Re: diet & human evolution
- From: st7 <st7@xxxxxxxx>
- Date: Mon, 25 Jul 2005 02:44:50 GMT
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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