Thursday, March 4, 2010

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.


Sterling Purdy said...

Just found your site. Look forward to reading it.

Aaron said...

I am still wondering if absolute protein matters. The Pueblos seems to have had the best dental health (and had lowest protein intake).

I also wonder -- is there a point in which trying to balance out protein with alkaline residues just does not work?

J. A. Deep said...

Don, Thanks for the great work!

Could bones be the difference? See WAPF blog post (by C. Masterjohn):

In a 1972 article, "Mental Illness, Biology, and Culture," published in the book Psychological Anthropology, Alfred Wallace hypothesized that hypocalcemic tetany from low levels of calcium and vitamin D underlied a phenomenon of hysteria found among Eskimos called pibloktok. Wallace noted that tetany was common among Inuit who did not have year-round access to fatty fish and fish bones, but that bone diseases were incredibly rare among the Inuit even when they faced seasonal malnutrition.

Thanks again!

Melissa said...

But in the acid base paradigm, grains are considered acidifying too...the Pueblo data seems to refute that.

Melissa said...

Good detective work, but reading the paper, another factor comes up, which is smoky indoor lamps these Inuit depended on. Soot is known to induce atherosclerosis.

shell_piece said...

Don, Im really enjoying this series, thanks! Its lead be to rethink my excess meat consumption having recently started to to get kidney discomfort. However im still skeptical. Have you read Lex Rooker's journal over at rawpaleoforum? He has been eating nothing but animal fat and protein with no plant food for more than 4 years, and a bone density scan not so long ago actually showed an increase in his bone density compared to his vegan days. All the bone scan data is posted in his journal here..

Don said...


I believe absolute protein does matter. More on that later.

J.A. Deep,

Wallace seems to have had a misconception about Eskimo bone health. I have another paper that reports that 36 of 80 Northern Eskimo skeletons showed vertebral compression fractures. Data does show a cline of bone density in Eskimos, with those in the south having better density than those in the north, yet all still showed thinner bones than age-matched whites.


Corn is one of the least acidic grains, generating 3.8 mEq/100g. Compare to brown rice 12.5 mEq/100g, and whole wheat 8.2 mEq/100g. Plus, Pueblos like other native American tribes used lime or volcanic ash, rich in alkalis (calcium, magnesium) to process the corn.

Yes, soot could cause atherosclerosis but I don't know of any evidence for it causing osteoporosis, do you? Very unlikely these Eskimos would have had MI, you need inflammation for that and in the absence of grains, I doubt they would have had inflammation enough to cause ruptures of the atherosclerotic plaque.


Read his post carefully. He said "This is my first DEXA scan so this becomes the base line." He can't claim an increase of bone density because he doesn't have a scan from his vegan days. For all we know he could have lost bone since then. The healing of oral disease does not prove remineralization of the skeleton either. Loss of bone in the mouth can be a local phenomenon due to inflammation and infection. That could heal while gradually losing bone mass. Eskimos also had good dental health.

Even if he did have good data, bone loss is a very gradual thing untili advanced age when drops of hormones increase the rate, so 4 years doesn't impress me. In addition he just might be one in a million who can eat that way without bone loss, you can't generalize from one case.

I don't know what all Rooker eats, but I sure wouldn't trust a diet of only meat and fat unless he also eats bones for minerals.

I just don't get why these people think that humans are exclusive carnivores. If it were the case, why do we find that even in wealthy nations people choose to eat a mixed diet, i.e. voluntarily seek out plant foods? The same reasoning applies against veganism, if humans aren't omnivores, then why do they voluntarily seek out animal foods. You won't find any cats choosing mixed diets. I know, they claim that cooked foods or plant foods are "addictive" or something like that.

Righ, so why do humans produce amylase, sucrase, and other carbohydrate digesting enzymes? And why do even highly carnivorous H-Gs have more copies of the AMY1 gene than chimpanzees?

Experimental data shows that dietary or metabolic acid residues can definitely scar the kidneys and increase calciuria.

Also, Rooker CLAIMS to have eaten nothing but animal food for 4 years. Sorry if I seem cynical, but raw vegan and "breatharian" gurus have also claimed to go for years without eating meat or cooked food, only to be exposed, some found eating at fast food restaurants.

In another post Rooker wrote: "We're all headed for the Pearly Gates no matter what we eat, and I expect that if our worst sin is eating a bit of cooked food on occasion, we'll still be admitted as souls in good standing." Sounds fundamentalist, suggesting that eating cooked food is a "sin" in a religious sense, judged by a great spook in the sky. Maybe he wrote that sarcastically or facetiously but it doesn't look like it to me.

Aaron said...

don -- is there a reference list for the amount of acid produced for grains-- I'd like to know the value for barley and others.

Ned Kock said...

Hi Don.

First of all, let me say that your analysis is very compelling. Thanks for putting these posts together.

I wonder about the acid-alkaline balance though. It is well known that bone density is heavily dependent on levels of physical activity, and the type of physical activity, at developmental stages (e.g., childhood). Children who jump, fall, bump into each other, even crack a bone here and there etc., and do that a lot growing up with an appropriate calcium intake, tend to be the ones with the strongest bones in adulthood.

From what I understand, bone loss at adulthood is strongly associated with hormonal changes and lack of physical activity (particularly lack of resistance exercise). An extreme example: lack of gravity leads to fairly accelerated bone loss. Poor intake of minerals may also be a problem, but bone minerals should not, under normal circumstances, have nearly the same type of turnover that one sees with micronutrients, such as vitamins (even the fat soluble ones).

The acid-alkaline balance may play a role in bone demineralization, but I am not sure that role is as important as some people think.

Level and type of activity in early childhood can change a lot from individual to individual. In just about any culture you’ll be able to find individuals with weak bones, and that may be due to early illnesses that prevented them from moving a lot, consuming enough or properly absorbing minerals, among other things.

Since you mention Weston Price, you are probably aware of his stance on the acid versus alkaline diet and its effect on bone loss. In short, he did not believe that an alkaline diet was associated with bone health. This was based on his analysis of the teeth of individuals in various cultures.

Here is a relevant quote from Price’s “Nutrition and Physical Degeneration”:

“My investigations are showing that primitive groups have practically complete freedom from deformity of the dental arches [and other dental problems] … [these problems] develop at the point of contact with foods of modern civilization. It is not my belief that this is related to potential acidity or potential alkalinity of the food but to the mineral activator content of the nutrition during the developmental periods …”

Note that Price does not mean, when he says the teeth problems “develop at the point of contact with foods of modern civilization”, that individuals who have well formed teeth develop bad teeth if they become westernized as adults. He means that new generations develop those problems upon westernization of the diet.

Metabolic disorders, on the other hand, often develop in the same generation upon westernization of the diet.

Don said...


You can find a list in The Paleo Diet by Cordain, The Encyclopedia of Healing Foods by Michael Murray, or get this paper by Remer and Manz: Potential Renal Acid Load of Foods and Its Influence on Urine pH.

Does not have some foods. Someone reproduced the list developed by Jurgen Vormanne at the Institute for Pevention and Diet (colleague of Remer and Manz) here:

It comes from this article by Vormann et al:

Supplementation with alkaline minerals reduces symptoms in patients with chronic low back pain.

Don said...


Most investigations find Eskimos have normal bone growth and mineralization (ages 0-30) but accelerated bone mineral loss thereafter. Price looked at orofacial development, not general skeletal aging. Tooth decay and osteoporosis are not the same disease or process. Price did not do any work looking at diseases of aging.

Mazess for example compared Eskimos still partially involved in traditional lifestyle (nearly 50% of subsistence) to whites in Wisconsin. I don't think activity can explain the difference in aging bone mass. Most likely Eskimos aged 40 years (already showing bone loss) doing some hunting got more intense activity (walking through snow, piloting kayaks, etc.) than whites aged 40 years living in Wisconsin in the 60s and 70s who probably got all their foods by driving an automobile to the supermarket.

Pueblos probably did not have more intense activity than Eskimos either. Trudging through snow is a lot more intense than walking through a desert. Hoisting seals and caribou is probably more intense than collecting corn cobs.

You state that you think bone minerals "should not, under normal circumstances, have nearly the same type of turnover that one sees with micronutrients, such as vitamins (even the fat soluble ones)." On what basis do you make this claim? Reality does what it does regardless of what we think it "should" do? Experimental data does not support your idea of what bone mineral "should" do, as I will show later. Moreover, the bones of Eskimos compared to Pueblos do not accord with your "should". Experimental data simply does not support the idea that bone mineral is a static repository unaffected by metabolic demands.

J. A. Deep said...

Hi Don,

Thanks for your reply above. I'm just wondering if it is the consumption of bones that makes the difference to the health of our own bones, whether fish bones for the Inuit, as mentioned on the Weston A Price blog, or bone broth or bone meal in other high-protein cultures?

It seems Weston Price came away with the observation that bones were among the sacred foods of the primitive cultures he studied. See e.g. Guts and Grease

Perhaps when primitive cultures are unable to obtain sufficient bones as food (or, today, throw the bones away!) they turn to vegetation, if it is available, or else, weaknesses are created in their own bones?

And to support your idea that the acid/alkali balance is crucial (which I learned here from you!), I'm guessing bones as food have a large alkali excess, given that their mineral content should be nearly ideal?

The lists of acid forming foods you've provided are very helpful, but don't seem to include bones?


Don said...

JA Deep,

I don't have data on the pH of bones or bone broth. However, I am skeptical of bones for the following reasons:

1. Southern Eskimos who had more bones than northern (from fish) still had early onset osteoporosis.

2. Sardines with bones have a net acid delivery of 13.5 mEq/100g.

3. Bones also contain phosphorus, abundantly supplied by meat, and also acid-forming, so bones may not have a net alkaline effect.

4. Some experiments show that no amount of calcium carbonate (alkaline) can counter the calciuric effects of very high protein diets.

5. To my knowledge, although chimps eat meat, they don't eat bones, and do eat fruits and vegetables. Thus, it seems likely that consumption of fruits and vegetables predates bone consumption in hominin evolution, so it would seem more likely that our metabolism requires the bicarbonate in plants more than just the minerals in bones. I would be more inclined to reverse your guess, and say that people try resorting to bones when they can't get fruits and vegetables, not that they resort to fruits and vegetables when they can't get bones.

The key is that fruits and vegetables provide organic compounds that convert to bicarbonate in the blood. This neutralizes acid without resulting in mineral loss. Calcium can only buffer urine by joining acid in excretion.

J. A. Deep said...

Yes, Don, points all well-taken. Thanks very much for the response. You've made a difference for me in my life and I hope in others.

Anonymous said...

Lex Rooker eats about 65 percent fat and 25 percent protein, mostly ground beef, and includes ground organ meats as well. I just posted my interview with him:

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