Nicola
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The protective effect of raw food | Quote: | The high consumption of meat and dairy products is undoubtedly the major cause of atherosclerosis in modern times. However, long research by Dr Edward Howell indicates that the animal protein, fat and cholesterol contained in meat and dairy products are far less harmful if these foods are consumed raw.
Raw meat contains the proteolytic enzyme cathepsin and the fat-digesting enzyme adipose lipase. All animal fats, raw, contain lipase. When animal protein or fat is consumed raw, the enzymes accomplish a certain amount of predigestion in the cardiac (upper) stomach before being inactivated by the stomach acid further down, and so the final digestion of these substances in the intestine is more complete and they are assimilated in a relatively harmless form.
It has always perplexed nutritionists how primitive Eskimos and Masai natives could maintain good health as long as they do on diets consisting of almost lethal quantities of animal protein and fat. The answer to that puzzle, according to Dr Howell, is that apart from other lifestyle factors in their favor, these people, like the wild carnivorous animals, eat most of their food raw. (The name Eskimo is derived from the Cree Indian expression: "he eats meat raw".)
Dr Howell blames the cooking of food for practically every disease known to man. He points out that raw milk, containing 35 different enzymes, is an entirely different substance to the pasteurized dairy products of today, which are known to contribute to atherosclerosis. In his paper, "Lipase versus Cholesterol" (1983), Dr Howell says:
"Lipase is destroyed by cooking. Could it be that the bad reputation of cholesterol starts in the human digestive tract when fat, divorced from its lipase companion, is forced to remain idle and unaltered in the stomach during the period of 2 or 3 or more hours after it is swallowed? While ptyalin and then pepsin digest carbohydrate and protein in the stomach, lipase is absent and fat cannot be digested. But when fat is eaten raw, with its lipase undamaged by heat, it also can be digested in the upper stomach prior to the time the acidity becomes strong enough to prevent further action.
"When unaltered fat, deprived of its lipase companion, must confront strong hydrochloric acid in the human stomach, it faces a new and harsh experience. It may be left with a structural defect, or impairment with some undesirable trademark that prevents it from being properly digested in the intestine and hence improperly metabolized when it reaches the body tissues later. It must be remembered that in both animals and humans, it is impossible to prevent fat plus lipase from engaging in initial digestion during the first hour in the stomach.
"It has been shown that even ptyalin, which is more effective on starch near neutral pH, digests in the cardiac and fundic portion of the stomach for a period approaching an hour. The lipase associated with fat, in common with other food enzymes, has a pH optimum further down on the acid side of the pH scale, and therefore can be expected to digest fat in the upper stomach (the food-enzyme stomach) for a period at least as long as ptyalin can work on starch. This happens every day in the stomachs of millions of wild animals, and for epochal periods before the cooking era, evolution contrived to make it a regular scheduled event in the human stomach. It appears, therefore, that fat is being denied its traditional digestive rites during its passage along the digestive tract. And this may well be the reason that animals and humans, eating raw fat with its lipase, are immune to cardiovascular disease. Thus a strong reason emerges why research to explore this promising area is long overdue and merits top priority for allocation of research funds." |
Nicola
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Sol
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Hi Nicola,
Nice article. Thank you. Enzymes and digestibility is a big part of the reason I eat most of my meat raw.
Can you please give a link to the reference, if you found the article on the web, or tell us what book you got it from if you typed it in?
Thanks.
Sol
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Nicola
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| Sol wrote: | Hi Nicola,
Nice article. Thank you. Enzymes and digestibility is a big part of the reason I eat most of my meat raw.
Can you please give a link to the reference, if you found the article on the web, or tell us what book you got it from if you typed it in?
Thanks.
Sol |
http://www.soilandhealth.org/02/0...ibcat/020121horne/020121ch10.html
Nicola
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Sol
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Wow, Nicola. You sure do quite a bit of reading. And you find very interesting stuff too. Thanks!
Sol
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AlexF
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I am still on the fence regarding the nutritional benefits of raw versus cooked animal products.
For example we've all read about the Avidin content in raw egg whites which inhibits Biotin absorbtion by binding with it. Once cooked, the Avidin protein is denatured and its effects nullified.
http://www.worthington-biochem.com/AV/default.html
| Quote: | Avidin is a glycoprotein found in raw egg white. It combines stoichiometrically with biotin. The toxic effect of uncooked egg white which causes a syndrome similar to that of vitamin B deficiency (Boaz 1924) led to the discovery of the vitamin biotin (Gyorgy 1931, 1939). The toxic factor, first isolated by Eakin et al. (1940, 1941) who named it avidin, combines with the essential growth factor resulting in a "non-digestible" avidin-biotin complex which is not absorbed from the intestine or from the surrounding medium by microorganisms. Avidin plays an important role in biotin function studies and in the study of several enzymes in which biotin is a coenzyme. Avidin or avidin subunits bound to a matrix have been utilized for affinity purification (Berger and Wood, 1975; Green and Toms, 1973).
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Lets look at enzymes and the effects of heat and PH on their efficacy...
http://www.biotopics.co.uk/other/enzyme.html
| Quote: | Within the normal range, changes in temperature, pH, and concentrations of substrate and enzyme affect the rate of reaction in accordance with predictable interactions between enzyme and substrate molecules.
- The effects of temperature may be explained on the basis of kinetic theory - increased temperature increases the speed of molecular movement and thus the chances of molecular collisions, so within a narrow range (often 0-45 °C), the rate of reaction is proportional to the temperature. It is often said that an enzyme's rate of reaction doubles for every10° C rise in temperature. In this respect, the biochemistry of enzymes is similar to chemistry as studied elsewhere, However, the interaction between this positive effect of increased temperature and the negative effect described below results in a different situation, so that enzymes may be said to have an optimum temperature for their action.
- Changes in the pH probably affect the attraction between the substrate and enzyme, and thus the efficiency of the conversion process. Often, there is an optimum pH - near to pH 7 (neutral) in intracellular enzymes, and either in the acidic range (perhaps pH 1- 6) or in the alkaline range (pH 8-14) for different digestive enzymes.
- Some enzymes work better if other substances are also present. Some enzymes (pepsin - from the stomach) work better if acid is present (see above), and some, e.g. lipases are more effective if emulsifying agents are present because they break up the substrate into smaller droplets.
Above normal temperatures (say 60 °C), heat alters irreversibly the enzyme molecule. This denaturation is due to molecular vibrations (caused by heat) which change the shape of the protein, altering the folding and internal cross-linkages in its polypeptide chains. These changes - especially in the region of the active site - mean that the enzyme is inactivated, even when returned to normal temperature.
It would be wrong to say that an enzyme is KILLED by heat, since it is only a molecule, not an organism.
However, misconceptions of this sort are easily spread (see the BASC enzymes booklet!)
The higher the temperature to which the enzyme is subjected and the longer the heating is continued, the greater the proportion of damaged enzyme molecules and the result is that the conversion process becomes less and less efficient.
Below normal temperatures, enzymes become less and less active, due to reductions in speed of molecular movement, but this is reversible, so enzymes work effectively when returned to normal temperature.
Enzymes are sometimes adversely affected by other chemical substances which combine with them, either at their active site or by altering the overall shape of their molecule. Many drugs and poisons have their effect in this way.
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The above would lead me to believe that all or most enzymes are destroyed by heating food.
BUT
From: http://www.beyondveg.com/tu-j-l/raw-cooked/raw-cooked-2a.shtml
| Quote: | We won't try to be exhaustive here, but our intention is to show by means of examples that, depending on the food and on the temperature and duration of cooking, a food can become more, or less, digestible, so that no general rule can be inferred.
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| Quote: | | ...heating (above 100°C, or 212°F) decreases meat protein digestibility. |
| Quote: | ...the effects of heating on the digestibility of the protein in hake, a type of fish. Fish meat heated for 10 minutes at 130°C (266°F), showed a 1.5% decrease in protein digestibility. Similar heating of hake meat in the presence of potato starch, soy oil, and salt caused a 6% decrease in amino acid content.
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So yeah, I'm still on the fence about the whole cooked versus raw debate.
The one benefit I get from eating meat raw, particularly ground beef or skirt steaks, is that I get a NOTICEABLE energy boost about 10 minutes after consuming said meats. The more cooked a cut of meat is, the less pronounced the "energy boost" is.
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Kristelle
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http://www.rawpaleo.com/articles.html
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Nicola
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This is a copy from the rawpaleo forum:
Actually, eggs are much better raw than cooked. For one thing, cooking the eggs creates unhealthy toxins, which is problematic. Plus, the enzyme-inhibiting avidin in raw eggwhites is removed if the egg is fertilised(as would mostly be the case when eggs were taken from wild birds during Palaeo times), thus increasing absoprtion. Nowadays, of course, it's rare for people to get hold of fertilised eggs, so it's probably a good idea to limit egg consumption, if the later are unavailable.
Come to think of it, there was a recent study mentioned in the papers
linking increased (cooked-)-egg consumption(7 or more cooked-eggs a
week) to a much higher risk of early death - while there have been a
number of flaws in that study's methodology, it does indicate further
research in that area is warranted:-
http://tinyurl.com/5of54b
Nicola
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