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In an essay on this site, I wrote the following:
QUOTE: Mutat Res. 2002 Sep 30;506-507:9-20. "Comments on the history and importance of aromatic and heterocyclic amines in public health." Weisburger JH.
"The carcinogenic risk of aromatic amines in humans was first discovered when a physician related the occurrence of urinary bladder cancer to the occupation of his patients. They were employed in the dyestuff industry, chronically exposed to large amounts of intermediate arylamines�?Epidemiological data suggest that meat eaters may have a higher risk of breast and colon cancer. HCAs induced cancer in rats in these organs and also in the prostate and the pancreas. In addition, there is some evidence that they affect the vascular system. The formation of HCAs during cooking can be decreased by natural and synthetic antioxidants, by tryptophan or proline, or by removing the essential creatine through brief microwave cooking prior to frying or broiling. The amounts of HCAs in cooked foods are small, but other components in diet such as omega-6-polyunsaturated oils have powerful promoting effects in target organs of HCAs. On the other hand, the action of HCAs may be decreased by foods containing antioxidants, such as vegetables, soy, and tea�?Possibly, the carcinogenic effect of HCAs is accompanied by the presence of reactive oxygen species (ROS), which are also inhibited by antioxidants..."
Finally, from a recent report: "...The researchers couldn't explain why eating more animal fat was associated with breast cancer risk. It may be that factors other than fat are involved. For instance, grilling red meat can create cancer-causing chemicals�?Earlier studies had suggested one reason for the increased cancer risk, relating this to the heterocyclic amines (HCAs) that form when red meat is cooked at high temperatures (like frying and grilling), especially well-done. In laboratory studies, HCAs bond to estrogen receptors and create estrogen-like effects. In earlier research with
women past menopause, those who consistently ate hamburger, beef steak and bacon very well done thus getting high levels of HCAs -had more
than four times the breast cancer risk in comparism with women who consumed these meats raw or medium done�?Like many carcinogens, HCAs have to be activated to be able to damage our DNA and pose cancer risk..."
Source: http://www.tribune.com.ng/22032007/hlt2.html UNQUOTE.
I just came across this new evidence, which supports the findings above:
Cancer Res. 2007 Dec 1;67(23):11455-62.
Abstract: During the cooking of meat, mutagenic and carcinogenic heterocyclic amines are formed, the most abundant of which, 2-amino-1-methyl-6-phenylimidazo[4-5-b]pyridine (PhIP), induces tumors of the prostate, colon, and mammary gland in rats. Humans consuming cooked meat are exposed to PhIP on a daily basis, yet few studies have assessed the effects of PhIP at dietary relevant concentrations. In addition to its genotoxic properties, recent studies have shown that PhIP can activate estrogen receptor-mediated signaling pathways at doses that are similar to those that may be present in the body following consumption of a cooked meat meal. In the present study, we examined whether such doses of PhIP can affect estrogen receptor-independent signal transduction via the mitogen-activated protein kinase (MAPK) extracellular signal-related kinase (ERK) pathway to influence proliferation and migration in the human mammary epithelial cell line MCF10A and the prostate cancer cell line PC-3. At doses shown to have a proliferative effect on MCF10A cells (10(-11)-10(-7) mol/L), PhIP induced a rapid, transient increase in phosphorylation of both MAPK/ERK kinase 1/2 and ERKs. Inhibition of this pathway significantly reduced the PhIP-induced proliferation of MCF10A cells and the migration of PC-3 cells. The data presented here show that levels of PhIP that approximate to human dietary exposure stimulate cellular signaling pathways and result in increased growth and migration, processes linked to the promotion and progression of neoplastic disease. These findings provide strong evidence that PhIP acts as a tumor initiator and promoter and that dietary exposure to this compound could contribute to carcinogenesis in humans.
And:
Cancer Res. 2007 Oct 1;67(19):9597-602.
TITLE: "The cooked meat derived genotoxic carcinogen 2-amino-3-methylimidazo[4,5-b]pyridine has potent hormone-like activity: mechanistic support for a role in breast cancer."
And:
Toxicol Lett. 2007 Feb 5;168(3):269-77. Epub 2006 Nov 16.
Abstract: Formed during the cooking of meat, the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4-5-b]pyridine (PhIP) is mutagenic and carcinogenic. Although the metabolism and mutational effects of PhIP are well defined, the early cellular and genomic events by which it can induce neoplastic transformation are not yet fully characterised. These early cellular responses to genotoxic doses of PhIP were examined in a human mammary epithelial cell, MCF10A. Using Western blotting, PhIP was shown to induce expression of the DNA damage response proteins p53 and p21(WAF1/CIP1), and to inhibit cell growth while activating G1 cell cycle checkpoint, a consequence of PhIP-induced DNA damage. Using low doses of PhIP (previously shown to activate oestrogenic signalling), PhIP increased proliferation in the oestrogen receptor (ER)-negative MCF10A cell line and to activate the mitogen-activated protein kinase (MAPK) pathway. Inhibition of this pathway significantly reduced the PhIP-induced cell growth of MCF10A cells. The work presented here suggests that, further to its genotoxic properties, at levels close to human exposure PhIP stimulates cellular signalling pathways that are linked to the promotion and progression of neoplastic disease. It is possible that a combination of these DNA damaging and growth promoting properties provide a mechanism for the tumourigenicity of PhIP, and may be key determinants for the tissue specificity of PhIP-induced carcinogenesis.
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Hans,
Would you agree that boiling lean cuts of meat would be healthy? There is no oxygen to oxidise the cholesterol. One of the other problems with meat, though, is the high tryptophan and methionine content in meats such as turkey. But all things aside boiled meat, from my research seems decently healthy, certainly much more healthy then grilling, frying, broiling, or baking.
I like to get 99% fat free chicken breasts. I cut them into cubes and then boil them in water until they are no longer pink. Then I usually eat it with a potato or something. |
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| I guess boiling would be better, but perhaps by only a little - it's hard to say unless you compare things exactly (type of meat, cooking technique, amount of time cooked, etc.). I don't really see any advantage to eating meat (gelatin supplements seem like a good idea, in small amounts), and when studies have looked at dairy/eggs vs. meat, the difference appears significant, so why bother with meat? As in the study I cited above, it's the HCAs in conjunction with a lot of PUFAs that seem really bad, and the article Bruce cited did not control for this factor. "Abstracts" come in many "flavors." Sometimes there are obvious flaws, whereas is others it's clear that they found something that might be very important. Then, it usually pays to look at the entire study and think in terms of how it fits into the evidence that you've already examined closely. |
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I just came across a report of a study that suggests that folic acid "fortification" of flour may be even worse than I had already heard:
QUOTE: "It is important to note that these adverse interactions between high folate blood levels and vitamin B12 deficiency were seen only in the study participants from the NHANES conducted between 1999 and 2002, after the fortification of flour and other cereals with folic acid," says Selhub, who is also a professor at the Friedman School of Nutrition Science and Policy at Tufts University... UNQUOTE.
The problem is that:
QUOTE: Homocysteine and methylmalonic acid, compounds used by enzymes that contain vitamin B12, accumulate in the blood in patients who are vitamin B12 deficient. "Finding that the combination of high blood folate levels and low vitamin B12 status is associated with even higher levels of these compounds is a strong indication that the high folate is interfering with the action of these B12-containing enzymes, thus resulting in the exacerbation or worsening of the vitamin B12 deficiency," says corresponding author Jacob Selhub, Ph.D... UNQUOTE.
Source of the quoted passages:
http://www.sciencedaily.com/releases/2007/12/071218101124.htm |
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"As in the study I cited above, it's the HCAs in conjunction with a lot of PUFAs that seem really bad, and the article Bruce cited did not control for this factor."
The studies you cited did not control carbohydrate intake. So look at the data again. You mentioned one study feeding the subjects a meal of sausage, eggs, and hash browns. Maybe that meal would be perfectly healthy if you got rid of the hash browns and cooked the meat in coconut oil rather than what ever high-PUFA vegetable oil they probably used.
You always say that we need to consider other factors in the diet, but you seem unwilling to consider the carbs (esp high glycemic carbs, like potatoes, grains, and sugar). We need to isolate carbs from fats, because it might just be that that combination that is bad. It might be more complex, like type of carbs and fats, whether they are refined, and so forth.
We can't conclude that sausage and eggs are a bad meal, when the study also included hash browns, which may have been fried in who knows what. We can only say that such a meal - as a whole - seems to be bad. You are drawing very broad conclusions that often seem unwarranted.
It's true that people are eating more PUFA vegetable oils in today's world than they did 100 years ago. It's also true they are eating more refined sugar, white flour, grains, etc. They are eating less meat, less eggs, less butter, etc. Any one of these factors could be involved, but you blame it all on meat being cooked. Where is the proof that cooked meat is bad, that isolates it from the carbohydrates, Hans? |
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| What do you think about raw fish (sushi), is it better than cooked meat and how much is the DHA/EPA in the whole meat context dangerous compared to e.g. pork fried in canola oil? |
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Bruce,
If there is hash browns fried in a vegetable oil how could you say that it was the carbs in it and not the vegetable oil in it? Carbohydrates are undeniably the primary and preferred source of fuel for the body's mucles and brain. The brain does not like to use fat or its metabolites for fuel.
I do not agree that carbohydrates cause health problems other then the gastrointestinal problems that complex carbohydrates like beans and whole grain breads can cause. But lets say that they can, in theory, its effects will pale in comparison to those of oxidise cholesterol and PUFA metabolites. Everytime I read a study talking about a gene "causing" this disease or that disease I go to my research on PUFA metabolites. It is true that many genes can "cause" disease, but only under certain circumstances. Arachdonic Acid and its metabolites (PGE2, etc) all cause "gene expression" and cause these negative genes to be expressed.
So while carbohydrates might raise the blood sugar and cause spikes in insulin levels, it is the damage caused by PUFAs that causes the actual problem. Its similar to how statin drugs reduce the risk of heart disease. By inhibiting cholesterol production they reduce the amount of cholesterol that can be oxidised, this therefore lowers the risk of heart disease. What many people fail to realise though is that oxidation of PUFAs and cholesterol is the real problem and that avoidance of these two things will reduce their risk of disease much easier and much cheaper then any drugs.
We say that cooked meat is a problem, because it is a fact. It is not THE only problem, but it is one of them. Cooking meat causes the cholesterol in it to oxidise which is nearly as bad as the oxidation of unsaturated fatty acids. I disagree with HSWC when he says that boiling meat is not an alternative to other cooking methods. |
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Taka, I don't eat any fish regularly except lean fish/shellfish. Examples: cod, pollock, perch, tilapia, whiting, crab, tuna, scallops, lobster, oysters, squid, eel, etc. I don't eat things with canola oil, soybean oil, safflower oil, corn oil, rapeseed oil, cottonseed oil, peanut oil, flaxseed oil, etc.
Jamie, I don't know what type of vegetable oil they used to fry the food in the study, but I think the combination of omega-6 and high-carb is dangerous, because too much carbs cause small dense LDL and the omega-6 cause the LDL to oxidize more readily.
There is all sorts of evidence that carbohydrates (esp refined ones) cause health problems. Read Gary Taubes book. Also Weston Price. When people switched from primitive diets to modern diets with refined sugar and white flour, they suffered all kinds of chronic diseases. We can't write all these off as a result of PUFAs, since they were not all using them.
The effects of oxidized cholesterol won't occur on a low-carb diet, because the LDL cholesterol will be large and fluffy, not small and dense. So, even if you eat more PUFAs from pork and fish and so forth, it won't cause heart disease. When we combine carbs and omega-6 vegetable oils, that is a deadly mix. I think we can all agree on that.
Insulin causes damage to the body. Read Ron Rosedale for more information: "Insulin and its Metabolic Effects." I think he mentions one study where they injected insulin into dogs, and they rapidly developed severe atherosclerosis. Insulin does not do good things for your body, esp if you are eating frequent meals exposing yourself to it. If you ate 3 meals or less, with no snacking, like HSWC, it might be OK.
I don't believe that cooked meat is a problem. Those claims seem to be based on epidemiology, not actal science using humans. We need to isolate carbs in the diet from the meat. You can't blame the meat when there were also carbs. If the sausage and eggs by themselves cause the same problem, then we could say those are bad. Otherwise, you could only blame the meal as a whole, with carbs and oils.
There is oxidized cholesterol in butter, cheese, yogurt, etc. I am not going to cut the sides off butter, to avoid those small traces. Also, I think hard fats won't oxidize as fast, because chemical reactions are slowed down. If you want to boil your meat, that's your choice. I just say that the carbs might be a part of the problem. We need very little glucose and we can make glucose from protein and fat any way.
Please search for gluconeogenesis. |
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Jamie, I don't see how you can say what the muscles and the brain "prefer" or what the brain "does not like." If people have tried low-carb diets and seen benefits (physical or mental), it would be a direct refutation of that theory. Maybe for some, a high-carb diet is best. For others, low-carb is better.
Many doctors have noted that their patients improved on low carb diets, like Wolfgang Lutz, Michael and Mary Eades, Jan Kwasniewski, Robert Atkins, etc. Lutz claims to have treated many digestive problems, like the kind HSWC describes, by using a high-fat, low-carbohydrate (72 grams) diet.
Dr. Richard Veech has said the brain runs better on ketones and that they reduce the production of free radicals. He calls ketones "magic" and says the heart and brain operate more efficiently on ketones than glucose. The brain runs on what it is given, and there are redundant energy systems.
http://wilstar.com/lowcarb/bigfatlie.htm |
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What do you think about cooking meat in the Pressure cooker? It's hermeticaly sealed so should not oxidize and also water is present so nothing gets burned to create HCAs? This is different from steaming when large amount of air gets in contact with the meat to oxidize it ... Looks to me like the perfect way of cooking e.g. beef (similar to boiling the eggs which are also closed not to oxidize).
http://en.wikipedia.org/wiki/Pressure_cooker |
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| Why don't you try an experiment? All you need to do is to leave a small piece of meat out on a dish overnight, and smell it and taste it every several hours. Try the same meat but different cooking techniques. This should give you a general idea. You can also do this with different oils. Comparing how fast the oils start to get an "off" or rancid taste or smell to the meat should be interesting. I don't eat meat and I only have butter and coconut oil, so I haven't done this type of experiment yet. |
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This was posted by someone else on another newsgroup:
"Turkey meat and water"
"Malondialdehyde (MDA) levels nearly quintupled"
Federation of American Societies for Experimental Biology
New discovery could reduce the health risk of high-fat foods
January 14th, 2008
Federation of American Societies for Experimental Biology
(NewsRx.com) -- Just as additives help gasoline burn cleaner, a
research report published in the January 2008 print issue of The FASEB
Journal shows that the food industry could take a similar approach
toward reducing health risks associated with fatty foods. These "meal
additives" would be based on work of Israeli researchers who
discovered that consuming polyphenols (natural compounds in red wine,
fruits, and vegetables) simultaneously with high-fat foods may reduce
health risks associated with these foods.
"We suggest a new hypothesis to explain polyphenols," said Joseph
Kanner, senior author of the report. "For the first time, these
compounds were demonstrated to prevent significantly the appearance of
toxic food derivative compounds in human plasma."
For the study, six men and four women were fed three different meals
consisting of dark meat turkey cutlets. One meal, the control,
consisted of turkey meat and water. The second meal consisted of
turkey meat with polyphenols added after cooking (one tablespoon of
concentrated wine) followed with a glass of red wine (about 7 ounces).
The third meal consisted of turkey meat with polyphenols added before
cooking and then followed by a glass of wine.
At various points during the study, researchers took blood and urine
samples to measure levels of malondialdehyde (MDA), a natural
byproduct of fat digestion known to increase the risk for heart
disease and other chronic conditions. The researchers found that MDA
levels nearly quintupled after the control meal, while MDA was nearly
eliminated after subjects consumed the meals with polyphenols.
"As long as deep fried candy bars are on menus, scientists will need
to keep serving up new ways to prevent the cellular damage caused by
these very tasty treats," said Gerald Weissmann, MD, Editor-in-Chief
of The FASEB Journal. "This study suggests that the time will come
where people can eat french fries without plugging their arteries."
Keywords: Federation of American Societies for Experimental Biology.
This article was prepared by NewsRx editors from staff and other
reports. Copyright 2008, NewsRx.com. |
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QUOTE: Men who eat a diet low in fat and red meat but high in vegetables and lean protein and who drink alcohol in moderation may not just be doing their hearts a favor. A new study shows that such a heart-healthy diet may also be good for the prostate... UNQUOTE.
Source: http://www.sciencedaily.com/releases/2008/02/080213102841.htm
Of course, by "high fat" diet, they really mean a historically high PUFA diet, but they aren't being as precise as they should be, for whatever reason. |
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Is it true that meat (particularly, red meat) has lot of arachidonic acid ? Have I to be afraid not to be able to become EFAD if I eat sometimes meat ?
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| This message has been deleted by the manager or assistant manager. |
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| The main danger of AA is when it's in your cells, because then it gets released upon any minor stress and can cause mayhem. It's so unstable that even a light cooking of meat would probably destroy most of it. You don't want to be truly "EFAD," just free of AA with Mead acid replacing it. True "EFAD" would mean that your body would have trouble making enough Mead acid to meet demands. I don't eat meat (only small amounts of gelatin), but I don't think it's something you have to worry too much about in this context, so long as you don't eat way too much of it. |
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