I think the logical follow-ups to this study are to:
A: look at actual impacts of blood concentrations of the offending substances following a meal of cooked meat, and B
B: look at varying the degree/intensity of cooking and determine its impact on the formation of these products.
The study shows a particular response to a particular chemical - okay. However, to support their conclusion, they need to demonstrate that certain actions do produce the claimed increase in blood levels of the suspect chemical.
(I'm not disagreeing with the original post in this thread - in fact, I suspect that the negative effects that data sometimes show to be associated with meat eating, are not the direct product of meat itself, but perhaps iron overload and/or overcooking)
And vegetables and fruits are anti-oxidants. A balance is created in eating a well rounded diet of meat, roots/tubers, fruits, and occasional nuts/seeds.
You can't totally get caught up in nutritionism and lose sight of what is good for you.
Cooking and even charring meat leads to a very large variety of compounds (which change based on temperature, method of cooking, holding time, holding temp, reheating methods). Some of these are carcinogenic, some are anti-carcinogenic. Unless you're some lame molecular gastronomy purist you consume all of these complex compounds at the same time, [B]not[/B] in isolation. This is just like most of those "damning" studies on dairy which focus on the terrible effects of high consumption of isolated casein when there are just as many studies showing the protective effects of whey protein.
I slow cook meat in the crock pot on medium for hrs, all day really.
On the gas grill, I set it at 300 and cook chicken breasts and ribs for a long time.
Steaks a different story, short time, but still never on high temps.
Inside, on a Bosch glass cooktop, I get the pan hot on maybe 8, then cook never higher than 4.
[QUOTE=Nekron;868011]Ehm no it doesnt. [/QUOTE]
"During the cooking of meat, mutagenic and carcinogenic heterocyclic amines are formed"
[QUOTE=wiltondeportes;870439]You can't totally get caught up in nutritionism and lose sight of what is good for you.[/QUOTE]
I'm interested in the truth and then how to act on it. Lets suppose that eating meat regularly does increase the risk of cancer significantly, then its not really good for you is it. So then am I going to bury my head in the sand and pretend its bad science like anybody who is invested in dogma? Will I just accept the consequences, and continue eating lots of meat, due to the convenience and taste? Will I reduce the meat I consume or cook it less?
Yeah I feel ya, man, it is frustrating to get no definitive answers on a potentially scary question. I will save ya with research.
There have been numerous experiments and controlled trials to try to figure out exactly how much DNA damage harshly cooked red meat could cause to the colon and thus cause cancer. It also has potentially harmful effects on the rest of the body, but the colon is kind of the area that gets hit the hardest so that's the one that has been studied the most. There are many positive epidemiological studies, and then there are some that are negative. Controlling for cooking intensity usually modifies risk like this one that found no association with baked and boiled meat [URL="http://www.ncbi.nlm.nih.gov/pubmed/15474875"]Meat cooking habits and risk of colorectal cancer ... [Nutrition. 2004] - PubMed - NCBI[/URL]. There are even some like a recent one where lightly cooked meats (baking) were inversely associated, probably due to the CLA and carnosine content of grass-fed meat in Australia. So it is likely the case that cooking intensity matters. [URL="http://www.ncbi.nlm.nih.gov/pubmed/21364608"]Meat consumption and cooking practices and t... [Eur J Clin Nutr. 2011] - PubMed - NCBI[/URL]
I have read the rat and human experiments and they tell us quite a bit. I don't think that they either implicate or fully exonerate meat, but they do implicate high heat cooking and nutrient-poor diets. I thus worry about low carbers eating mostly meat and cooking it harshly (classic Atkins anyone? I think they have cleaned up their act since, though).
[URL="http://www.ncbi.nlm.nih.gov/pubmed/21541030"]Inhibition of fried meat-induced colorectal DNA dam... [PLoS One. 2011] - PubMed - NCBI[/URL] <----important study
In this one they compared harshly cooked meat (fried at 250 degrees celsius or 482 F ) to lightly cooked meat (100 degrees C 212 F) in rats to see how carcinogenic they were. The high heat one was quite carcinogenic whereas the low heat one was not at all. They also tried adding in some inhibitors, things that will counteract the carcinogens, they tested green vegetables, yogurt, etc. That mitigated the effect partially but at the end high heat was still bad. I wish they had done another group with a temperature in between those but we can use the lower heat measure as a starting point. Then follow the lower temperature, less harsh techniques to have the greatest confidence that we aren't producing anything harmful. Pressure cooking and baking are probably safe.
There is also much potential to inhibit the process of the formation of mutagens and neutralize them inside the body. Green tea with the meal (or any other type of tea for that matter) is powerfully protective [URL="http://www.ncbi.nlm.nih.gov/pubmed/10202396"]Cancer chemopreventive mechanisms of t... [Proc Soc Exp Biol Med. 1999] - PubMed - NCBI[/URL]
Using marinades made with red wine or spices is protective. [URL="http://www.ncbi.nlm.nih.gov/pubmed/22642699"]Inhibitory effect of antioxidant-rich mari... [J Agric Food Chem. 2012] - PubMed - NCBI[/URL]
There is another issue with high heat cooking, that of cholesterol oxidation products. Cholesterol becomes oxidized and gets into the blood stream depending on leakiness of the gut, and then it can damage the arteries. This is easily inhibited by anything rich in antioxidant flavanoids like red wine or green tea. [URL="http://www.ncbi.nlm.nih.gov/pubmed/20923702"]Proinflammatory effect of cholesterol an... [Free Radic Biol Med. 2010] - PubMed - NCBI[/URL] [URL="http://www.ncbi.nlm.nih.gov/pubmed/21294933"]Red wine prevents the postprandial increase in pla... [Br J Nutr. 2011] - PubMed - NCBI[/URL] Probably spices and probably vegetables and fruits
There is another issue with meat and that is haem iron. It can oxidize and cause colon cells to proliferate, damaging their DNA like the HCA's do. This is prevented by calcium in the diet, as it is needed to bind haem and remove it from the colon when it doesn't get absorbed [URL="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3311222/?tool=pubmed"]Calcium carbonate suppresses haem toxicity markers without calcium phosphate side effects on colon carcinogenesis[/URL] Also vitamin e, and fiber prevents damage to the colon by cooked red meat due to butyrate production [URL="http://www.ncbi.nlm.nih.gov/pubmed?term=red%20meat%20mouse%20resistant%20starch"]Inhibition by resistant starch of re... [Cancer Prev Res (Phila). 2011] - PubMed - NCBI[/URL]
Indeed, with all of this good news about a normal healthy diet protecting the body there have been studies where red meat intake did not harm humans [URL="http://www.ncbi.nlm.nih.gov/pubmed/20728565"]High-protein/high red meat and high-carbohydrate w... [Mutat Res. 2010] - PubMed - NCBI[/URL] and some that even show less DNA damage in a red meat containing diet than a similar but meatless vegetarian diet [URL="http://www.ncbi.nlm.nih.gov/pubmed/19498009"]Effect of processed and red meat on endogenou... [Carcinogenesis. 2009] - PubMed - NCBI[/URL] possibly due to the carnosine in red meat that protects the colon [URL="http://thatpaleoguy.com/2011/02/21/carnosine-colons-and-cancer/"]Carnosine, Colons, and Cancer | THAT PALEO GUY[/URL] Although clearly if you cook it really harshly you have a net loss. There was one that showed more damage in the red meat group, but it looked to be nearly devoid of good antioxidants, and calcium, and is contradicted by the former two.
I also suspect that endogenous defenses will be better in people with higher glutathione and other antioxidant enzyme levels, and in people with lower inflammation. For example whey, a good glutathione booster, is protective against tumorigenesis [URL]http://www.ncbi.nlm.nih.gov/pubmed/7722681[/URL]
So in summary, meat does not have to be harmful by itself. Many antioxidant containing foods are powerfully protective, fiber is good, calcium is needed for a non-cooking related potential danger.
Someone who is eating a diet like Mark Sisson recommends is not likely to be at an increased risk, in fact probably a decreased risk due to their red meat consumption.
Ain't skeered! Been eating lots of well cooked, even sometimes crispy meat all my life along with plenty of fruits and veggies. Had my colonoscopy at 50 and had no polyps, lesions, diverticuli---nothing. Completely normal. So, pass me another crispy steak, some roasted veggies and a glass of wine!
As I understand it, slow-cooking meats poses a greater risk than cooking quickly at a high temperature. So think of methods like smoking (which leaves the smoke residue which some question as carcinogenic itself to boot) and barbecuing as opposed to, say, cooking meats rapidly in a frying pan over high heats for just a few minutes.
Trick with grilling though, is to not char your meat too much because this is where a lot of the carcinogens are said to come from, though you could debate this. But not charring grilled meat is like impossible for some people to master. ;)
I agree with whoever said that we minimize our risks as much as possible. Yes, cooked meat contains carcinogens. But that doesn't mean that if you eat cooked meat, you are automatically going to get cancer. In fact, given all the research into how cancer cells thrive on glucose makes me wonder if you eat the meat without dessert, you might be OK.
Thanks for the thorough post. Seems the take home points are don't only eat meat, and cook it as low a temperature as you can.