Doctor's Note

This is the first of my four-part video series on heterocyclic amines, those DNA-damaging chemicals formed in cigarette smoke, and when mammal, bird, and fish muscles are cooked. I’ve covered them previously in Muscle Tremors & Diet; Fast Food Tested for Carcinogens; and Carcinogens in Roasted Chicken?

Carcinogens tend to either initiate, or promote cancer—rarely both. Not only may heterocyclic amines trigger the original mutation, and help the tumor grow; they may also aggravate cancer invasiveness—which I cover in PhIP: The Three Strikes Breast Carcinogen.

Also, be sure to check out my associated blog posts for more context: Mushrooms for Breast Cancer PreventionEstrogenic Chemicals in MeatAvoiding Cooked Meat CarcinogensFoods that May Block Cancer FormationShould We Avoid Titanium Dioxide? and Breast Cancer & Alcohol: How Much is Safe?

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  • Jo

    Thank you Dr. Greger!

  • HemoDynamic, M.D.

    You make it so much easier to not only walk uphill, but run uphill with you heading the charge.
    What are we UP against? Big Pharma, Big Ag, and Big Business with Greed ruling the whole bunch!

    • Jamal

      Oh shut the fuck up will you

  • Catherine J Frompovich

    Dr. Greger,
    As a natural nutritionist I must say you are doing a fantastic job in educating about how food works in the body, something medicine has ignored for so long.
    Thank you very much for your excellent work, most impressive and informative, easily understood food facts at

  • Is there any similar data for phip effect in men, either in breast or prostate tissue, and if so, does it (like it does for women) correlate with the temperature at which meat is cooked or charring?

    • Rph1978

      There are few studies done on Phips and prostate cancer in
      men. The study by Amanda J. Cross 2005 showed that consumption of very well done meat (>10 grams daily) increased the risk for prostate cancer. Out of all the heterocyclic amines, Phips tends to be one of the most readily absorbed into the body. The mechanism of mutagenicity is similar to that found in breast tissue, where it exhibits estrogenic activity and increases formation of DNA adducts. Cooking meat at high temperature until it’s well done increases Phips formation but not very many people cook their steak that way. The study also mentions that greater Phips intake can occur when consuming less well done meat but more frequently.
      Microwaving, boiling, and steaming produces very low levels
      of HCA’s whereas using fats and oils to cook meat greatly increases HCA formation. A study by Cynthia P. Salmon (2000), suggests cooking meat at lower temperature with frequent turning over can lower the amount of Phips formed.

      1. Amanda J. Cross, Ulrike Peters, Victoria A. Kirsh, et al., A Prospective Study of Meat and Meat Mutagens and Risk, Cancer Res 2005;65:11779-11784
      2. Saida Robbana-Barnat, Maurice Rabache,Emmanuelle Rialland, and Jacques Fradin, Heterocyclic Amines: Occurrence and Prevention in Cooked Food, Volume 104, Number 3, March 1996 * Environmental Health Perspectives
      3. Cynthia P. Salmon, Mark G. Knize, Frances N. Panteleakos, Rebekah W. Wu, David O. Nelson and James S. Felton, Minimization of Heterocyclic Amines and Thermal Inactivation of Escherichia
      coli in Fried Ground Beef, JNCI J Natl Cancer Inst (2000) 92 (21): 1773-1778.

      • Thanks for the research.

        However, not hugely convincing (in men): your reference #1: “the highest quintile of PhIP was associated with a 1.2-fold increased risk of prostate cancer”…not nearly as shocking as in women.

        “More than 10 g/d of very well done meat, compared with no consumption, was associated with a 1.4-fold increased risk of prostate cancer. Total, red, or white meat intake was not associated with prostate cancer risk.”

        Most men are not vegetarians…best advice is to not eat the burned tips, but that eating meat by itself, even well done meat, does not raise prostate CA risk. I think colorectal cancer may be more of an issue.

        I advise people to use Mediterranean marinades to reduce HCAs and PhIP…with rosemary, the marinades drop HCA production by 87%: one study:

      • PandaB

        Denial isn’t a river in Egypt…

      • Very nice succinct summary. Thank you.

        A diet high in red meat has also been associated with an elevated
        risk of colorectal, lung, esophageal and liver cancer. At least according to food frequency recall questionnaires, which as you know, are not an optimal method for testing hypotheses (IMO, this sort of epidemiologic research generates them, rather than tests them)

        I think the goal is to make meat eating safer, healthier, smarter, more flavorful: I think those positive associations will work better than finger-shaking in cancer prevention.

        However, the estrogenic activity of HCAs is interesting to me, and the conflicting studies on prostate CA make me wonder…are there estrogenic effects of HCAs or PAHs in men?

      • Twinkle

        RPH1978 thanks for that info… I am particularly interested in this line: “Microwaving, boiling, and steaming produces very low levels of HCA’s whereas using fats and oils to cook meat greatly increases HCA formation.” First, may I please ask, what was the source(s) for the info about levels of HCA from MICROWAVING… and when you wrote that “using fats and oils to cook meat greatly increases HCA formation” were you referring only to frying and deep frying, like on a stove — OR if (for example) fish or chicken were MICROWAVED in a sauce containing some (e.g.) olive oil, would that inclusion of a fat also markedly increase HCA formation, even though the meat was being MICROWAVED? And 2nd, have you seen anything about the levels of HCA that are formed when TURKEY is cooked? For years we were warned that red meats are more harmful/ risky than white meats… so I was startled to see that studies show that the worst levels of HCA formation happen when chicken and fish are cooked… so I am wondering about TURKEY- for example, I was thinking that the sliced “organic roasted turkey breast” I have been buying was (relatively) safe… but that was before I read about the HCA levels in cooked chicken… have you seen anything about HCA levels in TURKEY? (1st question is about MICROWAVING, 2nd question is about TURKEY.) Thanks!

        • Rph1978

          One thing I’ve come across is that studies are inconsistent and variable. For example, marinating meat (chicken,beef, pork) prior to cooking can reduce heterocyclic amine (HCA) formation regardless of the cooking method. In addition, tumeric-garlic and teriyaki marinades showed decreases in HCA whereas honey based marinade showed an increase in HCA. This may not be surprising since glucose in honey is a precursor to HCA in small amounts whereas excess amount of glucose added to meat prior to cooking appears to inhibit HCA. Food Chem Toxicol 30:681-688 (1992).On the other hand, there was no reduction in HCA formation in marinated or non-marinated salmon. So it seems to depend on the type of meat and marinade. (Journal of Food Compost Anal. 2010 February 1; 23(1): 61–69) Microwaving beef for 1, 1.5, 2 or 3 min before frying at either 200 degrees C or 250 degrees C for 6 min per side has been shown to reduce heterocyclic aromatic amine precursors (creatine, creatinine, amino acids, glucose). Food Chem Toxicol. 1994 Oct;32(10):897-903. Creatine in muscle meat seems to be an important precursor to the formation of HCA where creatine forms part of the phips molecule.
          I should clarify that certain fats such as butter and rapeseed oil (after frying of beef) can increase HCA whereas other fats such as sunflower seed oil and margarine has been shown to reduce HCA and this was explained by the fact that these oil contain antioxidants such as vitamin A and E. (Food Chem Toxicol. 1995 Dec;33(12):993-1004 The same was found with olive oil (Food Chem Toxicol. 2003;41(11):1587-1597) when burgers where fried in the oil there was less HCA. Again, this was thought to be due to the polyphenol content of olive oil. Other studies have shown that adding garlic,
          onions, dried plum and even cherries to the beef patties resulted in less HCA after cooking. (Natural Medicine Journal 7/1/2010) Since turkey is similar to chicken,
          any meat cooked at high temperature increases the HCA content. One study (Meat Science 85 (2010) 149–154) showed that roasted chicken and duck meat formed
          significantly lower HCA than pan-fried, grilled or deep fried meat.

    • Grace

      Hello John – In the excellent Book “On food and Cooking-The Science and Lore of the Kitchen” by Harold McGee he states page 187: “Certain cooking processes transform the proteins and related molecules in meat and fish into highly reactive products that damage DNA and may thereby initate the development of cancers. So the rule for cooking meat also holds for cooking fish: to minimize the creation of potential carcinogens; steam, braise and poach fish rather than grilling,broiling or frying it.” He adds: ” If you do use high heat, then consider applying a marinade whose moisture, acidity and other chemical qualities reduce carcinogen production.” On page 124 he talks about the actual chemicals involved in the cooking of meats. This is a well researched book and as a nutritionist advising cancer patients; I find it invaluable. Grace

      • Hi, Grace: yes, McGee’s books are terrific. Shirley Corriher’s are too.

        Several marinades, however, have been tested and been shown to reduce HCA formation in the meat by up to 87% (I cover them in my blog and ChefMD book).

        This is still different (though worthwhile) than an increase in actual cancers in men who eat high temperature grilled/cooked meats: that’s what I’m curious about.

        • Terry Silberstein

          Why not just stop eating animal meat? I don’t get all the work arounds. Stopping meat consumption is clearly better for us, the animals and the planet – I don’t “get” why we continue to fight this obvious fact so we can continue to eat something that is completely unsustainable to the health and well being of the home we all share. I “get” it seems hard, but it will be harder in 50 years for all the people coming after us that have to live in an increasingly un-inhabitable place.

  • Wow, the power of the information in your video summaries on current nutritional/health science never ceases to amaze me. The information you share with us, gives me hope that we can improve our health without invasive or expensive interventions. Thank you!

  • @davestimes

    Hi Dr Greger! Can I start by saying thank you for the great information you share. Can you please help? My sister has Urachal carcinoma in her Lungs! The Doctors are running out of ideas and the treatments have helped but are becoming Ineffective. Can you please offer any advice?

    • Nancy H

      Hi @davestimes, I am very sorry to hear of your sister’s prognosis.

      Have you heard of Bob Wright, the Director of the American Anti-Cancer Institute? He’s got some great insight into beating cancer: Please let me know if this is helpful to you —

      ~All the best.

    • Grace

      Hi @davestimes…I am director of a cancer Institute in Australia and I host a US based show called navigating the cancer maze on Voice America. I strongly suggest you look at Hallwang private oncology clinic in germany and prof Thomas Vogl. Best of luck to you and your sister. Grace Gawler

  • Robyn Tait

    Love your videos Doc–this one may however may require a little more translation for some of us!

  • Dr. Greger – this is interesting, but I am wondering whether you are aware of any studies indicating that women who have eaten a vegetarian/vegan diet most of their lives are, if unfortunate enough to develop breast cancer, more likely to be diagnosed with the more aggressive triple negative breast cancer which is not affected by estrogen?

    • Grace

      I have worked in the area of cancer for almost 40 years, pioneering the first edcative support groups in Australia & I’ve worked with around 15,000 patients globally. The majority of people who have sort or seek my services have been leading good lifestyles, many vegertarians, vegans, those who ate meat in moderation; juicing advocates, raw food avocates, sports people. My patients were not obese, most did not drink alcohol and were not smokers. The majority of breast cancer patients I see are hormone receptive. There certainly is an increase in the diagnosis of triple negative breast cancers – but in my demograhic of several thousand Breast cancer patients – there does not appear to be a link with diet that everyone reports in the research… My patients get personalised care and complete surveys that allows us to see a lot of lifestyle information pre cancer. There is certainly more to this than meets the eye!

  • Roby Sherman , MD

    Can you give us some information about the relationship of so-called clean fish and feta cheese and eggs to breast cancer progression or aggressiveness? ( in a post menopausal woman)

  • Roby Sherman , MD

    What about Protocell for breast cancer in a post menopausal woman?

    • Hi Roby,

      Is this for you or for a patient? If it’s for you, I’m so sorry to hear of your diagnosis. My husband was diagnosed with colorectal cancer this past year and we also looked into Protocel, after reading a detailed account of it in the book, Outsmart Your Cancer by Tanya Harter Pierce. However, after searching PubMed and consulting with cancer researcher Ralph Moss, PhD at, we found that there are no scientific studies on this alternative treatment. Dr. Moss advised against taking it as there are other alternative treatments that can be an effective adjunct to traditional treatment that have studies to support their success.

      We have many videos on diet and breast cancer here:

      I suggest an integrative approach, utilizing the best of western medicine, along with a whole food plant-based diet with the addition of hibiscus, white or green tea, cooked mushrooms and herbs and spices (India has one of the lowest rates of breast cancer in the world), along wtih exercise and plenty of love and support, rest and relaxation and some kind of spriritual practice and/or meditation, I recommend the books, Radical Remission by Kelly Turner, PhD and Love and Survival by Dean Ornish, MD.

      My mom had stage I breast cancer just three years ago. She had surgery and she and my dad have been following a plant-based diet ever since and loving it. All her scans have been fine.

      Everyone’s journey is different, but a whole food plant-based diet is one essential tool in your tool belt in fighting cancer. While I have read of a few people online with testimonials who have had success with Protocel, there are no scientific studies for it at this time, so I cannot recommend it.

      Thanks so much for the question.


  • Southlander

    My education continues. With “thanks” and “appreciation”. Don and I CAN! :-))

  • DStack

    For years I’ve been wishing a site like this existed and only just now have I discovered it. Thank you for all your work! I’m sharing this site with everyone I know. I myself have a lot of catching up to do!

  • Barbara Barker

    I am speechless as to how poisonous our food supply is, I try hard to eat healthy, and I consume a lot of baked chicken. Now I will have to substitute it with something else. I’ve always been somewhat heatlh conscious, as they say knowledge is power and I pay more attention now that I am 50 and in good health. I try to read a lot about our food supply and how I can stay as healthy as I possibly can, but I’ve stumbled on to some pretty disturbing information and finding out more and more everyday.

  • disqus_pv774DfEEq

    a person I know(non-smoker) ended up with breast cancer within 2 years of going on a diet which mainly consisted of animal protein, and avoiding carbs including fruit and vegetables.
    I do wonder if it was to do with the diet, whether or not it helped the cancer to spread.