back to Japan’s Jomon period (hunter-gatherers) and the Yayoi period (when rice cultivation began):

Skull from late Jomon period (left) vs skull from middle Yayoi period (left)

True, the teeth in the Yayoi skull are straight and well-spaced— but it’s noticeably narrower, setting the trend from then on.

Many people assume that the traditional Japanese diet is based around raw fish, rice and vegetables, but this is a fallacy. Even sushi was originally made from fermented fish, and while fishing was no doubt an important part of food culture on the coast, people living inland would have had little access to it. Rice also became the sole staple relatively recently; before that, many ate a mixture of grains, including barley (mugi) and buckwheat (soba), and supplemented this staple with fermented soybeans in the form of miso, natto and soy sauce, and pickled vegetables. Taboos on eating meat came as early as 675 AD thanks to Buddhist beliefs, and the majority of calories came from grains (in 1873, 55% of the daily intake of 1,850 came from rice; in 1960 the average Japanese person ate an astonishing 1000 calories of rice a day, or 120 kilos a year, twice what they do now).

In the West we say “Man cannot live on bread alone.” In Japan, the semi-mystical importance given to rice means that many believe it’s possible to get by without much else. (Disproved by cases of beri-beri in soldiers fed only white rice.) The high value given to rice is probably because its cultivation caused a population explosion and it provided easy calories. But rice is not terribly nutritious. It is superior to wheat in that it is hypo-allergenic (whereas those with celiac disease cannot eat wheat) and it also has less phytic acid. White rice has even less, but lacks the vital B vitamins from the husk. Consuming most of your calories from rice and not enough foods rich in vitamin D, A, K2 and minerals such as calcium, magnesium, iron, phosphorus etc, leaves you wide open to nutritional deficiencies— and yes, bad teeth.

You might ask why this is not common knowledge. I have no idea, particularly when research into the role of diet in dental health was conducted as early as the beginning of the 1900s by Weston A. Price, an American dentist who traveled the globe to find the secret to perfect teeth, and Sir Edward Mellanby, a doctor who uncovered the link between vitamin D and dental/bone health, both of whom had success with diets containing cod liver oil (high in vitamin D and A) in treating dental cavities. Price’s life work took him to Scotland, Australia, Switzerland, New Zealand, Peru, Eskimo tribes in Canada, Amazonian Indians and tribesman in Africa.

The diets varied immensely; from a heavy dependence on dairy in the Swiss village where he started his research— unpasteurized milk, butter, cream and cheese with rye bread, occasional meat, bone broth soups and a few summer vegetables— to the Maasai in Kenya, who subsisted largely on milk, blood and meat, with some vegetables.

Price noticed that when people broke away from their traditional diets and began to eat flour, sugar and other ‘industrialised’ foods, their faces changed. His photographs show this clearly:

Aborigines living in modern environments

Price argued that modern foods were at the root of most of the West’s nutritional deficiencies and structural bone problems such as narrowed jaws and noses, overbites, lack of cheekbones, pinched nostrils, and weak chins. He attributed modern conditions such as allergies, anemia, asthma, poor vision, lack of coordination and behavioural problems to poor diet.

Although the diets of the people Price visited varied hugely, he postulated the existence of ‘activator X”, now presumed to be vitamin K2, which works synergistically with vitamin D to place calcium where it belongs–in the bones and teeth–and out of the soft tissues, where it does not.

While Price did not realise the importance of phytic acid inhibiting the uptake of minerals, Dr. Mellanby discovered that the rate of cavities in children’s teeth plunged and the rate of healing soared when they stopped eating oatmeal and ate a diet heavy in animal products, potatoes and vegetables instead. Have a look at this for a more detailed explanation of the diet and the mechanisms behind it.

This all means that anyone who has wonky teeth was either malnourished to some extent or had ancestors who were. That yaeba are seen as attractive in Japan therefore bucks biological explanations for the rules of attraction that argue we evaluate partners on their genetic potential to bear healthy children. That said, if you have gone and married Goofy, you could do your children a favour by swopping bread for some nice liver and onions.

Nutritional content of 1,400 calories of bread
Nutritional content of 1,400 calories of beef liver, AKA nature’s multivitamin

To read more about this, click on the embedded links, or read the two most important articles on phytic acid and Dr. Mellanby’s research into vitamin D, phosphorus and tooth decay reversal

16 responses to “Gnashers.”

  1. I thought it was just lack of dental hygiene at some points. But you know if you have good nutrition, your teeth are so strong (specifically the dentine and enamel layers) that they don’t require too much brushing. It’s ‘soft’, badly formed teeth that are vulnerable to decay.

  2. I am a bit insulted by this article. I disagree that “wonky” teeth are bad. I am American and raised in a culture where “perfect” teeth were ideal. For years my “wonky” teeth embarrassed me but my dentist said they were healthy. My best friend too also had “wonky” teeth, we both did not believe in forcing our teeth into alignment so they could be perfect. Yet, because of Western culture of being surgically perfect, we tried to learn to smile with our mouth closed or cover them with our hands when other Americans would look our mouth. Now in Japan I can smile freely, happily and without embarrassment. My teeth are beautiful here. While I was living in America, I was raised in the countryside, so our food was mainly beef and farm fresh vegetables, perhaps my ancestors had poor nutrition. Either way, I am proud of my teeth, they are not bad but “wonky” and beautiful.

    • My point was not that “wonky” teeth are unattractive; it was that the alignment of one’s teeth and general dental health are dependent on diet, and that many are unaware that anti-nutrients in grains and so on can reduce their absorption of minerals and vitamins.

      I think it’s fine, even admirable to not bend to society’s standards of perfection, but severely misaligned teeth are actually a health issue because they are harder to clean and more vulnerable to decay.

      I have far from perfect teeth myself. I had braces for two years to straighten them out, but the bottom ones still cross over and I have fluorosis from some misguided dentist giving me fluoride tablets when I was little. I was pescetarian/vegetarian for ten years and my teeth were chipping a lot before I stopped eating most grains and started eating meat. Fortunately I didn’t follow in the steps of my father, who had over 40 fillings/caries.

      I agree that it is nice not to be discriminated against in Japan for your teeth, but I also wish that people were more aware that their health is dependent not only the amount of minerals/vitamins in the food they consume, but also the amount of mineral inhibitors in their diet. Unfortunately vegan doctrine seems to be taking over mainstream nutritional advice and the danger of wholegrains and low-fat diets are being overlooked.

      One thing I perhaps should have mentioned in the article is that although the Japanese diet is thought of as healthy because it’s low fat, eating brown rice, white fish and vegetables means that fat-soluble vitamins such as A, D and K are not absorbed as well. Add in the aversion to sunlight (e.g. vitamin D) and you have a recipe for bad bone health.

  3. Thanks for the interesting article; have lived in Japan for years and mused this with friends, and though a Brit, my teeth have always been straight, but I’d never read about the effect of diet so much. Thanks

  4. “The answer is that in comparison to people eating traditional diets, those consuming ‘modern’ diets in industrialized nations actually bear the epigenetic effects of poor nutrition: small, narrow skulls and dental arches that cramp their teeth. ”

    Doesn’t that mean that ALL modern industrialized nations have this problem (as the picture of the New Zealand kids shows)?
    Shouldn’t the japanese have a much higher rate of “tooth decay” TOGETHER with the “crooked” teeth to even begin to try to fit them in this theory?
    Not to mention that the japanese are not the only rice loving country in the world.
    Vietnam for example? Do they sport the “crooked” teeth look?

    I think it is just that japanese just don’t do that many surgical interventions on their teeth.
    Or reversely, as Carmilla puts it, some countries are obsessed with “perfect” teeth.
    Cultural not dietary.

    • You’re missing the point somewhat. All modern industrialized countries do have this problem to some extent because of diets low in minerals and/or high in mineral inhibitors, which are found in agricultural crops. Japan’s traditional dependence on rice to the exclusion of nutrient-dense foods (due to a historical taboo against animal products, little tradition of keeping livestock, and low availability of fish for those living inland) means that it may be worse off than other countries. I am not very knowledgeable about Vietnam but I think that they have eaten meat throughout history. Even the poorest of the poor who rely on broths made with bones are getting more nutrients than a meal of rice/miso soup/vegetables. Koreans, likewise, have much better teeth than the Japanese because of the higher proportion of animal products in their diet. The other thing, as I wrote in my reply to Carmila, is that a low-fat Japanese-style diet inhibits peoples’ ability to absorb fat-soluble vitamins (A, D and K, all the important ones for teeth), which might make the Japanese worse off than other countries where rice is a staple.

      You don’t necessarily have to eat animal products to have good teeth. They help because they are more nutritionally dense (e.g. more vitamin A, D, E, iron, phosphorus, calcium etc) and eating them means you usually eat less grains, which inhibit your ability to absorb minerals.

      I don’t have data on it but I think a historically undernourishing diet has produced more dental deformities in Japan than there is in, say, Germany (all that cheese and sausages seems to be doing them okay). You are right, however, that it is a cultural thing not to straighten out misaligned teeth with braces and retainers.

      I think the girls at the top are pretty cute too… it’s just in spite of their teeth, not because of it. 🙂

  5. I must add that I’m from Brasil, where “perfect” teeth are valued just as much as in the USA (I actually had my teeth corrected as a teenager).

    I have been learning japanese using japanese TV for listening practice.
    In the beginning I had the same “orthodontic horrorshow” reaction.
    But as I brainwashed myself in JP TV I started to change my opinion as time passed, and now I think those girls in the the pics are very cute, thankyouverymuchsir.
    So again: I think it is cultural.

  6. I forgot to thank you for writing the interesting post and providing many interesting reference links. Most people don’t bother with references, so: thanks.

  7. Great article! I knew I had inherited my crowded mouth from my dad’s side, but had no idea it was an Anglo-Saxon trait. I am definitely very grateful (in retrospect, after years of agony) that I had 4 molars extracted and my teeth straightened when I was a teenager. My yaeba were pretty cute but did make teeth-brushing terribly hard work!

    It’s interesting that eating white rice/bread is better for your teeth; I think the main argument for eating brown rice/bread remains, however, that they have a lower GI.

    I understand that the custom of covering your mouth when you laugh goes back to the Heian period, when women covered their teeth because they looked yellow in comparison to their powdered white faces – hence the fashion at the time for blackened teeth…

  8. this is super sugoi resarch. so impressive.

    I will give you a hint that might help you understand why some people in japan like overlapping or wonky teeth.

    in my personal theory, that is because some people do not want perfection in women. because look at social structure. so many stress oppress people. if you marry with super perfect woman, some people might get more stress by acting super perfect man. all people are not perfect, just trying to be perfect, i guess.
    this is not about sex discrimination, or egoism. it might be about chemistry in feelings, or just animal instinct….. i guess…….
    they just want to hang out with woman without super tension.
    if you don’t have so much stress, you can hang out with perfect man or woman. because you like that way. perfect women or men tend to force you stay cool all the time, or giving you impression of have to stay cool. so, some people tend to like woman who have some kind of defects(sorry, this word could be inappropriate), does not matter whether it is super shrilling voice or personality.
    maybe you could understand this sense, if you walk around at midnight. there are so many drunk people abandoned on street, and no one in japan say you can’t be too drunk in public place. because they have their own personal territory which they do not want to be intruded, and many people have some kind of sympathies for that, i guess.
    I know it might cause bipolar results. for example, good thing about being a bit different from other culture is create new trend, bad thing is create too bad or too far or sometimes makes things impossible to understand. i guess, japanese people enjoy balance(i am not 100% sure about things i mention here. i am not sociologist).
    but, once all these componets get together, it creates new technology or gadget or trend or whatever often, i guess. i do not have a answer for whether this way is right or not. and i do not want to talk about top down & hierarchy structure, revolution, NGO, or NPO things either in here.
    moreover, we do not have horror story like a vampire or dracula in deep roots. so, we do not associate it with them so often. and also many people do not believe in religion.

    of cause, some women do not care their appearance much, some do, some overdo, some do surgery, some can’t afford to do. that’s it

    by the way, i have a question, are those scientific evidences, nutrient things, and decay tooth linkage shown above are true? do you know how they measure?

    i am not expert in any fields, but i always doubt about these kind of evidences. i once tried to read a book about how scientist measure these nutritious fact, but impossible to understand…..

    i think these nutrient thing might be true(sorry about using word might so often).
    but, you can’t control which way your tooth grow, it could be genetic thing, or lack of biting, or lack of exercise, or lack of speaking, or lack of trying to pronounce words correctly, or lack of eating macrobiotic veggie & balanced diet, or tilt your face badly on bed, or just mysterical statistical science….

    i know some rich people who should have had good food(because their skin is perfect, and have good teeth alignment), and had straighten device? or bridge?(i don’t know the name), when i was primary student.

    as a conclusion, some people feel comfortable staying with someone who have bad tooth. i don’t have wonkey tooth, but, i have two artificial front tooth, due to……. w.

    for your information, you should not use too much toothpaste, when you brush. and also it is not good to use minty toothpaste you can get from everywhere. (but, i use it, w.). i don’t know the scientifical evidence, but i heard from someone who works as assistant dentist before.
    Moreover, why some people get tooth decay or cavity easily is depend on how much sugar?(sorry, i don’t remember name) your saliva contains. each person have different levels of amount. therefore, bad tooth can not be prevented by brushing tooth 100 times a day. i heard from dentist.
    but,, in this sense, good nutrient could be the answer…….? i do not know.

    anyway. lastly, i like this kind of wonder X wonder stories, so it would be super great if you notice wonder in japan and write about it more.

    looking forward to seeing your new wonder!

  9. While you’ve presented some scientific or quasi-scientific sources to support the idea dental deformity is linked to diet, upon what do you base your assertions that Japanese have “such bad teeth,” and that Germans and Koreans have “much better teeth than the Japanese” – anything other than your own anecdotal evidence?
    None of your linked sources refer specifically to the issue of dental deformity among the Japanese population, nor support a notion of greater frequency than in other countries. If the problem is indeed worse among Japanese – and it may be – it should be borne out by epidemiological studies.
    Could the prevalence of crowded teeth that you perceive be linked not simply to dietary reasons, but to a lower uptake of corrective procedures? This strikes me as one of the first questions one would ask in investigating why Japanese have “such bad teeth,” if indeed they do.
    Why would so many cases of tooth crowding that, in your opinion, pose a threat to health go untreated in a country supposedly among the best in the world in terms of access to medical treatment? Is it because the country has a different (actual medical) definition of problematic dentition? Or are there issues related to the costs of orthodontic treatment?
    It may have been worthwhile to speak to people who actually work in the fields of dentistry or public health in the country – they could probably contribute something more substantial than the foreign press’ superficial, Orientalist analysis of the over-reported yaeba ‘craze.’
    Finally, the fact that the work of Weston Price is not “common knowledge” might be because his theories, including those linking nutrition to dental deformity, are fairly controversial and far from widely accepted among the scientific establishment. Holistic dentistry, of which he was a pioneer, is considered by practitioners of mainstream medicine to be, at best, on the fringes, and at worst, downright quackery.

    • You bring up some very good points and are spot on with a couple of things.
      Firstly, you are right that I have little evidence for asserting that Japanese people have particularly bad teeth. It’s something that many foreigners here notice and talk about, but that is still, nonetheless, anecdotal.

      You are also correct that it is down to a lower uptake of corrective procedures (you’ll notice that I did say in the post that British teeth had improved because of extractions and orthodontics. My English dentist told me Japanese people are known to have bad teeth and the main reason is not extracting). It is possible that without orthodontics American and European mouths would look more like Japanese ones. However, the real question is, why are orthodontics needed at all? Why don’t we all have the wide jaws and straight, well-spaced teeth of the traditional cultures Price explored– and why are some people still born like that? Perhaps I should have framed it differently: why do a lot of people the world over have bad teeth, and what specific parts of the Japanese diet might cause imperfect teeth?

      It’s a hugely overlooked issue, and it seems odd to me that while it’s accepted that a population’s skulls shrink when they switch from a hunter-gatherer diet to an agricultural one (see this article which mentions the “degeneration of dentofacial development over the last 5000 years” (see, and it’s also accepted that nutrition plays a part in tooth formation ((, but no one bothers to link the two together or look further into how nutrition can shape the size of your jaw. If it’s accepted that bone density, size formation etc is affected by vitamins and minerals, why don’t people recognise that teeth are too?
      This ( is a good article about how mainstream dentistry simply ignores nutrition and doesn’t link the dots.

      Instead, the absurd argument that people used to have larger jaws because they chewed harder things is accepted. This makes no sense. Why are children born with narrow or wide jaws when they don’t even chew for the first couple of years? Hunter gatherers may eat harder food but correlation isn’t causation.

      Decay is a separate issue to jaw size and teeth formation, but they are linked in that poorly formed teeth (eg weak dentine and enamel) are more vulnerable to decay. There is evidence ( that even the Jomon hunter-gatherers had much more dental decay than other hunter-gatherer populations, which the author blames on their high consumption of nuts (that phytic acid again). This WHO report ( see pg 204) shows that 12 year old Japanese children have roughly double the rate of decayed, missing or filled teeth than American or British children. This study ( suggests rice is cariogenic and to blame for higher rates of dental decay in the rice-eating Yayoi farmers compared to Jomon hunter-gatherers.

      As for Weston A Price being controversial, I’ve never seen his theories on diet properly refuted. You might have seen this article on Quackwatch ( which makes the same mistake as you in doubting Price because he pioneered holistic dentistry, which has admittedly spawned a lot of odd ideas–but he isn’t to blame for that. As for the other claims, the Weston A Price foundation posted a nice rebuttal (scroll down to find the bit about Stephen Barrett, the author at Quackwatch):

  10. I thought that dental and jaw structures changed a lot during the advent of agriculture and people bred grains which were smaller and easier to chew. Neolithic people had much larger teeth and jaws I thought in order to chew wild grains.

    It is true that vegans lack certain important vitamins in their diet but usually it is recommended that one eat fish or shellfish rather than meat and dairy products to make up for these. Whilst such products may be good for your teeth they are also high in cholesterol and saturated fats which of course mean lots of heart disease and bowel cancer. The fibrous husk of pulses and whole grains helps provide digestive fibre which may be bad for the teeth but is certainly good for the bowels.

    I read somewhere that tooth decay was almost unheard before the agriculture of sugar cane. Sugar is by far and away the biggest determinant on tooth decay no?

    Personally I eat a fairly varied diet including diary (but never milk) but almost no sugary foods. I dont brush my teeth often as frankly i dont need to. But if I eat a bag of sweets I immediately get the fur on my teeth. Its the sugar.

    I have a theory that food today may be substantially less nutritious and tasty than the past. Food could have been becoming less tasty for decades and who would know? Its like watching someone you see every day age little by little. The only empirical evidence I have for this is the varying nutritonal content between things like farmed and wild salmon. Farmed salmon for instance have a diet heavy in soy proteins rather than fish meaning lower omega 3 content. Perhaps it is the freedom of wild animals that imbues them with nutritional value. The difference between free range and battery eggs is a case in point. Battery eggs have these weak yellow yolks whereas good free range ones are a deep orange.

    • Ah, saturated fat causing heart disease and bowel cancer. That’s the next sacred cow I plan to attack. (As a teaser, just note that those eating a lot of fatty meat as part of a traditional diet, such as Inuits or the Maasai, have virtually no incidences of either disease. The saturated fat hypothesis is just that: a hypothesis).

      I think you’re absolutely right about food being less nutritious than it used to be. A lot of that has to do with soil depletion, as well as an increase in battery-farmed chickens and caged animals as opposed to free-range. I only ever buy free range eggs and choose not to eat butter really because I can’t get pastured (eg Kerry Gold or Anchor) in Japan; it’s all produced by cows kept inside and fed grains, it seems.

      And yes, sugar is a big part of decay, but decayed teeth have been found on skeletons from well before the proliferation of sugar cane. Egyptian archaelogical remains are notable for their poor teeth, apparently (it’s the grains…!). One important point is that even though sugar and carbohydrates cause cavities, poorly formed teeth formation are more vulnerable to them (see and (

      Two people eating the exactly same diet might have very different rates of cavities for that reason.

      However, the main thing I was getting at in the article was jaw size leading to cramped teeth, not incidence of cavities… and how that jaw size and bone structure is all about nutrition.

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