How kids get straight teeth


Among a lot of great lectures at the Ancestral Health Symposium, there is one I have been meaning to write about for a long time now. I found it fascinating.

Why do so many Westeners develop crooked teeth? Bad genes is a common explanation. But is it true?

A new problem


According to the dentist and the orthodontist lecturing, today about 95 percent of the population has some form of malocclusion, meaning more or less crooked teeth and/or overbites and such. Many of these problems are corrected using braces while growing.

Amazingly, looking at skeletal remains of our ancestors only 5 percent of them had similar problems. And looking at wild animals we see the same scarcity of similar problems. Lions don’t need braces.

From a “natural” rate of 5 percent, all the way to 95 percent bad bites! What happened?


Something in our modern diet and/or lifestyle makes our jaws grow unappropriately. What? We don’t know for sure.

One speculative answer is an excess of refined carbs. This can increase insulin and IGF-1 to abnormal levels. These are growth factors and when they are too high it can disturb normal growth.

A second possible reason is not eating food that we need to chew hard. Only eating soft (fast) food is not normal for humans, and may stop the teeth and jaws from developing normally.


Another thing that may contribute is substituting formula for breastfeeding!


The foundation for the problem in crooked teeth is that the palate is not wide enough, not big enough for fitting all the teeth in it. Thus the teeth become crowded and crooked (above, left).

Breastfeeding apparently has a widening effect on the palate. At least according to the dentist lecturing. Potentially a lot of breastfeeding could thus give better chances for straight teeth (above, right).


Listening to this lecture a few months ago made me very anxious to give my new baby girl the best start in life, even when it comes to her teeth.

I’m happy to report that Klara is breastfeeding as much as she wants. And her palate? Looks very wide to me.

So far so good.

What do you think?

What do you think about the theories above?


Here is the lecture (unfortunately the quality of the recording is god-awful)

Ancestral health, obesity and smurfs


  1. Margaretrc
    Interesting. I did breastfeed both my children and one of them ended up wearing braces--my daughter, who weaned herself after 10 months. She also sucked her thumb, so that may have had something to do with it, too. My son, who was breast fed for more like 18 months, maybe longer--don't remember, it was a long time ago--and had a natural shaped pacifier, did not. n=2, though. It's very possible breast feeding or not has something to do with it, but it can't be the whole story. I think a lot more than 5% of the children in this country are breast fed. I'm guessing generations of eating a lot of refined grains and sugar may have contributed as well. One thing's for certain--it is something in the environment (and as a result epigenetic, perhaps) and not the genes themselves. We haven't had time to evolve that much in such a (relatively) short time.
  2. Judi O
    I breastfed both of my boys - the second one never got any formula at all - but they both had small palates and teeth that required braces. I have read some material from Weston A. Price with the suggestion that refined carbs can be a contributing factor. We didn't eat a lot of junk food and I cooked most meals from scratch, but I know so much more now about nutrition. What I wouldn't give for a do-over!!!
  3. Tooticky
    For anyone who is interested in nutrition and dental issues I can recommend a book by Weston Price "Nutrition and Physical Degeneration: A Comparison of Primitive and Modern Diets and Their Effects". It is written around 1930s (if my memory serves me correct) and therefore the language he uses is occasionally not politically correct in modern terms. However, if you can put up with that without getting upset, you'll find interesting information how a diet affects health and especially tooth development. I was astonished to find out how changes can happen in one generation alone. Although, the book concentrates so much on the dental issues that it was a quite tiresome read for myself as I don't have such a passion for teeth...

    Interestingly, if you read entry about Weston Price in Wikipedia ( looks like he got heavily criticized by some scientist in his time... so I guess there is nothing new under the Sun... ;)

    Doc, you wife is doing a sterling job in breastfeeding your little daughter, glad to hear everything is going well. Another great book is Garbrielle Palmer's book "The Politics of Breastfeeding: When Breasts are Bad for Business". I was reading that myself while b/feeding my little one, and it really opened my eyes how (food) industry is maneuvering people's behavior... and mostly for their benefit not ours. That book was the wake-up call I needed to start looking for information myself and not believing everything I read from the papers.

    Lastly, thanks for the great blog :)

  4. Janknitz
    Breastfeeding or lack thereof may be a factor, but keep in mind:

    Not everybody CAN breastfeed--think of adoptive parents, and birth moms with medical issues that interfere with milk supply.

    I had some medical issues that prevented successful breastfeeding (I tried very hard and was devastated both times that I could not breastfeed). So both my children were bottlefed. One child got the broad palate and perfect alignment of her father, one child inherited my very narrow, highly arched palate.

  5. Shortages of the fat soluble vitamins A, D3, K2 and folic acid are IMO probably the reason.
    I don't think most people eat liver regularly nor do they consume sufficient traditional fats and making bone marrow stock for soups/stews isn't a part of most households weekly cooking neither do we spend sufficient time soaking up the sunshine outdoors wearing little if any clothing.
    Hollis and Wagner have done the work showing how much vitamin D3 daily is required at latitude 32n to ensure human milk is a vit d3 replete food for human babies BUT WHO TAKES ANY NOTICE?
    I also think
    The Natural Age of Weaning is probably
    older/longer than many people are willing/able to provide.
  6. Also, keep in mind that infant mortality was much higher in ancient times--it's possible that infants with narrow palates and thus crooked teeth were substantially less likely to survive to adulthood and leave remains with teeth that could be analyzed. When all you have is a correlation, it's possible B causes A instead of A causing B.

    I was breastfed exclusively and I had to wear braces for 4 years. My palate was plenty wide, it was just that my teeth were ENORMOUS. My brothers had much fewer problems even though they were alternately breast/bottle fed. They have smaller teeth than I do.

  7. All of the above. Genetics, epigenetics (I'm a 3rd generation bottle-fed baby from high latitudes and low altitudes) and the physical pressure and oral positioning of breastfeeding all contribute to arch development. I recently read a PPT somewhere online that talked about the constant pressure of the tongue as a formative force in the skull; it stands to reason that the extensive and intensive actions required in breastfeeding would have an effect on the malleable infant mouth.
    Besides which, in affluent cultures breastfeeding is correlated with maternal education, which is correlated with nutrition.
  8. nil
    I was breastfed for a long time, had no pacifier, didn't suck my thumb, was born before the age of fast food, but: My mother ate a standard diet.
    I had four teeth removed and still my palate isn't really big enough.

    I think the Universal Standard Diet is probably to blame, and not just refined carbs, but also dairy.
    (When you mentioned IGF-1, I immediately thought of Pedro Bastos' AHS talk.)

    I hope you're not biased toward blaming carbs and leaving dairy in the dark :)

  9. aron
    I get so annoyed when people cant use pictures and present things in a good way. What kind of visual blindfool did this poster?
  10. Em J
    I too highly recommend the Western A. Price book: "Nutrition and Physical Degeneration: A Comparison of Primitive and Modern Diets and Their Effects".

    It's a real eye opener - he was a dentist who went around different indigenous populations throughout the world (back in the 1930's), to study rates of dental carries (cavities) and "deformities" as he called them such as overbites, overcrowding of the teeth etc.

    He would take measurements of children and adults in their indigenous settings and then also take measurements from the people that had left their tribes to become more westernized (so were eating less whole foods and more refined carbs and canned foods).

    His findings were very enlightening!

    @ nil - just wondering what the problem with dairy is, and why you think this would be a contributing factor?

  11. Jeff R
    There was an article in Wired recently that discussed a paper about the change in mandible size for humans after the development of agriculture. They attempted to explain it though the amount of stress the jaw receives now compared to hunter-gatherer days. But it's really interesting to compare that viewpoint to Dr Price's findings. On the whole, I think Dr. Price's explanations explain it much more satisfactorily. (The article is at .... assuming links are allowed). The actual paper is linked from the Wired article if anyone is really interested - although you'll need access from a research institution to get it without paying for a copy.
  12. This is very interesting and i really think Weston A Price did some great observations. He claimed that eating refined carbohydrates for 1-2 generations almost certainly gave croked teeth and misshaped jaws.
    I know that my grandparents and my parents and their siblings had very little refined carbohydrates in their diet. My grandparents om my fathers side has about 125 decendants, and i cant recall any of them having bracers. Me and my siblings have never pulled teeths or used bracers and we all have somewhat broad faces with room for every teeth.
    I think its possible to say that If youre teeth are to crowded, its your parents and grandparents diet that caused it.
  13. Always an honer to see your self being talked about and even my slides and words repeated.My view is that the faces of modern man are longer due to weak muscles and a n open mouth posture. The longer the face the narrower and the shorter, hence crowded teeth. The main cause is the lack of tough masticatory effort (from a soft high calorie modern diet, chips spend nearly half the day eating -Wrangham 1977), the second cause is the lowering of the tongue to maintain an airway during periods of blocked noses, which becomes a habit, and the final one is early weaning. Obviously breast feeding is part of the early weaning but it is not a direct effect. Kevin Boyd, my co-lecturer feels that this is more important and is supporting and following research underway in Oz on this.

    Jennifer, your early death argument has been made many times before however we do find infant skulls (as indeed infant mortality was high) but you would expect to fine a spread of different types of malocclusion if this was so. However you don't, they ALL (less 5% disease, syndrome and trauma) have perfect sets of teeth. For which you must ask what is perfect since today most people have a space between upper tooth number 6 (left to right) of about 30-35mm, it was over 50 for most ancient humans!!! Are we now normal?

    Please feel free to make comments on Y Crooked Teeth, my facebook page. I am campaigning for a debate on the cause of crooked teeth, the truth must out and it aint going to happen without some pressure,

    Best wishes


  14. kimberly
    I breastfed both my kids for a year, exclusively for the first 6 months. They both needed palate expanders.

    I think I can confidently pinpoint my following the food pyramid in our diet as the culprit here. I kept us all on a fairly low-fat diet and used meat primarily as a condiment with grain-based meals. The boys don't drink much in the way of cow's milk, and I only kept fat-free in the house anyway. Fat free everything, pretty much.

    I have since learned better, and have radically changed our diets. I personally have essentially perfect teeth. I grew up the 70's in an area where my parents purchased a whole pastured cow from a farmer friend every year, and grew most of our vegetables. So I grew with high animal fats with very low incidence of pesticide or hormone use.

    My parents thought my low-fat thing was crazy, though not because of the kids, just in general. Once again, they were right.

  15. Heather
    All I know is that I did not breastfeed my son and he has perfect teeth. Breastfed my daughter for two years. She has very crooked teeth and will need braces. I think breastfeeding is one of the very best things you can do for your child. There are so many benefits to to it but I am not convinced that perfect teeth is one of them.
  16. Diane
    I was breastfed and my teeth were crooked and I needed braces. I watched the presentation of Dr. Mew online. As a child I could not breathe through my nose. I had a lot of allergies: yeast, mold (i.e. bread and cheese), dogs, cats, rabbits, feathers. I sucked my thumb. I had a tonsillectomy and adenoidectomy when I was 7 but nevertheless I have never been able to breathe with my mouth closed at all times. At least not if I'm exerting myself. I can keep my mouth closed if I'm just sitting or walking. As an adult, I believe my face is very long and my teeth have reverted to crooked in a couple of places. Dr. Mew's theory is interesting and I am curious if adults can make changes like children can, if there's an age cut-off.
  17. Martin Levac
    A child grows because of growth hormone. The more GH , the more growth. Bones grow longer and bigger in response to GH. Teeth do not. When insulin rises, GH drops. If our diet keeps insulin high chronically, it also keeps GH chronically low. Just like braces will apply a small physical pressure over many years to change the shape of the jaw, hormones will do the same thing at the cellular level.

    Additionally, insulin itself will cause other changes such as increased fat tissue mass. So we'll end up shorter and fatter with crooked teeth.

    This is how I see it. It makes sense to me.

  18. Dr. Andreas Eenfeldt, MD Team Diet Doctor
    I'm not sure about "shorter" because we've all been getting about an inch taller on average in the last decades.
  19. Martin Levac
    Andreas, how do you explain this recent increase in average height? Our diet has gotten worse, so that's not it. We do take more supplements, more medicine, and more hormone therapy.

    Anyway, I doubt that we have really gotten taller. We're getting more and more osteoporosis. This affects the spine, which makes us shorter as we grow older. Also, our average BMI has increased, which suggests that we've been getting fatter, or shorter, or both.

  20. Dr. Andreas Eenfeldt, MD Team Diet Doctor
    I'd say the food we eat is too anabolic, too growth stimulating (via insulin and IGF-1). It's making us grow. Kid's grow taller, adults grow fatter, older people grow cancer.
  21. Martin Levac
    If our food was more anabolic, then how do we explain the previous drop in average height once we adopted a high carb diet about 10,000 years ago with the advent of agriculture?
  22. Dr. Andreas Eenfeldt, MD Team Diet Doctor
    Those grains are not as refined and they did not have refined sugar at all, so it's not quite the same thing.

    There may also have been more frequent episodes of starvation, bad harvests etc. back then.

  23. Martin Levac
    If it's about abundance of food, we have that right now and we're still not as tall so that's not it. Monkey experiments of caloric restriction tell us less food is actually good for the monkeys. But then those experiments were done with monkey chow, or what we call a high carb refined highly processed diet. If it's about the grains themselves, we eat more grains today so that's not it either. Even if the grains were less refined, they still increased the carb content of our diet making it more anabolic.

    No, we are not growing taller today because our diet is more anabolic. Instead, we are growing taller today because we do things that counter the catabolic effects of our diet.

  24. What matters is not the number of calories we consume but the uptake of those calories and the ability of our mitochondria to use those calories. We forget the human gastrointestinal tract includes a whole host of bacteria, and those bacteria metabolize some of the calories we consume for their own benefit.
    Why cooking counts Study finds an increase in energy from meat, suggesting key role in evolution
    similarly we forget the impact of mitochondrial dysfunction and the way our exposure to bright light during the day, subdued light at night and total darkness while we are asleep affects melatonin secretion. Most lab rats/mice suffer disruption of their natural circadian rhythm as do most modern humans. A power cut yesterday afternoon that lasted through the night brought home to me that using FLUX is not the same as using only candles during the evening and the total absence of even low level of street lighting also made a difference to sleep quality and duration.

    Not only were the diets of our early ancestors less inflammatory but also their lifestyles were in tune with natural circadian rhythm which would impact both on the nature of their gut bacteria and Circadian rhythms, sleep, and metabolism In the same way we are ignoring the role of bright sunlight exposure on vitamin D and chronobiology we also forget the role of melatonin secretion in protection mitochondrial function. There is 400x the secretion of melatonin in the digestive system than from the pineal gland but it's role is totally ignored by most nutrition researcher & bloggers.

  25. Dear All

    As my co-presenter Mike Mew stated earlier, great to see that our 2011 AHS lecture has generated such chatter! Just to clarify one major point, the term "breastfeeding" for the purpose of the talk was clearly defined as "Ancestral-Type" Breastfeeding (A-TB...i.e., 'at-will' exclusive suckling for at least 6-8 months and continued suckling during weaning into at least the 3rd year of did our paleo/pre-paleo ancestors, and as do extant H-G foragers....references upon request)..); A-TB is only one of two key component of an "ancestral-type" Infant and Early Childhood Feeding (IECF) regimen . The other key component to the "ancestral-type" IECF regimen is the gradual weaning period... again, into at least the 3rd year of life and to only firm-textured/fibrous and minimally-processed Paleo-type complementary foods. Although not at all easy in our Westernized society, if an ancestral (paleo)-type IECF regimen can be adhered to, and also followed up by a committment to eating unprocessed and firm-textured paleo-type foods, according to my hypothesis, most would reach adolescence/young adulthood as good nose-breathers with fairly straight teeth, well-postured tongues and well-formed jaws....and attractive forward faces. This is the foundation for the hypothesis that I will be testing on wild (bred/fed) vs. captive (bre/fed) chimpanzee skulls in MM's "Oz" (i.e., the Field Museum of Natural History in ChicagOZ)...and will be applying for NSF grant support...wish me luck please!

    Merry Christmas

  26. moreporkplease
    "I'm not sure about "shorter" because we've all been getting about an inch taller on average in the last decades"

    This is interesting, Doc, as we see the reverse in the USA. Americans appear to be actively shrinking in size, and have done so mostly over the last 30 years apparently:

    "New research shows that Americans are coming up short, but not in terms of money or lifestyle. Our growing problem is with our height.

    The study, conducted by the University of Munich and Princeton University, found that the United States had the shortest population in the industrialized world, and the reason may have to do with the way people live.

    America's first president, George Washington, stood a commanding 6-foot-2. In Washington's day, our country's residents were the tallest in the world.

    "It's well known that the Americans held the title for 200 years," said University of Munich professor John Komlos. "Ever since the colonial times, the Americans were the tallest."
    In Denmark, men average 6 feet in height, a couple of inches taller than the [now] American male average of 5-foot-10.

    Overeating can cause kids to produce too many growth hormones too early, which halts growth at a younger age. "

    And what are Americans overeating? Refined carbs & sugar.

  27. Rea
    I am the middle child between 2 siblings. The oldest one was breastfed for almost a year. I was breastfed for half that time and my younger sibling was breastfed for almost 2 months. Surprisingly, the youngest one has amazingly straight teeth (and also no cavities) and me and the oldest had to wear braces.
  28. natalie
    Excuse but my child as given no breast, and her teeth are too up ell only 2 of them but they are ay too up. Now she needs braces and she doesnt want them. How could her teeth get straighted without braces?

    Please give me an answer at or here.
    Thank you,
    Natalie Gomez

  29. jenny
    Breastfeeding has NOTHING to do with this all of my brothers including me were breastfed and only 2 of us had to get braces... out of 5 children.. if it had something to do we would all have perfect teeth
  30. Kevin Boyd
    If maybe still interested, please consider watching my most recent presentation ("Sleep Apnea, Attention Deficit Disorder and Small Jaws: Not Likely Things of the Past") on this topic at the 2013 AHS conference held in Atlanta last week as it will clear up some of the confusion generated by my 2011 talk; and new research was presented on how modern infant feeding, pediatric sleep apnea and malocclusion in early childhood might each/all be putting children at risk for ADD/ADHD. Again, my hypothesis argues that a Paleo-type 'infant and early childhood feeding' (IECF) regime, of which breastfeeding is only one, of 3, main components (the others are: 'weaning' to firm/minimally-processed solid foods for a period of 2-3 years, followed by 'lifetime commitment' to Paleo-eating AND Paleo-breathing through the nose, especially at night, with the lips closed and the tongue pressed against the roof of the mouth) was/is conducive to establishing the foundation for wide/forward adolescent/adult jaws that will in turn accommodate an upward/forwardly-positioned tongue and a full complement of 32 well-aligned teeth (i.e., freedom from skeletal and/or dental malocclusion). If anyone has specific questions please feel free to email me directly (
  31. Ted Hutchinson
    AHS13 - Sleep Apnea, ADD, and Small Jaws - Kevin Boyd BOOTLEG audio version only
    I expect a better officIal sound/slide version will be posted soon but in the meantime this may be helpful.
  32. Jenny
    Hi, it's not that breastfeeding widens the palate, it's that artificial feeding, pacifier/dummy use and thumb sucking narrow the palate. Sucking a thumb or artificial nipple (bottle test or pacifier/dummy) use different muscles to those used for breastfeeding. The use of these different muscles exerts unnatural forces on the soft still -growing palate and facial bones, resulting in dental malocclusion and narrowed airways. So pacifier/dummy/thumb sucking can still impact on facial bone development even if baby is otherwise 100% breastfed. (See Dr Brian Palmers research on breastfeeding and dental development )

    As for 'not everyone can breastfeed, don't make the mothers feel guilty' lobby. According to Norwegian figures 98% of women are able to breastfeed, with the right help and support. There are factors which interfere with breastfeeding, maternal/infant separation and illness, some medications (although virtually all are safe to take whilst breastfeeding, if you do the research via Hales or The BNF) and even adoptive mothers can breastfeed, again, if they have the right info, help and support. Only 2% of women actually fail to lactate, the high numbers of mothers who don't breastfeed are mainly due to bad advice, poor support and inaccurate and inadequate information.

  33. Corrie
    I was bottle fed from day one and have all 32 teeth, perfectly aligned and no cavities... I'd say it has more to do with genetics?
    Reply: #34
  34. erdoke
    I wouldn't say so. If you read Dr. Weston Price's book about dental abnormalities all over the world before the 2nd world war, it seems that most, if not all, are caused by diet. I believe it is mainly due to deficiencies in fat soluble vitamins and/or calcium (+Mg). It cannot be excluded that one might get enough sunshine/vitamin D, calcium and vitamin K2 solely through bottle feeding and then via a kind of modern diet. Genetics cannot compensate for the lack of fat soluble vitamins in the diet and/or lack of sunshine.
  35. Lisa
    I was formula fed and have naturally straight teeth. Never had braces or a cavity.
  36. Nkuubi charles
    I think fomula feeding kids and giving them plenty of fruits such as carrot, water melon and sugar canes for a hard bite can greatly bring about straight teeth.

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