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With promising headlines like "Blame Your Crooked Teeth on Early Farmers", "For Perfect Teeth, Start Hunting and Gathering", and "Wisdom teeth hurt? Blame your ancient ancestors", it seemed like science may have stumbled upon something that has been asserted by many "fringe" doctors (Weston A. Price) and anthropologists (Jared Diamond) for decades.
It all starts off well, for example, the History.com coverage leads with the following passage...
"(A)nthropologist Noreen von Cramon-Taubadel at the University of Kent in England has conducted a global analysis, comparing skull and jaw shapes of 11 populations living in various parts of the world—five with hunter-gather subsistence strategies and six with agriculture-based ways of life. She found that skull morphology has more to do with genetics than with food choices, finding little correlation among groups with similar habits.
As for the anatomy of the lower jaw, on the other hand, Cramon-Taubadel observed a strong dietary influence. In hunter-gatherer populations, people have long, narrow jawbones that give teeth plenty of breathing room. Members of agricultural societies, by contrast, tend to have shorter, smaller jaws that have trouble accommodating humans’ relatively large choppers—leading, it appears, to impacted wisdom teeth, overbites, crowding and other woes that land many of us in the dentist’s chair on an all-too-regular basis."
At this point, you might expect the study author (and the subsequent "journalists") to discuss how a shift from fat, protein and nutrient rich, hunter-gatherer diets, based on numerous plants, insects, small and large animals, fruits, and fish to vitamin and mineral deficient, high-carbohydrate, cereal-crop based agriculture resulted in the malformed jaw and crowded teeth.
This is what Jared Diamond discussed in his 1987 article for Discover magazine. In the piece, aptly named "The Worst Mistake in the History of the Human Race", Diamond cites the following research:
"At Dickson Mounds, located near the confluence of the Spoon and Illinois rivers, archaeologists have excavated some 800 skeletons that paint a picture of the health changes that occurred when a hunter-gatherer culture gave way to intensive maize farming around A. D. 1150. Studies by George Armelagos and his colleagues then at the University of Massachusetts show these early farmers paid a price for their new-found livelihood. Compared to the hunter-gatherers who preceded them, the farmers had a nearly 50 per cent increase in enamel defects indicative of malnutrition, a fourfold increase in iron-deficiency anemia (evidenced by a bone condition called porotic hyperostosis), a threefold rise in bone lesions reflecting infectious disease in general, and an increase in degenerative conditions of the spine, probably reflecting a lot of hard physical labor. 'Life expectancy at birth in the pre-agricultural community was bout twenty-six years,' says Armelagos, 'but in the post-agricultural community it was nineteen years. So these episodes of nutritional stress and infectious disease were seriously affecting their ability to survive.'"
All too predictably, however, the "explanation" skirts the issue of nutrient deficiencies (deficiencies which were corrected by some later agricultural societies as noted in the work of Weston A. Price) and instead, focuses on the absurd notion of "masticatory stress". In other words, "soft foods" are to blame. (*face palm*)
In the MSNbc.com coverage of the research, this resulted in the following summary:
"The jawbone differences von Cramon-Taubadel saw between populations depended on diet. Overall, people who lived a hunter-gatherer lifestyle had longer, narrower jawbones. This might be due to how people in agricultural societies more often eat softer foods such as starches and cooked items, while hunter-gatherers on average eat more foods that are raw and unprocessed. The amount of exercise that jaws experience from their lifestyles affects how they grow and develop — longer jaws may do better on diets that contain harder items."
(Warning: Sarcasm Ahead!)
What an interesting notion! I always thought that bones grew stronger (as a factor of increased bone density) when exercised, but apparently they can actually grow longer too! I guess I should have jumped more rope as a child, if only to achieve my dream of playing in the NBA.
The Wired.com coverage even shares this piece of "supporting" evidence:
"von Cramon-Taubadel cites experimental studies showing that animals raised on softer, more processed foods grow smaller jaws than those fed fresh, unprocessed food."
The author then cites the more toothsome "raw" foods eaten by hunter-gatherer (vs the "cooked" foods eaten by agriculturalists) as another factor contributing to the protective mandibular workout.
I find this particularly perplexing, especially after having recently watched the documentary film "Purarambo" (available on Netflix!) In it, the filmmakers visit isolated tribes in the deep jungle of New Guinea. The staple foods include a starchy extract of sable palm pulp (soft), fat rhinoceros beetle grubs (soft), roasted green bananas (soft), and all manner of animals cooked in banana leaves (maybe not "soft", but definitely not raw).
Sadly, the issue of nutrition exerting an epigenetic influence on our physical devleopment is neither discussed nor even hinted at in either von Cramen-Taubadel's paper or any of the subsequent journalistic pieces. Instead, the focus is on the spurious notion of "soft" foods.
It is my hope, however, that this article will leave some people scratching their heads, wondering how the hell chewing on hard things gives you a Hollywood smile. Perhaps, some of these people will then stumble upon this or one of the many other sites dedicated to exploring Evolutionary Nutrition, and realize that they're initial "WTF" was correct.