To: All Paleodieters
From: Brian J. MacLean
Re: Response to Loren Cordain and Sally Fallon and Mary Enig

This letter is in Reponses to comments made by Loren Cordain on November 18,
1998 and by Sally Fallon and Mary Enig on December 4, 1998 to a letter I
posted on November 16,1998 ( Paleo Querries). I apologize for the delay in
response, but I have been off the net and intensively 'studying' free
radicals' effects on the skin in the Florida and California sun ( Loren's
right-there's really something to that theory- I've got all kinds of new
wrinkles!). I t was a pleasure to return and find the interesting above
responses to my 'Paleo Querries.' 

In reply to Loren Cordain's points:

1. I stated that  " The available information on Paleolithic peoples is so
scanty that it seems specious to believe that one can follow their
nutritional practices with more than a modicum of accuracy." Loren responded
that by studying paleodiets, "there are some obvious deductions which allow
basic generalizations which have enormous impact upon present day health
(i.e., dairy products could not have been a component of stone age diets)."
It seems that if the deductions are 'obvious', then one need not resort to
in-depth   detective work of questionable validity on 'paleolithic' diets to
conclude the deleterious effects of most "modern" foods. A considerable body
of literature exists in nutritional research, which clarifies the nature of
many of the more harmful "new" foods (e.g., Trans-fatty acids and refined
carbohydrates). As for fatty meats and dairy products, valid inferences
cannot be drawn within our cultural matrix with the current information. To
make definitive statements regarding these latter foods' effects in our
culture, it would be necessary to partial out the variance contributed by
modern agricultural and preparation methods. Cross-cultural studies suggest
that these food categories require a more sophisticated analysis with regard
to their place in human nutrition than the     dichotomous thinking often
displayed in nutritional circles.
 
2. Loren Cordain stated: "The information that has been garnered by
ethnologists and anthropologists has value and provides insight into what
the components of the completely aboriginal diet would have been prior to
contact and acculturation." It is true that available data on macronutrient
ratios among aboriginal peoples provide interesting anthropological
information. However, there appears to be little information in
anthropological works on micronutrient ratios among aboriginal peoples,
which is at least as critical in understanding dietary effects as
macronutrient information. Furthermore, it is unclear how aboriginal
nutritional practices have much relevance for current psychosocial
conditions, which include requirements for sustained attention under low
motor activity levels (e.g., school), as well as coping with a panoply of
relatively new environmental toxins. Oriental cultures have known for
millennia that dietary needs vary according to activity levels. For example
in most spiritual traditions from the Indian subcontinent, China and Japan,
a high carbohydrate, low fat, low protein diet with  few animal foods has
been considered most ideal for contemplative practices.

 3. With regard to Loren Cordain's statement that the "reported longevity of
Hunzas and Vilcambas may have a genetic component which is independent of
environmental factors," some evidence suggests that peoples in contiguous
areas to that of the Hunzas share a similar genetic history, but have a
considerably different nutritional pattern, as well as less favorable
pathology profiles and longevity rates(1). 

4. With regard to Loren Cordain's statement about "Harman's classic free
radical theory…generally accepted as a contributor to the aging process by
most nutritionists and gerontologists," a number of points need to be made.
First, free radical theory is only one of at least six major theories of
aging, and is by no means accepted by all researchers as a causal factor in
aging (2). The inclusion of antioxidants in the diet, which scavenge free
radicals, has been found to improve aging biomarkers such as  tissue age
pigments   ( 3). However, in rodent studies, the administration of free
radical scavengers has not unequivocally prolonged maximum life span ( 4, 5,
6). For a review of  survival curves from populations administered
antioxidants, see Walford, 1986, p.389 (4). Although there is considerable
evidence that free radicals are associated with tissue damage, it is not
clear whether they exert a causal influence (7, 6 ). Weindruch and Walford
(6) contend that caloric restriction is the only known method of prolonging
maximum life span. Finch (8) states  that "caloric restriction is the only
known environmental means to alter the acceleration of mortality rate(MRDT)
in any mammal." Harman (9) points out that although average life span of
mice has been easily increased with antioxidant treatment, "the increases
were not accompanied by any certain extensions of maximum life spans." Loren
may wish to read  in the article he referenced  (Harman, 9, p. 7127) that
"the question remains, now as in 1954: are free radical reactions the sole
cause of aging, the major cause, or a minor contributor to the process?" It
seems that  aging is most likely a dialectical multi-factorial process, and
thus not approachable by  a reductionist analysis. Rather, it may resemble a
fractal surface where a higher order dimension is greater that the sum of
its components.

5. With regard to Loren's point 6, in which he states that "most
nutritionists would agree that diets high in fruits and vegetables such as
the 'paleodiet' would be healthful not only during the reproductive years,
but also during the post-reproductive years," the issue of  quantity of food
intake also seems germane to longevity.  A study by Ross and Bras (10) is
illustrative of the point made in my November letter that perhaps the
paleolithic diet was "evolutionarily selected because it was the most
effective to develop the human form for the first two decades of life with
the goal of effective reproduction." Ross and Bras  found that rats given
the opportunity to self select food types and quantities chose to maximize
body growth, development and most likely fecundity rates, at the expense of
individual health and survival. This ad lib group also experienced a
significantly higher rate of tumor growths and other pathologies.

6. As to Loren's Santayana quote, "Those who cannot remember the past are
condemned to repeat it," one could as easily apply this statement in a
different direction than intimated by Loren. We might consider this quote as
an admonition to "20th century man and his fledgling science" that
paleolithic man's "eons of evolutionary experience… that is still far wiser
than the mind" of contemporary man , eventuated in the abandonment of the
hunter-gatherer lifestyle and diet  in favor of agricultural practices.

In reply to Sally Fallon and Mary Enig's points:

1.  Sally and Mary stated that "the greatest longevity among inhabitants  of
Soviet Georgia is found in those who consume the most meat and fat." It
appears that such a                 conclusion is questionable in that we
now know that it is difficult to ascertain birth dates due to faulty or
absent record keeping and dissimulation for cultural reasons ( 11). 

2. Sally  and Mary stated: "No good studies have shown that calorie
restriction contributes to a longer life in humans." First, at the risk of
belaboring the obvious, much of our biomedical knowledge has been obtained
from animal research. Specific small- scale physiological processes are not
always applicable to cross species comparisons. For example, primates are
incapable of vitamin C synthesis, while most rodents have this capability.
Large-scale general physiological processes, on the other hand, can often be
extrapolated from one species to another (e.g., immune system functioning
among mammals). Dietary restriction decelerates aging in a variety of
poikilotherms (12,13,14) and homeotherms  (6). Although this is  not
definitive proof that the same results would be found in a human population,
it seems that similar results would be found with a high degree of
probability. A second area which may provide suggestive evidence regarding
human longevity, is cross-cultural studies. Remaining cognizant of the
aforementioned difficulties in establishing accurate birth records, the
apparent longevity of the Hunzas may be associated with a low daily caloric
intake:  an estimated average of 1900 calories per day (15). In Okinawa,
where accurate birth records have been kept since the latter part of the
19th century, the calorie intake of school children is only 62% of what is
recommended for Japan and the longevity incidence appears to be the highest
in the world (16).

3. Sally and Mary stated: "The Framingham study found that those who
consumed the greatest number of calories weighed the least, had the lowest
serum cholesterol and were the most physically active." This study is flawed
in a number of respects and makes the above statement difficult to
interpret. The percentage of nicotine users in the most overweight group of
the original Framingham study was 55% while over 80% users in the most
underweight group (17). The possible effects of this contaminating variable
difference between groups makes it difficult to link  caloric intake levels
with reliable biomarkers or increased life span. Physical activity levels
have not been found to be consistently related to longevity. A National
Institute of Aging study  found that in rats fed ad lib, exercise increased
longevity while decreasing  it in the very extended life spans of calorie
restricted rats (18). Furthermore, Sally and Mary have pointed out many
times that cholesterol is a 'bogus issue' and of no relevance to coronary
heart disease, and thus to longevity. 

4.Sally and Mary stated: "Animal studies showing reduced numbers of tumors
in animals on restricted-calorie diets also found that the
restricted-calorie groups had larger and more virulent tumors than those on
non-restricted diets."  In the Ross and Bras (19) and Ross (20) studies,
those rats on dietary restriction showed about one-half the total number of
tumors as controls, while showing an increase in skin carcinomas. The
incidence of skin carcinoma, however, was small in both control and
experimental groups (Figures 1 and 2, Ross & Bras, 19). Furthermore, the
degree of dietary restriction in these studies was greater than most other
studies (approximately 30% ad lib), and may be a case of malnutrition rather
than calorie restriction with adequate nutrition. It is also noteworthy
that the onset age of these carcinomas in the dietary restricted animals was
consistently later in their lives than found in the ad lib animals. Under
conditions of less restriction of calorie intake, these tumor growth results
are usually not found (21,6).


General Comments:

It appears that in the Paleo Diet writings and in the Price-Pottenger
Foundation literature, there is an underlying assumption that the ancient
and aboriginal ways of eating are closer to the heart of dietary wisdom,
that is, are somewhat more consistent with 'natural law'. This  assumption
seems to a large extent dependent on a inference  from observations of the
statistical frequency of eating patterns in populations to an imperative
regarding how human beings 'ought' to eat. Although these writings are
informed by   research in the biological sciences, the primary impetus and
direction seem to arise from findings in paleontology and anthropology. This
could be seen as a case of the 'naturalistic fallacy' where a leap is made
from an 'is' statement to an 'ought' statement. This issue is complex and
requires considerably more discussion than is suitable for this particular
forum. Suffice it is to point out that many 'natural' practices by our
pre-civilized ancestors and present day aboriginal peoples fall far short of
Loren's "far wiser than the mind of  20th century man" criterion. Paleo
adepts and Price-Pottenger writers in particular should take note that
primitive 'natural' eating practices such as eating animal flesh raw
(including human)  has often proved disastrous. Kuru, a TSE disease among
the Fore people of New Guinea, was transmitted by the 'natural' aboriginal
practice of honoring close relatives by eating them after they died (22). In
another area of the world, evidence from the ancient Americas has shown that
the assumption of the evolution of parasites subsequent to developed
agriculture and livestock domestication, was wrong (23). Mummy remains from
the  Chinchorro, a tribe from northern coastal Chile between 550 to 500
B.C., show that they were infested with a sea lion tapeworm (D.pacificum),
resulting in pernicious anemia, leading to porous skeletons, weakness and
death. These peoples, like many other aboriginal peoples, enjoyed the
'natural' practice of eating their sea food raw. Despite what modern day
Rousseauians would like to believe, not all things that are untainted by
civilization are good.

                                                                Sincerely,


Brian J. MacLean Ph.D.
Psychologist

                                                          References

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