תזונה ותוספים אבולוציה, האדם הקדמון, בשר, CVD, בריאות וכו'

[Mike Bikov]

Eur J Clin Nutr. 2002 Mar;56 Suppl 1:S42-52.Click here to read Links
The paradoxical nature of hunter-gatherer diets: meat-based, yet non-atherogenic.
Cordain L, Eaton SB, Miller JB, Mann N, Hill K. Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado, USA. [email protected]
OBJECTIVE: Field studies of twentieth century hunter-gathers (HG) showed them to be generally free of the signs and symptoms of cardiovascular disease (CVD). Consequently, the characterization of HG diets may have important implications in designing therapeutic diets that reduce the risk for CVD in Westernized societies. Based upon limited ethnographic data (n=58 HG societies) and a single quantitative dietary study, it has been commonly inferred that gathered plant foods provided the dominant energy source in HG diets. METHOD AND RESULTS: In this review we have analyzed the 13 known quantitative dietary studies of HG and demonstrate that animal food actually provided the dominant (65%) energy source, while gathered plant foods comprised the remainder (35%). This data is consistent with a more recent, comprehensive review of the entire ethnographic data (n=229 HG societies) that showed the mean subsistence dependence upon gathered plant foods was 32%, whereas it was 68% for animal foods. Other evidence, including isotopic analyses of Paleolithic hominid collagen tissue, reductions in hominid gut size, low activity levels of certain enzymes, and optimal foraging data all point toward a long history of meat-based diets in our species. Because increasing meat consumption in Western diets is frequently associated with increased risk for CVD mortality, it is seemingly paradoxical that HG societies, who consume the majority of their energy from animal food, have been shown to be relatively free of the signs and symptoms of CVD. CONCLUSION: The high reliance upon animal-based foods would not have necessarily elicited unfavorable blood lipid profiles because of the hypolipidemic effects of high dietary protein (19-35% energy) and the relatively low level of dietary carbohydrate (22-40% energy). Although fat intake (28-58% energy) would have been similar to or higher than that found in Western diets, it is likely that important qualitative differences in fat intake, including relatively high levels of MUFA and PUFA and a lower omega-6/omega-3 fatty acid ratio, would have served to inhibit the development of CVD. Other dietary characteristics including high intakes of antioxidants, fiber, vitamins and phytochemicals along with a low salt intake may have operated synergistically with lifestyle characteristics (more exercise, less stress and no smoking) to further deter the development of CVD.







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Mayo Clin Proc. 2004 Jan;79(1):101-8.Click here to read Links
Comment in:
Mayo Clin Proc. 2004 May;79(5):703; author reply 703-4, 707.
Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: how to become a 21st-century hunter-gatherer.
O’Keefe JH Jr, Cordain L.
Mid America Heart Institute, Cardiovascular Consultants, Kansas City, MO 64111, USA. [email protected]
Our genetic make-up, shaped through millions of years of evolution, determines our nutritional and activity needs. Although the human genome has remained primarily unchanged since the agricultural revolution 10,000 years ago, our diet and lifestyle have become progressively more divergent from those of our ancient ancestors. Accumulating evidence suggests that this mismatch between our modern diet and lifestyle and our Paleolithic genome is playing a substantial role in the ongoing epidemics of obesity, hypertension, diabetes, and atherosclerotic cardiovascular disease. Until 500 generations ago, all humans consumed only wild and unprocessed food foraged and hunted from their environment. These circumstances provided a diet high in lean protein, polyunsaturated fats (especially omega-3 [omega-3] fatty acids), monounsaturated fats, fiber, vitamins, minerals, antioxidants, and other beneficial phytochemicals. Historical and anthropological studies show hunter-gatherers generally to be healthy, fit, and largely free of the degenerative cardiovascular diseases common in modern societies. This review outlines the essence of our hunter-gatherer genetic legacy and suggests practical steps to re-align our modern milieu with our ancient genome in an effort to improve cardiovascular health.



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Eur J Nutr. 2000 Apr;39(2):71-9.Click here to read Links
Dietary lean red meat and human evolution.
Mann N.
Department of Food Science, RMIT University, Melbourne, VIC, Australia. [email protected]
Scientific evidence is accumulating that meat itself is not a risk factor for Western lifestyle diseases such as cardiovascular disease, but rather the risk stems from the excessive fat and particularly saturated fat associated with the meat of modern domesticated animals. In our own studies, we have shown evidence that diets high in lean red meat can actually lower plasma cholesterol, contribute significantly to tissue omega-3 fatty acid and provide a good source of iron, zinc and vitamin B12. A study of human and pre-human diet history shows that for a period of at least 2 million years the human ancestral line had been consuming increasing quantities of meat. During that time, evolutionary selection was in action, adapting our genetic make up and hence our physiological features to a diet high in lean meat. This meat was wild game meat, low in total and saturated fat and relatively rich in polyunsaturated fatty acids (PUFA). The evidence presented in this review looks at various lines of study which indicate the reliance on meat intake as a major energy source by pre-agricultural humans. The distinct fields briefly reviewed include: fossil isotope studies, human gut morphology, human encephalisation and energy requirements, optimal foraging theory, insulin resistance and studies on hunter-gatherer societies. In conclusion, lean meat is a healthy and beneficial component of any well-balanced diet as long as it is fat trimmed and consumed as part of a varied diet.

😛:P:P:P
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[Sugarzaza]

חחח, כן, אף אחד לא צד בשרים שמנים מחיות גדולות, הרי זה ידוע שהרבה יותר קל לתפוס איילה מבהמה וגם הבשר שלה מספיק להרבה יותר זמן!!

 

[bentzurm]

cordain שינה קצת את היחס שלו לשומן רווי בשנים האחרונות (שים לב שהמאמרים שפירסמת הם מלפני 6-12 שנים).
הנה ציטוט מתוך ה- Paleo Q&A מהניוזלטר שלו:

Saturated fatty acid intake and the risk of developing cardiovascular disease (CVD) is a topic with a lot of controversy. In recent years a wide body of research has suggested that increased consumption of certain saturated fatty acids (Lauric acid, myristic acid and palmitic acid) down-regulate LDL receptor and thereby increase LDL plasma levels, which has been associated to increased risk of CVD. On the other hand, stearic acid (a 18 carbon saturated fatty acid) has been shown to decrease LDL plasma levels. However, this view is too simplistic as there are several other factors contributing to CVD, such as smoking, exercise, trans-fatty acids, increased omega-6/omega-3 ratio, free-radicals, nutrient deficiency, homocysteine, alcohol intake and low-grade chronic inflammation among others.

Moreover, some studies have suggested that there’s not enough scientific data to support the view that increased total or LDL cholesterol is an independent risk factor for CVD, but rather oxidized LDL. Plaque production is mediated by oxidized LDL, not LDL. Oxidized LDL can produce shedding of the inner layer of the artery namely glycocalix. Oxidized LDL then infiltrates the intima of the artery. Oxidized LDL is eaten by macrophages, a process known as phagocytosis, causing macrophages to be transformed into foam cells which produce the fibrous cap.

Once the fibrous cap has been produced we need to break it down in order to produce an ischemic event. Lectins and low-grade chronic inflammation are involved in the activation of matrix metalloproteinases which break down the fibrous cap.

In summary, high total cholesterol or LDL levels do not increase CVD risk--rather oxidized LDL increases risk of CVD. To produce oxidized LDL requires the factors mentioned above. Hence, consumption of saturated fatty acids is not an issue if we control several other factors such as those mentioned.

Dr. Cordain wrote a book chapter and published a paper (with our team member Pedro Bastos) where he shows that saturated fat consumption in ancient hunter-gatherer populations were usually 10-15% above the recommended 10% of energy from saturated fats, yet they were non-atherogenic.

The bottom line is that we do not recommend cutting down saturated fatty acid intake, but decreasing high-glycemic load foods, vegetable oils, refined sugars, grains, legumes and dairy.​