You may have heard a lot recently about how a chemical that is formed from cooking meat is carcinogenic (cancer-causing), but recent studies show that the scope of what's bad for you in terms of meat is actually expanding.
We've known since 1939 that there were "cancer-producing substances" in roasted meat. Scientists have since identified the compounds as heterocyclic amines. I know... what the? Well, they're described by the National Cancer Institute as "chemicals formed when muscle meat, including beef, pork, fish, and poultry, is cooked using high-temperature methods, such as pan frying or grilling..." Historically, studies on rodents downplayed the risk, suggesting 99 percent of these chemicals can be removed by the liver, but it turns out we're not rats! Humans are 50 times less able to detoxify these carcinogens, which may explain why studies done on Long Island and around the world have shown that women eating more broiled, grilled, fried, barbecued, and smoked meats appear to have up to 400 percent higher risk of developing breast cancer. (I think of all the chicken I broiled or grilled through the years so as not to get too much fat on my plate!)
According to one study:
More than 85 percent of breast cancers are sporadic and attributable to long-term exposure to environmental carcinogens, such as those in the diet, through a multistep disease process progressing from non-cancerous to premalignant and malignant stages.
Most cancer-causing agents are involved in either the initiation stage of cancer, triggering the initial DNA mutation (like radiation), or the promotion stage of cancer, promoting the growth of the tumor (certain hormones like IGF-1). But heterocyclic amines like one called PhIP found in cooked meat have been called "three strikes" carcinogens because they cause DNA mutations (strike one), and they promote cancer growth (strike two), and they also increase its metastatic potential by increasing cancer invasiveness (strike three).
By asking women undergoing breast reduction surgery (one way to look at breast tissue from a wide variety of women) about their meat cooking methods, researchers were able to directly correlate the number of DNA mutations found in breast tissue with the estimated dietary intake of cooked meat carcinogens. The DNA-damaging effects of these carcinogens have been known for over a decade. What surprised scientists and doctors was that not only may these meat chemicals trigger the original cancer-causing mutation, they may also then promote and spread the growth of the tumor, as PhIP was subsequently found to activate estrogen receptors on human breast cancer cells almost as powerfully as pure estrogen! Even at very low doses, the cooked meat chemical PhIP appears to drive the growth and spread of breast cancer, strikes two and three.
Putting it all together, researchers recently demonstrated for the first time that normal breast cells could be transformed completely into breast cancer just by dripping PhIP (at the levels found in cooked meats) on normal human breast cells. That's all it took, and Jekyll becomes Hyde.
PhIP is also found in cigarette smoke, diesel fumes, and incinerator ash, but the highest levels in food are found in fried bacon, fish, and chicken. Even just baking chicken at around 350 degrees for 15 minutes leads to significant production of PhIP. If you are like me and thought that it was just those blackened bits of meat from the grill that were the problem, this might come as a rude awakening.
Granted, these were breast cells in a petri dish. How do we know these carcinogens make it not only into the breast after you eat cooked meat, but into the breast ducts, where most breast cancers arise -- so-called ductal carcinoma? Researchers didn't know for sure, until a study out of Canada measured the levels of PhIP in the breast milk formed in those ducts of nonsmoking women. The average concentration of the "three strikes carcinogen" they found in the breast milk of meat-eating women corresponded to significant cancer growth activation. One of the women was vegetarian, though, and interestingly none was detected in her breast milk. None.
Toxicologists lament that: "Exposure to PhIP is difficult to avoid because of its presence in many commonly consumed cooked meats, particularly chicken, beef and fish." But if you're able to somehow dodge those meats (and don't suck on a cigarette, tailpipe, or incinerator smokestack) maybe it's not so difficult to avoid after all. Just move away from the Standard American Diet of meat/chicken/fish as the centerpiece of your meal and lean toward whole grains, beans and legumes, nuts, fruits, and veggies.
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