Estrogens in Cooked Meat

We’ve known since 1939 that there were “cancer-producing substances” in roasted meat. Scientists have since identified these compounds as heterocyclic amines, 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….”

As I describe in my 2-min. video Carcinogens in Roasted Chicken, studies on rodents have historically downplayed the risk, suggesting 99% of these chemicals can be removed by the liver. Humans, it turns out, are actually 50 times less able to detoxify these carcinogens, however, which may explain why studies done on Long Island and around the world have shown women eating more broiled, grilled, fried, barbequed, and smoked meats appear to have up to five times the risk of developing breast cancer (see also Muscle Tremors & Diet and Fast Food Tested for Carcinogens).

More than 85% 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 in cooked meat like PhIP are considered “three strikes” carcinogens because they are not only DNA-damaging mutagens and promote cancer growth, but also increase its metastatic potential by increasing tumor invasiveness.

Strike 1: By asking women undergoing breast reduction surgery 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 these cooked meat carcinogens.

Strike 2: In my 4-min. video Estrogenic Cooked Meat Carcinogens I show that not only may these meat chemicals trigger the original cancer-causing mutation, they may also then promote the growth of the tumor. PhIP for example activates 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 of breast cancer.

Strike 3: Click on the video pick above to see what affect these cooked meat carcinogens may have on the invasiveness and metastatic potential of human breast cancer. The growth hormone IGF-1 may also promote tumor progression and invasion (see IGF-1 as One-Stop Cancer Shop). IGF-1 is released by our liver in response to animal protein consumption regardless of how it’s cooked (why? See Higher Quality May Mean Higher Risk.) On the other hand, broccoli and Indian gooseberries may have both anti-proliferative and anti-invasive properties: Lung Cancer Metastases and Broccoli and Amla Versus Cancer Cell Invasion.

Most of the experiments on the cancer-causing effects of cooked meat chemicals were done on breast cells in a petri dish, though. 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 none was detected in her breast milk.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 year-in-review presentation Uprooting the Leading Causes of Death.

Adapted from Kathy Freston’s excellent post Anti-Breast Cancer: The ‘Three Strikes’ Carcinogen to Avoid

Image credit: jefferyloo / Flickr

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William C
William C1 years ago


W. C
W. C1 years ago

Thank you.

J.L. A.
JL A5 years ago

good to know

Elena T.
Elena Poensgen5 years ago

Thank you :)

Dale O.

Ala M. says that we should: "Take out all the chemicals and hormones out of our meat diet and we will not develop any breast cancer. The Natives ate fresh grilled and barbequed meat and had no cancer."

What a novel concept! Nothing quite like common sense. Meat as it should be! Organic and safe. Same goes for veggies without the GMO and pesticides. Natural eating does wonders, along with exercise and proper portion sizes.

Jennifer C.
Past Member 5 years ago

Thank you.

Edgar Zuim
Edgar Zuim5 years ago

Very disturbing, but it's good to know.

Lydia Price

So tragic...they murder animals for food, murder mice to test it, and now murder humans who consume it. Death begets death. Beget kindness instead.

Sue H.
.5 years ago

All my older relatives lived into their 80's and fried or roasted all their meats, none had breast cancer. Back then we fried or roasted with the fat that came off the bacon we had for breakfast. I do not think our food supply is as safe today. I put a beef roast in the pan with a lid and 15 minutes later it is sitting in 1/4 inch of water that had been injected into the meat. When cooked it is half the size it was before putting it in the pan. All that water comes out of the meat and that never used to happen when I was a child.

Barbara D.
Past Member 5 years ago

I only eat meat rarely and what I do eat comes from local farms so I know what I'm getting and how the animals are raised. No factory-farm meat for me!