Scientists have suggested several different theories over the decades as to what causes crooked teeth in humans. When my Dad started medical school in the late 1940′s, he was taught that racial mixing (Italians marrying Irish for example) was the cause of crooked teeth. Malocclusions had just started to reach epidemic proportions in children at that time.
Of course, this theory of racial mixing causing crooked teeth which was incidentally presented as fact to the wide eyed medical students of the time is completely ridiculous and has long since been disproven.
Other theories include thumb sucking and consuming soft foods which are suppositions subscribed to by many orthodontists. The soft food theory suggests that because humans don’t exercise their jaw muscles enough that our jaws have become weak and narrowed over time.
One orthodontist once told me (while I struggled to keep a straight face) that wisdom teeth were being genetically “selected out” of the gene pool because they are no longer needed because of the different foods that humans now eat compared with ancestral societies.
Now comes a variation of the “soft food causes crooked teeth” theory which was recently described in a study published in the online edition of the Proceedings of the National Academy of Sciences.
This new theory states that the move of humans from primarily hunter-gatherers to farmers around 10,000 years ago put us on the inevitable road to the orthodontist’s chair.
To test this hypothesis, Noreen von Cramon-Taubadel, an anthropologist at the University of Kent in the UK, examined the skull and jaw shapes of ancient skeletons housed in museums that originated from Africa, Australia, Europe, and North/South America. Six of the populations lived by farming and five were hunter-gatherers.
A significant correlation existed between how a population obtained its food and the shape of the jaw. Hunter-gatherers had narrower and more jutting lower jaws whereas those of the agriculturalists were shorter and wider.
The shape of the upper jaw and palate also varied somewhat between the farmers and hunter-gatherers.
Von Cramon-Taubadel concludes by suggesting that the transition to farming and an increase in food processing both of which led to consumption of softer foods resulted in a shorter and weaker human jaw. Jaw shortening leads to greater crowding of the teeth.
To lend support to her theory, von Cramon-Taubadel refers to preliminary studies of animals which show that those that are raised on softer more processed foods develop smaller jaws than those raised on fresh, unprocessed diets.
Katerina Harvati, an anthropologist at the University of Tubingen in Germany says that this recent paper by von Cramon-Taubadel is a “well thought out piece of research and an important contribution” to understanding how the way humans live affects their body shape.
She goes on to say, “These findings confirm long-held ideas that the dietary shift to softer foods was an important influence affecting facial and dental morphology.”
The Soft Food Theory Ignores Contradictory Evidence
Strong contradictory evidence to the soft food theory as a reason for crooked teeth is presented in Dr. Weston A. Price’s book Nutrition and Physical Degeneration. How such convincing evidence was completely ignored as part of this supposedly “well thought out piece of research” is rather surprising and I would think, downright embarrassing for the author.
While hunter-gatherers certainly had strong jaws which allowed them to consume hard foods, the strength did not come from greater exercising of the jaw muscles! As suggested by Sally Fallon Morell, President of the Weston A. Price Foundation, such a theory makes the critical mistake of confusing muscle with bone.
A narrowed jaw and palate, for example, can be identified in babies at birth long before they have chewed anything!
Dr. Price also correctly pointed out that when the jaw and palate are narrowed, other parts of the skeleton are correspondingly narrowed as well such as the pelvic opening which causes greater difficulty in childbirth and the chest cavity which crowds the vital organs.
The Swiss farmers studied by Dr. Price subsisted on very soft foods and yet had beautifully broad palates with perfectly straight teeth. Moreover, the South Sea Islanders photographed by Dr. Price with perfectly straight teeth consumed primarily seafood and poi, both soft foods with poi, in particular, a very soft and sticky staple carbohydrate in their diet.
The Truth About Crooked Teeth
Von Cramon-Taubadel did get one aspect of her paper correct. The rise of food processing did indeed contribute to the modern epidemic of crooked teeth, but not because such foods are softer than unprocessed foods.
Rather, processed and industrialized foods are devoid of the critical nutrients necessary to produce a broad and sturdy jaw with correspondingly straight teeth.
Dr. Price’s research compellingly argues that a lack of jaw development and crooked teeth is entirely nutritional in origin such as attempting to build a wide bridge with substandard materials.
Without essential nutrients in the form of minerals and the fat soluble activators A, D, and K2 which were abundant in primitive diets, the jaw and palate cannot form with enough strength to support a broad facial structure. Hence, narrowing of the face and crooked teeth are the result no matter how hard the food that is chewed.
Anthropologists of all people should realize that chewing rocks will not produce a broad jaw and straight (albeit broken) teeth!
Sarah, The Healthy Home Economist