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A Modern World of Endemic Jaw Dysfunction

Summary:
The book Breath by James Nestor is a revelation. It is well worth this third blog post on the book. (The other two are flagged at the bottom of this post.) A fact James Nestor points to is the dramatic change in human skulls—and particularly upper and lower jaws—over the course of the last few centuries. There are plenty of human skulls around from a few hundred years ago as evidence; this fact is not in dispute. Since gene frequencies are unlikely to have changed substantially in such an evolutionarily short time, the leading theory is that softer food is the cause. The introduction of agriculture brought an earlier change in human skull form,

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A Modern World of Endemic Jaw Dysfunction

The book Breath by James Nestor is a revelation. It is well worth this third blog post on the book. (The other two are flagged at the bottom of this post.)

A fact James Nestor points to is the dramatic change in human skulls—and particularly upper and lower jaws—over the course of the last few centuries. There are plenty of human skulls around from a few hundred years ago as evidence; this fact is not in dispute. Since gene frequencies are unlikely to have changed substantially in such an evolutionarily short time, the leading theory is that softer food is the cause. The introduction of agriculture brought an earlier change in human skull form, but the last few centuries have made it common for people to eat even softer food than earlier on in the agricultural era.

I have argued that evolutionarily, human beings are designed as if on what used to be a safe assumption that human beings would face frequent periods with little to no food. In particular, critical repair and cleanup processes such as autophagy only happen during periods of little to no food. If true, this means that our bodies will malfunction in various ways if we eat all the time and don’t build in periods of time of little to no food (“fasting” from food, but not from water).

Similarly, the process for human jaw development is designed as if on what used to be the safe assumption that we would be eating tough food, then if we eat soft food all the time, our jaws are likely to malfunction. And of course they do. Orthodontists do a lot of business removing and straightening the teeth of people whose jaws are too small for their teeth.

Contrarian orthodontist Mike Mew, following in the footsteps of his father John Mew, argues that going radically toward breathing through the nose as much as possible rather than through the mouth and making a habit of keeping a tongue posture with the tongue at the top of the mouth and pressed toward the back of the mouth can help make up for the baleful effects of soft modern food. Of course, it is also helpful to eat tougher food—food like nonstarchy vegetables with a lot of insoluble fiber.

Radical nose breathing and pulling the tongue up and back go together. You can’t easily breath through your mouth with the tongue in this posture. Indeed, this tongue posture even prevents air from going in the nose and through the back of the mouth. It has to pursue a path through the nasal passages all the way along. In addition to tongue posture, having the traditionally lauded head posture is also important. That coupled with the high-and-back tongue posture requires even more radical nose breathing in order to get air. All of this takes some getting used to. The easiest part is actually doing nose breathing, not mount breathing while asleep: mouth taping will do the trick. (See “James Nestor on How Bad Mouth Breathing Is.”)

Mike Mew has had the most success with kids whose jaw is still growing—say 7 to 9 years old. Starting young like that, he claims kids can often avoid needing orthodontics they otherwise would have needed.

But many who are older are also trying to affect their jaw structure with tongue posture. The hope is that an up-and-back tongue posture will cause the upper jaw to lengthen, which then allows the lower jaw to take more natural somewhat more forward position.

There are now many, many videos on YouTube showing how to do proper tongue posture. John Mew called his approach “orthotropics”: trying to get the jaw to grow in the right way; but online this approach is typically called “mewing” after John and Mike Mew.

There is nothing inherent about orthotropics or “mewing” that limits its potential value to one subgroup of the population. According to the theory, almost all of us have messed-up jaws because of our soft diets. (I myself had substantial orthodontic work done because my jaw was too small for my teeth.) In particular, proper development of the jaw is very important for women as well as men (both for function and for looks). However, somewhat strangely, though I suppose understandably, young men who are vocal about trying (and so far often failing) to get women interested in them dominate the discussion of mewing online. That takes a little getting used to when you look at some of these videos! One way to avoid running into that too much at the beginning is to start with videos by Mike Mew himself. See for example this one:

Not surprisingly, orthotropics is a heresy within orthodontics. But I find it quite credible. To convince me to discount orthotropics, I would want to hear more orthodox orthodontists engage with the evidence of dramatically changing human jaw formation over the last few centuries and give an explanation that doesn’t really on the amount of mechanical action of the jaw influencing jaw growth. Alternatively, orthodox orthodontists could argue that eating tough food would lead to more jaw growth, but that up-and-back tongue posture and mouth-taping (to avoid mouth breathing) at night won’t have much effect on jaw growth.

Note that Mike Mew’s primary claim is about the power of early intervention—in the 7-9 year-old range, and Mike is quite cautious about claiming much for interventions that only begin in adulthood. So showing a relatively small effect from interventions in adulthood, though it would be quite important, is not a disproof of orthotropics.

In evolutionary psychology, there is a claim that we are drawn to youth. But when I combine all of the chronic diseases associated with modernity—including obesity, its associated diseases, and the jaw malformation this post is about—I am starting to think that perhaps even half of what we think of as “aging” is really the gradual progression of these chronic diseases. The visible signs of chronic diseases tend to look unattractive to us. If you can beat most of the chronic diseases modernity has put us in grave danger of, then you are either likely to look what we often think of as “younger”—or you will look more attractive in the manner of dignified age.

But it isn’t all about looks. There is a quickly rising incidence and even more quickly rising recognition of the toll of obstructive sleep apnea. Obesity is a contributing factor to obstructive sleep apnea. Age is a contributing factor to obstructive sleep apnea. But I’ll bet overly small jaws also contribute to obstructive sleep apnea. Personally, I would be glad if working on my tongue posture causes my upper jaw to grow just fast enough (even if it is only a few millimeters) to counterbalance the increasing risk of obstructive sleep apnea from other things that happen as I get older.

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Miles Kimball
Miles Kimball is Professor of Economics and Survey Research at the University of Michigan. Politically, Miles is an independent who grew up in an apolitical family. He holds many strong opinions—open to revision in response to cogent arguments—that do not line up neatly with either the Republican or Democratic Party.

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