Perhaps you have heard that eating meat – particularly red meat and processed meat — can cause cancer. But what meats are the most dangerous, how severe are the risks, and what steps can we take to minimize these risks?
To be clear, ‘red meat’ here refers to beef, pork, lamb, and goat from domesticated animals and ‘processed meat’ refers to meat preserved by smoking, curing or salting, or the addition of chemical preservatives.
Meats like sausages and bacon are processed with nitrates and nitrites to enhance flavor and color, and retard spoilage. According to the Food and Drug Administration (FDA), “Nitrites and, less often, nitrates are used as preservatives in foods such as cured meats, for example, bacon and salami.” The FDA goes on to say that “Exposure to higher levels of nitrates or nitrites has been associated with increased incidence of cancer in adults, and possible increased incidence of brain tumors, leukemia, and nasopharyngeal (nose and throat) tumors in children in some studies but not others.” The FDA also mentions that “The World Health Organization International Agency for Research on Cancer (IARC) ranked nitrates and nitrites high on the priority list for upcoming review of possible carcinogenicity.”1
Recently, researchers found that cooking both processed meats and non-processed red meats at high temperatures causes other carcinogenic chemicals to form. The chemicals in question are HCAs (heterocyclic amines) and PAHs (polycyclic aromatic hydrocarbons). Studies show that the higher the cooking temperature, the higher the amount of HCAs and PAHs that are produced. And the more of these well-cooked meats that are consumed, the higher the risk is for getting cancer. The risk is particularly great for colorectal cancer (cancer of the colon and/or rectum). In developed countries—particularly Australia and New Zealand, Europe, and North America–colorectal cancers are the third leading cause of death among men and the second in women.2
In one U.S. study, 39,000 men and women from ten different U.S. states had their diets assessed using a 137-item food questionnaire.3 In addition, the participants all agreed to submit to a sigmoidoscopy, an exam used to evaluate the lower part of the large intestine (colon). The group was questioned on how often they ate red meat, how much of it they ate, and how they cooked it. They were asked specifically about doneness level: Were their steaks and hamburgers cooked rare, medium-rare, medium, medium-well, well-done, or very well-done? Were their pork chops, ham steaks, sausage, hotdogs, and bacon cooked just until done, well-done/crisp, or very well-done/charred? Were their cooking methods bake/roast, pan-fry, grill/barbecue, microwave, or oven-broil? An increased risk of colorectal adenoma (non-cancerous tumor) was shown to be associated with eating well-done red meat, bacon, and sausage. The higher the intake of well-done red meat, bacon and sausage, the higher the risk of adenoma of the colon.
In 2013, it was further pointed out that high intakes of very specific types of red meat were associated with a higher risk of specific types of cancer. In a study of 54,000 Danish participants, the risk for colon cancer was found to be significantly elevated for higher intake of lamb whereas the risk for rectal cancer was elevated for higher intake of pork.4
This year, another, smaller study was conducted with patients already diagnosed with colorectal cancer. Their diets were compared with those of unaffected siblings and spouses.5 In this study, diets high in pan-fried beefsteaks and in oven-broiled short ribs or spareribs revealed an increased risk for colorectal cancer.
What is evident from these studies is that high consumption of red meat and processed red meat cooked at high temperatures poses some level of risk for both cancer and for pre-cancerous symptoms of the lower intestines. What is lacking are precise dietary and cooking guidelines to help curb these risks.
What you can do
The experts continue to study our diets, because they have not yet reached an agreement about exactly how much processed or red meat is safe to eat, or for exactly how long it should be cooked for healthiest consumption. But based on what is known so far, there are several conservative cooking and dietary recommendations that may help to minimize your risk of cancer:
- The American Cancer Society informs us that “HCA and PAH formation can be reduced by avoiding direct exposure of meat to an open flame or a hot metal surface, and reducing the cooking time.”6
- The Centers for Disease Control (CDC) recommends that you reduce the amount of cured and processed meats in your diet, including bacon, bologna, corned beef, hot dogs, luncheon meats, sausages and canned and cured meat, and hams.7
- The World Cancer Research Fund and the American Institute for Cancer Research jointly recommend that people who eat red meat should consume less than 18 ounces a week, and very little if any of this should be processed.8
- A growing number of health professionals recommend that you consider a vegetarian diet. There is already evidence to support the fact that vegetarians have a significantly reduced cancer risk compared with meat-eaters.9
As meat consumption increases throughout the world, and the number of people diagnosed with cancer also increases, hopefully, researchers will continue to devote more time and resources to help people align dietary choices with overall good health.
Editor’s Note: This well-written article provides a good case for reducing our intake of heavily cooked and processed red meat. I would add a few observations:
- Not everyone can thrive as a vegetarian, especially since some meat-free diets are really “starchetarian” diets.
- Even if we do not totally remove red meat from our diet, we can reduce our portion size to one-third of what we used to consume and can replace some of our meat choices with plant-based proteins like beans, nuts, seeds, and legumes.
- If we accompany a meat dish with large portions of vegetables, that will help minimize the negative effects of the meat.
- Fruits like kiwi and pineapple can neutralize carcinogenic nitrosamines, formed when nitrites combine with amino acids in the stomach.
There are over 35 particular foods, including apples, beets, cabbage, garlic, leeks, oregano, turnips, and watercress, that fight colon cancer via dozens of different mechanisms. To learn more about specific foods that turn off colon and other cancers, you may wish to read BeatCancer.org’s new publication, Alphabetical Beat Cancer Diet Guide
 U.S. Food and Drug Administration. EPA, Toxicity and Exposure Assessment for Children’s Health Nitrates and Nitrites – Teach, Chemical Summary. U.S. EPA, Toxicity and Exposure Assessment for Children’s. Last revised 5/22/07: includes research articles and other information through 2006. http://www.epa.gov/teach/chem_summ/Nitrates_summary.pdf
 Jemal, A., Bray, F., Center, M.M., et al. Global Cancer Statistics. CA: A Cancer Journal for Clinicians. March/April 2011. Volume 61 Volume 61, Issue 2; :69–90. http://onlinelibrary.wiley.com/doi/10.3322/caac.20107/full
 Sinha, R., Peters, U., Cross, A.J., et al. Meat, Meat Cooking Methods and Preservation, and Risk for Colorectal Adenoma. Cancer Research 2005; 65:8034. http://cancerres.aacrjournals.org/content/65/17/8034.long
 Egeberg R., Olsen A., Christensen J., et al. Associations between red meat and risks for colon and rectal cancer depend on the type of red meat consumed. Journal of Nutrition 2013; 143(4):464-72. doi: 10.3945/jn.112.168799. Epub 2013 Feb 20. http://jn.nutrition.org/content/143/4/464.long
 Joshi AD, Kim A, Lewinger JP, et al. Meat intake, cooking methods, dietary carcinogens, and colorectal cancer risk: findings from the Colorectal Cancer Family Registry. Cancer Med. 2015 Apr 7. doi: 10.1002/cam4.461. [Epub ahead of print]
 American Cancer Society. 2010. Chemicals in Meat Cooked at High Temperatures and Cancer Risk. http://www.cancer.gov/cancertopics/causes-prevention/risk/diet/cooked-meats-fact-sheet
 Agency for Toxic Substances and Diseases Registry (ATSDR). Nitrate/Nitrite Toxicity. What Instructions Should Be Given to Patients to Prevent Overexposure to Nitrates and Nitrites? http://www.atsdr.cdc.gov/csem/csem.asp?csem=28&po=14
 The World Cancer Research Fund and the American Institute for Cancer Research. Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective. 2007. http://www.aicr.org/assets/docs/pdf/reports/Second_Expert_Report.pdf
 Phillips R.L. Role of lifestyle and dietary habits in risk of cancer among Seventh-day Adventists. Cancer Res 1975; 35(suppl):3513-3522.