Cancer and Diet
The Latest on Processed Meats, Fats and More

Summary

This event was part of The Dr. Lawrence H. and Roberta Cohn Forums. We are deeply saddened by the loss of Dr. Lawrence H. Cohn, advisor and supporter of this Forum in addition to others in the The Dr. Lawrence H. and Roberta Cohn Forums series.

CANCER AND DIET: The Latest on Processed Meats, Fats and More
Presented in Collaboration with The Huffington Post and in Association with Harvard Health Publications

This Forum explored what we know, and don’t know, about links between diet and cancer. Included in the discussion was the World Health Organization’s classification of processed meat as a “Group 1” carcinogen; the latest on what is known about fats and cancer; and the just-released Dietary Guidelines for Americans as they pertain to cancer and diet. Additionally, the panel discussed cancer prevention strategies.

Brief Video Highlights

Part of: .

Presented in Collaboration with The Huffington Post and in Association with Harvard Health Publications

Background Articles

Image Credit: iStock by Getty Images/Milan Stojanovic

  • april

    Can you watch this online?

    • The Forum Moderator

      Thanks for asking. Yes, the live stream will be on this site starting at 12:30pmET.

  • The Forum Moderator

    Welcome everyone. We will be starting in a few minutes.

  • The Forum Moderator

    Just a few more minutes and we will begin.

  • Hello!

    • The Forum Moderator

      Welcome Erwin.

  • The Forum Moderator

    Our event has begun. You should see the speakers in the video player frame in a few seconds. If not, please refresh your page and hit “play”

  • The Forum Moderator

    This video is courtesy of Huffington Post, which is our media collaborator today.

  • The Forum Moderator

    Dr. Hu served on the U.S. Dietary Guidelines Advisory Committee. The new guidelines were released last week and can be viewed here: http://health.gov/dietaryguidelines/2015/

  • The Forum Moderator

    Dr. Hu provided an assessment of the new guidelines here: http://www.hsph.harvard.edu/news/features/assessing-the-new-u-s-dietary-guidelines/

  • The Forum Moderator

    We will have a brief Q&A at the end of this panel. Post your question here or email them to theforum@hsph.harvard.edu.

  • Research

    Please define “processed meat”

    • The Forum Moderator

      Thanks — great question. I think that Dr. McCullough plans to do so.

    • The Forum Moderator

      Dr. McCullough is defining now. Thanks

  • The Forum Moderator

    Dr. Giovannucci serves as a panelist for the World Cancer Research Fund. That group looks at links between cancer and diet. More information is here: http://www.wcrf.org/

  • Sarah Konkel

    Is there data on the nitrates from the processed meat being more of the issue than the meat itself?

  • Lunecee Eligene

    Question for the panel: Is there a distinction between grass-fed red meat vs. conventional red meat?

  • The Forum Moderator

    This clip is courtesy of ShareWIK.

  • The Forum Moderator

    Thanks all for these great questions. I will pass them along.

  • Katherine Perkins

    I was unlucky enough to be sent off to school in the 60’s and 70’s with a bologna or liverwurst sandwich almost every day. Since my 20’s, I have reduced my processed meat consumption dramatically. Now I eat none. My question is, do we really know how much bearing early nutrition has on the overall picture of cancer risk and how much life style changes can truly “reverse” carninogenic effects of poor choices of earlier years. What biometrics are used to measure lessening of risk after dietary changes?

  • Marlene

    What do you say about lunch meats with no nitrates or preservatives?

  • Kelly Pflaum

    Can the panel discuss the varying diets: standard American vs vegetarian vs vegan? Does one clearly offer improved health outcomes?

  • Sarah Konkel

    The NEJM came out earlier this year stating that glyphosate and GMO crops are “probable carcinogens”. Are there any changes in recommendations to these foods?

  • Sharon

    What is the risk of eating turkey breast cold meat – no preservatives or salt added ? It is “processed”, but not a red meat and no nitrates

    • The Forum Moderator

      Thanks Sharon — I think that your question is being asked now.

  • salbers

    What is the optimal BMI for minimizing exposure to Cancer?

    • Tara

      Is it BMI or overall body composition (e.g. central fat deposits)?

      • salbers

        Both.

  • The Forum Moderator

    Thanks all for your great questions. We’ll get to as many as we can. We also plan to see if any of our panelists can address questions posted here later in case.

  • Hannah Jordan

    Can anyone talk about if diet or other therapies can help someone who has already been diagnosed with cancer (specifically small bowel cancer)?

  • The Forum Moderator

    We will be posting this full-length video on this site over this weekend. Next week, we will post on YouTube and iTunes. The audio also will be posted.

    • Kathy Birkett

      Thank you!

  • Julian Cuevas

    Is a stronger microbiota able to reduce risk of cáncer?

  • Shanti P.

    Why are we still saying that dairy is a good source of calcium Dr. Willett?! When there are studies now showing that calcium from dairy products are not good for long-term health/absorption/depletion? Wondering if there are any non-industry funded calcium studies as of late that indicates the truth. I do think that it’s time to share information about calcium rich plant-based foods and stop marketing dairy as the rich/only/good source in 2016.

  • How about whole foods plant-based diets? That would steer away BOTH from the red meats (as well as from other meats) AND from the sugars and other processed PLANTS (such as sugar) that we think are less health-supporting.

  • The Forum Moderator

    Dr. McCullough mentioned that the American Cancer Society has guidelines regarding cancer prevention. Those are here: http://www.cancer.org/healthy/eathealthygetactive/acsguidelinesonnutritionphysicalactivityforcancerprevention/

  • Hannah Jordan

    What about red wine-isn’t it supposed to be better white wine or beer?

  • The Forum Moderator

    We starting to run short on time. Apologies if we weren’t able to get to your question. As noted, we’ll ask our panelists if they can login to the page later and address some of these questions.

  • The Forum Moderator

    Just a reminder that we will post this full-length video on this site over this weekend, and, next week, we will post on YouTube and iTunes. The audio also will be posted.

  • The Forum Moderator

    We thank our media collaborator, The Huffington Post, as well as Harvard Health Publications.

  • The Forum Moderator

    We also thank ShareWIK (http://www.sharewik.com/) and Huffington Post for allowing us to use parts of videos that they produced.

  • Research

    Will a video of this forum be available for download or streaming after today?

    • The Forum Moderator

      Hi, It may be posted tonight — but, if not, it will be posted later this weekend.

    • The Forum Moderator

      Hi — just learned that it will be posted tomorrow, Saturday, January 16.

  • The Forum Moderator

    We also want to extend our sympathies to the family and friends of Dr. Lawrence Cohn, who passed away recently. This event is part of the Dr. Lawrence H. and Roberta Cohn Series.

  • The Forum Moderator

    Join us again on Tuesday, January 26, when The Forum will present “Preventing Gun Violence: Public Health Perspectives” in collaboration with Reuters. 12:30-1:30pm. ForumHSPH.org.

  • The Forum Moderator

    Thank you all for joining us today. Our event has concluded.

  • Kristen Lally

    QUESTIONS ANSWERED BY PANELISTS

    QUESTION: Is there data on the nitrates from the processed meat being more of the issue than the meat itself?

    ANSWER: There are a few different factors that may contribute to increasing the risk of colorectal (and possibly other) cancers from processed meat, including formation of N-nitroso compounds, like nitrosamines—either in the meat before consumption or in the gut after consumption, heme iron from red meats which facilitate the formation of nitrosamines in the body, and cooking meat at high temperatures and/or smoking meat which leads to formation of carcinogens. It is difficult to tease apart how much of a role each of these plays, but as Dr. Giovannucci mentioned, heme iron is thought to be quite important. So, if the meat itself is a red meat, the heme iron would also contribute to increased risk.

    QUESTION: Question for the panel: Is there a distinction between grass-fed red meat vs. conventional red meat?

    ANSWER: Data are not currently available from large epidemiological studies to determine whether grass fed vs conventional (red) meat is more strongly associated with cancer risk. If heme iron is one of the primary factors responsible for increased risk, then grass-fed meat would have a similar risk as conventional.

    QUESTION: I was unlucky enough to be sent off to school in the 60’s and 70’s with a bologna or liverwurst sandwich almost every day. Since my 20’s, I have reduced my processed meat consumption dramatically. Now I eat none. My question is, do we really know how much bearing early nutrition has on the overall picture of cancer risk and how much life style changes can truly “reverse” carcinogenic effects of poor choices of earlier years. What biometrics are used to measure lessening of risk after dietary changes?

    ANSWER: Changing dietary habits for the better is always a good idea, and the sooner the better. A few studies collected recalled high school diet, and some found a higher risk of colorectal adenoma (polyps) or breast cancer in people who reported eating a lot of red or processed meats during youth, but further research is needed to confirm these findings.

    What do you say about lunch meats with no nitrates or preservatives

    Fresh cooked poultry or fish are the best “meats” to eat to reduce exposure to compounds used in processing meat. Meat with “natural” ingredients and no nitrates or nitrites still may form nitrosamines in the gut; we do not know yet what their impact on cancer risk will be.

    QUESTION: Can the panel discuss the varying diets: standard American vs vegetarian vs vegan? Does one clearly offer improved health outcomes?

    ANSWER: Many different dietary patterns can be healthy by choosing well within that pattern. The “standard” American diet is generally not healthy, but can be made healthy with selection of quality proteins (poultry, fish, nuts, beans, and tofu), plant foods (plenty of vegetables and whole fruits, and whole grains) and oils. Alternative protein sources are available for those who follow a vegetarian diet.

    QUESTION: The NEJM came out earlier this year stating that glyphosate and GMO crops are “probable carcinogens”. Are there any changes in recommendations to these foods?

    ANSWER: There was a perspective from 2 authors on this topic. GM crops were not directly declared as probable carcinogens. Rather, the International Agency for Research on Cancer (IARC) has classified glyphosate, the herbicide most widely used on GM crops, as a “probable human carcinogen”. The authors recommend the reconsidering of all aspects of the safety of plant biotechnology. In fact, the National Academy of Sciences has convened a new committee that will reassess the social, economic, environmental, and human health effects of GM crops. The authors also recommend the possibility of labeling of GM foods, as is done in other countries. These developments bear scrutiny, but do not affect our current recommendations.

    QUESTION: What is the risk of eating turkey breast cold meat – no preservatives or salt added ? It is “processed”, but not a red meat and no nitrates

    ANSWER: IARC defines a processed meat as “meat that has been transformed through salting, curing, fermentation, smoking or other processes to enhance flavor or improve preservation”. If turkey breast was cooked from fresh meat, and not altered, then it would not be considered processed.

    QUESTION: Is it BMI or overall body composition (e.g. central fat deposits)?

    ANSWER: For some cancers, including colorectal cancer, central fat deposits (e.g. measured by waist circumference) have been a stronger predictor than overall body mass index (BMI) in some studies. Central body fat is more metabolically active and may lead to more insulin resistance and higher levels of circulating inflammatory factors in the body. However, for many cancers, BMI is the stronger determinant of risk. One should aim for both a healthy waist circumference and body mass index.

    QUESTION: What is the optimal BMI for minimizing exposure to Cancer?

    ANSWER: Being lean while also being healthy is optimal for cancer prevention. For example, a BMI range of 18.5 to 25.0 is considered “normal”, but risk of breast cancer is higher for women with a BMI in the higher range, compared to being in the lower end of the range. Some people who smoke or who have eating disorders have very low BMI which is not optimal.

    QUESTION: Can anyone talk about if diet or other therapies can help someone who has already been diagnosed with cancer (specifically small bowel cancer)?

    ANSWER: The American Cancer Society publishes guidelines for cancer survivors (put link). Unfortunately not too many studies have been conducted with small bowel cancer as this is relatively rare. However, small bowel cancer survivors with chronic bowel problems or surgery that affects normal nutrient absorption should be referred to a registered dietitian to modify their diets to accommodate these changes and maintain optimal health.

    QUESTION: Is a stronger microbiota able to reduce risk of cancer?

    ANSWER: There are more studies on the microbiota and obesity and diabetes, and little data on cancer. Hopefully this will be studied in the near future.

    QUESTION: How about whole foods plant-based diets? That would steer away BOTH from the red meats (as well as from other meats) AND from the sugars and other processed PLANTS (such as sugar) that we think are less health-supporting.

    ANSWER: This is consistent with the healthy diet patterns message we discussed – vegetarian diets can be quite healthy; however, you can also have a healthy diet if you also include other protein sources like fish, poultry and eggs.