Re: diet & human evolution

Thanks for this post!

RBR

On Mon, 25 Jul 2005 02:44:50 GMT, st7 <st7@xxxxxxxx> wrote:

>John Sankey wrote:
>: where do modern people who rely totally
>> upon northern non-fish food sources get their birthright of
>> omega-3's for their brains? Laplanders and a few northern
>> Siberian tribes are about all that's left of the northern
>> 'Palaeolithic' diet. I'd appreciate references.
>
>The 'Paleolithic' diet is probably not a model to follow. The
>first 90% of the last 150,000 years of our evolutionary history
>is likely to be more biologically appropriate than the last 10%
>regarding cancer risks (and also likely, longevity):
>
>Urology. 2001 Apr;57(4 Suppl 1):31-8.
>
>Similarities of prostate and breast cancer: Evolution, diet, and estrogens.
>
>Coffey DS.
>
>James Buchanan Brady Urological Institute, The Johns Hopkins Hospital,
>Baltimore, Maryland 21287-2101, USA.
>
>Environment determines the risk of both prostate and breast cancer, and
>this risk can vary >10-fold. In contrast, no risk exists for human
>seminal vesicle cancer demonstrating tissue specificity. There is also
>species specificity, because there is no risk for prostate cancer in any
>other aging mammal except the dog. A study of evolution indicates that
>the prostate and breast appeared at the same time 65 million years ago
>with the development of mammals. All male mammals have a prostate;
>however, the seminal vesicles are variable and are determined by the
>diet so that species primarily eating meat do not have seminal vesicles.
>The exception is the human, who has seminal vesicles and consumes meat,
>although this is a recent dietary change. Human lineage departed from
>other higher primates 8 million years ago. The closest existing primate
>to humans is the bonobo (pigmy chimpanzee), which does not eat meat but
>exists primarily on a high fruit and fresh vegetable diet. Homo sapiens
>evolved only about 150,000 years ago, and only in the last 10% of that
>time (10 to 15 thousand years ago) did humans and dogs dramatically
>alter their diets. This is the time when humans domesticated the dog,
>bred animals, grew crops, and cooked, processed, and stored meats and
>vegetables. **All current epidemiologic evidence and suggestions for
>preventing prostate and breast cancer in humans indicates that we should
>return to the original diets under which our ancestors evolved. The
>recent development of the Western-type diet is associated with breast
>and prostate cancer throughout the world.** It is believed that the
>exposure to and metabolism of estrogens, and the dietary intake of
>phytoestrogens, combined with fat intake, obesity, and burned food
>processing may all be related to hormonal carcinogenesis and oxidative
>DNA damage. An explanatory model is proposed.
>
>PMID: 11295592 [PubMed - indexed for MEDLINE]
>
>some excerpts from the full paper:
>
>"There appear to be very similar lifestyle risk factors accompanying
>both prostate and breast cancer, including a lower risk associated with
>high intake of fruits, vegetables, fiber, and soy products and,
>alternatively, a higher risk associated with increased intake of red
>meat, animal fats, dairy products, and steroid exposure, as well as body
>mass and birth weight."
>
>"Approximately 7 million years ago humans evolved from a common ape
>ancestor, with our closest relative being the pigmy chimpanzee called
>the bonobo. Like the other great apes, the bonobo eats primarily fruits
>and vegetables and no meat."
>
>"Other types of chimpanzees occasionally eat meat as opportunist
>scavengers, sometimes even with very limited hunting. Even in humans,
>highly effective hunting was not the major source of high meat caloric
>intake until later in human development. When early hominoids such as
>"Lucy" came down from the trees 4 million years ago and began to roam
>the savannas, they picked up the ability to become hunter-gatherers."
>
>"This major phase shift in food style occurred only about 10,000 years
>ago, when humans became farmers and domesticated both plants and
>animals. This technology quickly evolved into a tighter focusing of
>human diets from wild fresh vegetables and fruits to an eating pattern
>toward limited plants that could be domesticated and grown in great
>quantities and stored, like wheat, rice, barley, corn, potatoes, and
>other tubers. This resulted in approximately 20 plant types rapidly
>replacing the high diversity of 3,000 plants and fruits that were
>earlier eaten fresh as they came into season and were gathered from the
>wild. With large-scale domestication and breeding of cattle came a high
>meat intake, and this was combined with storage, curing, drying, and
>cooking as well as a propensity to use milk and cheese from dairy
>processing. Cooking, burning, and smoking produce high levels of
>heterocyclic molecules, many of which make adducts to DNA, and are
>carcinogens."
>
>"Since separating from the great apes and chimpanzees approximately 8
>million years ago, humans evolved into Homo sapiens sapiens that are
>very similar to our present form in little as 150,000 years. However, we
>dramatically changed to a Western-style diet only in the very recent
>past (ie, 15,000 years)--at a pace much faster than we could
>biologically evolve (Table V). This Western diet consists of high meat
>and fat; dairy products; stored, processed, and cooked meats; and low
>fruit and fiber intake, along with a more sedentary lifestyle."
>
>"In summary, we were not biologically selected by the evolution process
>to eat the way we do today, and the damage is manifested in prostate and
>breast cancer. Indeed, all of the present suggestions of the National
>Cancer Institute and the American Cancer Society as to how Americans
>might reduce their chances of getting prostate and breast cancer revolve
>around adapting dietary changes in our lifestyle back toward the early
>human diet of more fruits; a variety of fresh vegetables and fiber; less
>burning, cooking, and processing; diminished intake of dairy products,
>red meat, and animal fats, as well as decreasing weight and increasing
>aerobic exercise. That is, we must return to a diet and lifestyle that
>more closely matches the first 135,000 years before technology modified
>our lifestyle and diet."
>
>TABLE V. Human development and the change of diet
>Time During Human Development (150,000 years)
>First 90% (135,000 years) ; Last 10% (15,000 years)
>Diet: high; low
>Fruit: high ; low
>Fiber: high; low
>Plant diversity: high (3000); low (20)
>Red meat: low; high
>Animal fat: low; high
>Dairy products: low; high
>Food: fresh/wild ; cooked/preserved
>Movement: High; Sedentary
>
>"Certainly, looking for simple relation will not be sufficient, but
>delineating the exact mechanisms of cell cycle control and stem cell
>development in prostate cancer should be helpful in understanding these
>early preneoplastic lesions and their relation to diet. In the end, we
>still must explain why approximately 90% of prostate and breast cancers
>are sporadic and acquired, and why only 10% are directly inherited in a
>Mendelian manner. The acquired cancers may indicate why this phenomenon
>is so geographically centered and may be capable of being altered. If
>these cancers are set in place within the neonatal or developmental
>periods, as has been proposed by many, then this process will require
>far more research to unravel the timing of these critical events."

.

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