Paleo Diet pH: Does It Matter? – Part III

Here are a few more studies that lead me to believe that even precontact Eskimos had an early onset and accelerated rate of bone mineral loss with age that we can most easily explain as an effect of their diet composition.

Type I and Type II Resorption Cavities

In 1979, Richman, Ortner, and Schulter-Ellis studied differences in intracortical bone remodeling in three aboriginal American populations, Eskimos, Arikara, and Pueblo.[1] Specifically, they studied the occurrence of two different types of resorption/remodeling cavities in the bones.

 

Image source:  Wikipedia

In normal Type I remodeling the resorption cavity (resulting from the breakdown of mineralized bone) courses lengthwise through the mineralized sections (lamellae), surrounded by osteons (an osteon consists of a haversian canal surrounded by lamellae).

In Type II remodeling the cavity appears as a small dilation of the haversian canal of an osteon. The haversian canal contains the blood vessels servicing the osteocytes. It appears that Type II remodeling results from resorption of minerals for maintenance of physiological homeostasis.

The Smithsonian Institution preserved and housed all the skeletal material studied.

The 51 Eskimo skeletons came from Northern Alaska. Regarding their ages, Richman et al state:

“According to records in the dividision of Physical Anthropology, Smithsonian Institutino, material is both pre- and post- contact, from the late 1700s to early 1900s. However, settlers had little effect on Eskimo diet and life style [7], allowing consideration of the skeletal material as belonging to a homogeneous group.”

To establish that contact in this period had little influence on Eskimo diet, they cite: Rainey FG. The Whale Hunters of Tigara. Anthropological Papers of the American Museum of Natural History, 41. New York, 1947. I don’t have access to this paper. However, given that when Weston Price reached the Eskimos in the 1930s many still remained exclusively on their native diets, I am inclined to accept that contact had very little significant influence on Northern (i.e. more isolated) Eskimos in the early 1900s.

Eskimo Family. Image source:  Wikipedia

The 65 Pueblo skeletons came from pre- and post- contact periods also: 919 AD to the 1600s. Richman et al cite another researcher, Corrucini, who detected no differences in osteometric or odontometric traits in the pre- and post- contact specimens. About 90% of the Pueblo diet consisted of maize, beans, squash, and sunflower, with protein-poor maize accounting for 80-85% of the total. Thus they ate a 90%+ vegetarian, cereal-based, low protein diet.

 

Taos Pueblo, c. 1920.  Wikipedia

The 57 Arikara (Plains dwellers) skeletons also came from both pre- and post-contact times (1550-1845). Arikara ate maize, but unlike the Pueblo they combined it with meat and vegetables. The Arikara diet included red meat, fowl, fish, internal organs, fat, blood, eggs, berries, and tubers.

 

Arikara Warrior.  Wikipedia.

Richman et al found that “The populations did not differ significantly in numbers of type I resorption cavities or type I forming osteons. However, highly significant result were obtained with respect to type II resorption cavities and type II forming osteons.” The Eskimos had about 4 times more type II osteons than the Peublos, and almost twice as many type II osteons as the Arikara, indicating that the Eskimo bones had experience considerably more type II remodeling than the other two groups.

Eskimos had the highest occurrence of Type II resorption cavities, while Pueblos had a significantly lower number of these cavities and Arikaras had an intermediate number (which was not significantly different from either Eskimos or Pueblos). They found no evidence that age affected the incidence of type II remodeling (i.e. the incidence of type II remodeling did not differ with age in any of the populations). This indicates that the type II remodeling arose from a metabolic condition, not aging.

Richman et all suggested that the acidogenic character of the Eskimo diet would lead to greater urinary losses of calcium, which would cause a greater need to resorb bone calcium to correct blood calcium levels. This would explain why the Eskimo bones had the most evidence the type II resorption that occurs in the haversian canals adjacent to the blood vessels serving the osteocytes.

What About Precontact Eskimo Bones?

In 1979, Laughlin, Harper, and Thompson reported [2]:

“Our data from St. Lawrence Island (Yupik) Eskimos demonstrate a low degree of bone mineralization in both males and females, thus suggesting that a low bone mineral profile and rapid bone loss with advancing age is a condition common to all Eskimos regardless of their particular micro-environment (table 3). It is also apparent that this pattern has been the case in Eskimos for a considerable time prior to European contact.” [Italics added.]

These researchers also found that Eskimo bones had thinner cortices than those of Caucasians; their bones thus had both thinner and less dense cortices.

In 1981, Thompson and Gunness-Hey published “Bone Mineral-Osteon Analysis of Yupik-Inupiaq Skeletons”[3]. They analyzed nine different variables in skeletons from both post-contact and pre-contact Eskimo skeletons in comparison to skeletons of U.S. caucasians. They found “Eskimo femora to be thinner than those of U.S. whites.” Eskimo bones also had a greater porosity. They also reported:

“Similarities in cortical thickness, bone mineral index, and cortical bone density values between Kodiak Island (precontact) and St. Lawrence Island (postcontact) skeletons suggest no differences in bone remodeling between periods of contact among Eskimos from the same linguistic division (Yupik).”

Thus, these investigators appear convinced that precontact Eskimos had the same pattern of early-onset and accelerated bone mineral loss as partially modernized Eskimos.

Finally, in a paper entitled "The paleopathology of the cardiovascular system" (full text), Zimmerman reports the results of autopsies he performed on several naturally frozen bodies of ancient Eskimos.   The oldest one, dated to about 400 AD, was a 53 year old female from St. Lawrence Island.  It appears she died in an avalanche.  She had coronary and aortic atherosclerosis.

Two others came from Barrow, the northernmost community in Alaska, and dated to 1520 AD +/- 70 years, well before European contact.  The remains indicated that an entire family had died in their sleep trapped and killed by ice in a storm on the Arctic Ocean.  One female was 25 to 30 years of age and one 42 to 45 years of age.  The elder exhibited atherosclerosis.  According to Zimmerman, both "showed severe osteoporosis, the bone spicules being remarkably thinned and decalcified."  Read that again.  He found severe osteoporosis in a pre-contact Eskimo woman who was at time of death not more than 30 years of age. 

In upcoming posts I will discuss some of the other evidence of the effect of meat on metabolic acidity that leads me to select and recommend a diet with a net alkaline residues.

Thanks to Loren Cordain for assistance with this series, and especially for finding the Zimmerman paper.

1. Richman EA, Ortner DJ, and Schulter-Ellis FP. Differences in intracortical bone remodeling in three aboriginal American populations: Possible Dietary Factors. Calcif Tissue Int (1979) 28:209-214.
2. Laughlin WS, Harper AB, Thompson DD. New Approaches to the Pre- and Post-contact History of Arctic Peoples. Am J Phys Anthrop (1979) 51:579-588.
3. Thompson DD and Gunness-Hey M. Bone Mineral-Osteon Analysis of Yupik-Inupiaq Skeletons. American Journal of Physical Anthropology (1981) 55:1-7.