Tag Archives: jawbone

Child at DentistThe science is clear: processed foods are detrimental to our healthNow, new article in the April 2020 issue of Scientific American suggests that processed foods may undermine our health in ways we may not have previously considered, particularly our oral health.(1) 

 Teenagers and early adults regularly visit the dentist for removal of their third molars—often referred to as wisdom teethBefore this rite of passage, teens and smaller children undergo regular dental visits to fill cavities, remove calculus (tartar,) and, at a minimum, endure a thorough cleaning and polishing. 

Paleontologist and dental anthropologist Peter Ungar of the University of Arkansas says we have lost our way when it comes to dental hygiene and health. 

“Most other vertebrate creatures do not have the same dental problems that we do,” Ungar saysThey rarely have crooked teeth or cavities. Our fossil forebears did not have impacted wisdom teeth, and few appear to have gum disease.” 

Dr. Ungar attributes these maladies to the softer and more sugary foods that we eat almost from birth. Strained peas and apple sauce are poor substitutes for our ancestral diets. Instead, he argues, eating foods that are much less processed cause our jaws and teeth to grow strong, straight, and align properlyto an extent that allows enough space for all 32 of our teeth. Mechanical stress of our growing jaws is key to oral health. 

He also argues that the move away from ancestral diets has led to tooth decay—primarily exacerbated by high sugar content in processed foods, and the subsequent shift in the mouth’s bacterial biome. His view is supported by the work of Dr. Loren Cordain (2),(3) and others associated with The Paleo Diet®.(4)   

For example, Cordain notes, and Ungar supports the observation, that across the animal kingdom, dental problems are not the norm. Humans that pre-date terrestrial agriculture show few signs of dental problems, as is the case with small, isolated human populations today that retain hunting and gathering for food, with no access to westernized foods. 

More recently, the biggest jump in problems occurred during the Industrial Revolution, when access to highly refined foods and sucrose became the norm. Soft, sugary foods tipped the balance of oral health to disaster.

Tooth enamel is one of the hardest natural substances. Enamel is underlain by a tough but relatively flexible layer of dentin. Ungar emphasizes that we emerge at birth genetically preprogrammed to mechanically stress our teeth and jaws rather forcefully. Minimally processed foods that require vigorous chewing allow this natural process of oral stress to occur, much to a person’s oral well-being.

Ungar cited work by Robert Corruccini of Southern Illinois UniversityCorruccini, in a conversation with one of his students from nearby rural Kentucky, was surprised to learn that senior citizens in the student’s community had remarkably high oral health. A follow-up study by Corruccini showed the seniors had better bites than their younger children and grandchildren. The difference? Lifelong experience with lightly processed, hard-to-chew foods. 

The moral here is clear. Dental health professionals need to incorporate an evolutionary perspective in their overall strategies for oral health. 



  1. Ungar, P.S.  2020. The trouble with teeth. Scientific American 322(4):45-49. 
  2. Cordain L., Eaton S.B., Sebastian A., Mann N.Lindeberg S., Watkins B.A., et al. 2005. Origin and evolution of Western diet: health implications for the 21st century.  American Journal of Clinical Nutrition 81:341–54.  https://academic.oup.com/ajcn/article/81/2/341/4607411 
  3. Cordain, L.  2011. The paleo diet: lose weight and get healthy by eating the foods you were designed to eat. John Wiley and Sons, New York. 266pp. 
  4. Vuolo, S.  2016. Tooth decay and the paleo child. The Paleo Diet Newsletter.  https://thepaleodiet.com/tooth-decay-and-the-paleo-child/ 

Why Is My Jaw Shrinking? The Dental Problems of a Western Diet

For 200,000 years before grain agriculture, the human jaw and the size of teeth were basically static. However, for the last 10,000 years or so, which coincides with the advent of agricultural farming, the width, length, and shape of the human jaw have been decreasing and changing slowly while the size of the teeth have changed very little.

So, what is going on?

Although genetics play a role, our environment has been the dominant contributor influencing poor jaw development. There appear to be three major external factors that are affecting the size and shape of our jaws. Two are the results of the onset of agricultural farming, and the more recent factor is the result of how babies are fed. They are:

  • Decrease in Nutrient-Dense Foods
  • Increase in Soft Foods
  • Decrease in Breastfeeding


Nutrient-rich food sources declined after agricultural farming provided a significantly increasing proportion of processed foods to our diets. The lack of necessary nutrients in the acellular carbohydrates of these grain and sugar products compromised bone metabolism.1, 2

Dr. Weston A. Price, a dentist, published Nutrition and Physical Degeneration in 1939. Price documented numerous observational examples of primitive peoples who had healthy dentitions and others who had various dental problems including gum disease, tooth decay, and poor jaw development. He identified that those with healthy dentitions generally ate nutrient-dense foods, and those with unhealthy dental conditions regularly consumed diets high in flour, sugar, processed vegetable fats and processed foods. Price implicated a lack of both fat-soluble vitamins and trace minerals to be the most important deficiencies causing dental problems.

Since then, there have been numerous observations among hunter-gatherer societies who had relatively healthy bodies with little or no chronic disease. Those hunter-gatherers who continued to eat their natural diets had healthy dentitions and those who left their traditional diets and began to eat a “western diet” developed dental problems and jaw shrinking and had offspring with increased dental abnormalities.3


Soft food sources, which reduced the physical stimuli on the jawbones and muscles of the jaw, increased after agricultural farming.

Processed grains and starchy foods provide a soft diet. Recent research has demonstrated that softer diets created less mechanical stimuli to the muscles and bones of the jaw resulting in a slow decrease in the density and the dimensions of the jaw over the course of time. Jaws didn’t need to be as strong or as large if the foods were less hard and less strenuous to chew. Rather than happening over an evolutionary time-scale, the change to the mandible was happening on an individual level as each child was growing up.4


Breastfeeding decreased after bottle-feeding became commercialized in the 1800s, which had a dramatic effect on the development of the jaw.5

Evidence suggests early humans breastfed until about three or four years of age. In the United States in 2011, 79% of newborn infants started to breastfeed. However, of infants born in 2011, 49% were breastfeeding at 6 months and only 27% were still breastfeeding at 12 months.6

Breastfeeding provides optimal oral mechanical stimulation for the jaw’s normal development. When infants breast-feed, they form a deep latch onto the breast. They open wide and take in enough breast so that the breast is pressing up against their palate. Babies do not merely “suck” the milk out, but instead they use their tongue in a U-shaped curve on the breast. In a wave-like motion they “milk” the breast to receive its nourishment. Two developmental actions take place: (1) a rhythmic action of the tongue “milking” the breast, which presses on the palate, and (2) the subsequent action of swallowing. Both actions play a critical role in proper stimulation and development of the dental arches, palate, jaw and muscles. As the baby grows, the breast continues to conform to the baby’s mouth.7

When bottle-feeding replaces breastfeeding, the unnatural nipple on a bottle does not fill or conform to the baby’s palate, and therefore does not stimulate any widening of the palate to ensure room for future teeth. Also greater suction forces are required during bottle-feeding. This forceful action causes the cheeks to draw in, putting pressure on the gums and alveolar bone, affecting the position of the teeth. As the baby grows, the bottle nipple remains constant and does not adapt to the developing mouth of a growing child, further compromising normal bone and muscle development


These are observational studies, and there is controversy about the significance of the factors I have discussed. But, eating nutrient-dense foods that represent the nutrition of our primal ancestors will enhance our body’s ability to do what it was designed to do. In addition, we should include raw foods as well as crunchy foods like nuts and seeds to stimulate and exercise the muscles and bones of the jaw. We need to chew our food thoroughly. Mothers should breast feed their children for as long as prudent. Our health and our children’s health are dependent on these primal and natural lifestyles.

Dr. Alvin DanenbergDr. Danenberg is a periodontist in South Carolina who has been in practice for 40 years. Within the last 4 years, he has included Laser Periodontal Therapy as his primary treatment for periodontal disease. The procedure is called “Laser Assisted New Attachment Procedure” or “LANAP”. The last two years he has incorporated a lifestyle program for all his periodontal patients including an ancestral diet to enhance their overall body’s health and function. In July of this year he was awarded the designation, “Certified Functional Medicine Practitioner.” For more information,  please visit www.DrDanenberg.com.



[1] Tucker KL (2009) Osteoporosis prevention and nutrition. Curr Osteoporos Rep 7:111–117

[2] Spreadbury I. (2013). Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity. Diabetes Metab. Syndr. Obes. 5, 175–189

[3] Am J Clin Nutr March 2000 vol. 71 no. 3 665-667

[4] Sardi M, Novellino PS, Pucciarelli HM. 2006. Craniofacial morphology in the Argentine Center-West: consequences of the transition to food production. Am J Phys Anthropol 130: 333–343.

[5] Stevens EE, Patrick TE, Pickler R. A history of infant feeding. J Perinat Educ. 2009;18:32–39.

[6] CDC. Breastfeeding Report Card. Rep. Atlanta: Center for Disease Control and Prevention, 2014. Print.

[7] Palmer B. The influence of breastfeeding on the development of the oral cavity: a commentary. J Hum Lact 1998; 114:93-98.

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