Author: Macquin Anduwan
Each day, millions of people around the world consume processed meat in one form or another. Sausages, bacon, salami, tinned meat, or fish, all of which are eaten regularly by the typical urban household. Yet, despite the fact that these processed meat have been classified by the World Health Organization as a Group 1 level carcinogen, many people continue to consume this carcinogen without a second thought. Even more so given that there have been numerous articles to date showing that the consumption of processed meat is carcinogenic.
A carcinogen is defined as any substance that may cause cancer . These may be anything from chemicals in cosmetics, foods, drinks, or commercial wastes, and may be found even in polluted air or through radiation exposure .
Red meat is usually used to make processed meat. It is typically cured, smoked, or salted which improves the durability of the food, the colour, and taste, and it often contains a high amount of minced fatty tissues. Thus, high consumption of processed foods would lead to a higher intake of saturated fats, salts, haem iron, nitrite, polycyclic aromatic hydrocarbons, and also heterocyclic amines depending on the preparation method .
In the case of processed meat, and even red meat, several studies have shown that certain chemicals are responsible for bringing about these carcinogenic changes . These chemicals can be both naturally occurring and added. When red meat is broken down in the body, one of such chemicals – haem –forms N-nitroso chemicals, which have been seen to be disruptive toward the cells lining the colorectal region . This increases the risks of colorectal cancer. Processed meat, just like red meat, also forms N-nitroso chemicals, however, in addition to such, the nitrite and nitrate preservatives that are commonly used as processed meat preservatives also produce N-nitroso chemicals, increasing the risks of colorectal cancer .
The cooking of meat can also produce other carcinogens such as heterocyclic aromatic amines and polycyclic aromatic hydrocarbons . Pan-frying, grilling, barbequing, and high-temperature cooking have been shown to generate higher amounts of said carcinogens .
A study conducted a few years ago on the relationship between processed meat and colorectal cancer took to review epidemiological and experimental evidence. In this article, epidemiological data concluded that compared with non-eaters of processed meat, those in the category of high processed meat-eaters had an excess risk of colorectal cancer comprised between 20 and 50% . Additionally, the excess risk per gram was noticeably higher when compared to red meat intake.
Experimental studies on red meat and processed meat were typically based on three hypotheses: (i) diets rich in fats could promote carcinogenesis via insulin resistance or faecal bile acids; (ii) cooking meat at high temperatures forms heterocyclic amines and polycyclic aromatic hydrocarbons, both carcinogenic chemicals; (iii) meat had carcinogenic N-nitroso compounds found endogenously; and (iv) carcinogenesis can be caused by haem iron in red meat, which increases cell proliferation in the mucosa through lipoperoxidation and/or the cytotoxicity of faecal water .
In 2007, another study on the relation of red and processed meat in relation to cancer risk was conducted. In it, an eight-year follow-up ascertained an increased risk for individuals in the highest quintile of the processed meat-eaters showing a 20% elevated risk for colorectal cancer and a 16% elevated risk for lung cancer .
A few years later, an international advisory committee met in 2014 to recommend that the International Agency for Research on Cancer (IARC) Monographs Programme evaluate red and processed meat as high priorities . This eventuated in processed meats being classed as Group 1 carcinogens and red meats as Group 2A, which are listed as probable to cause cancer.
According to the World Health Organization on estimates given out by the Global Burden on Disease Project, about 34 000 cancer deaths each year are attributed to diets high in processed meat .
Eating 50 grams of processed meat a day (the equivalent of 1 sausage or 4 bacon strips) was stated to increase the risk of colorectal cancer by 18%, according to the American Cancer Society . Red meat, on the other hand, showed evidence of increased colorectal, pancreatic, and prostate cancer .
At present, there are several studies showing the relation between processed meat as a very influential aetiology of colorectal cancer, as well as increased risks of other types of cancer. Until new methods of food processing can avoid or prevent the carcinogenic properties in processed meat and red meat, a diet with little or no red meat and processed meat would be more recommended. Even better yet, if red meat and processed meat are avoided altogether. Nutritional benefits could be obtained through poultry, eggs, or even a plant-based diet while making, sure enough, iron, vitamin B12, and other essential nutrients are received.
"Common Carcinogens You Should Know," WebMD, [Online]. Available: https://www.webmd.com/cancer/know-common-carcinogens#1. [Accessed 8 October 2020].
S. Rohrmann and J. Linseisen, "Processed meat: the real villain?," The Proceedings the the Nutrition Society, vol. 75, no. 3, pp. 233-241, 2016.
"Red meat, processed meat and cancer," Cancer Council of Australia, [Online]. Available: https://www.cancercouncil.com.au/1in3cancers/lifestyle-choices-and-cancer/red-meat-processed-meat-and-cancer/. [Accessed 9 October 2020].
"Red Meat and Processed Meat," National Center for Biotechnology Information, 2018. [Online]. Available: https://www.ncbi.nlm.nih.gov/books/NBK507971/. [Accessed 11 October 2020].
R. L. Santarelli, F. Pierre and D. E. Corpet, "Processed meat and colorectal cancer: a review of epidemiologic and experimental evidence," National Center for Biotechnology Information, 27 March 2009. [Online]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2661797/#:~:text=Processed%20meat%20intake%20may%20be,%25%20compared%20with%20non%2Deaters.. [Accessed 11 October 2020].
A. J. Cross, M. F. Leitzmann, M. H. Gail, A. R. Hollenbeck, A. Schatzkin and R. Sinha, "A prospective study of red and processed meat intake in relation to cancer risk," PLos Medicine, vol. 4, no. 12, p. 325, 2007.
"Q&A on the carcinogenicity of the consumption of red meat and processed meat," World Health Organization, 26 October 2015. [Online]. Available: https://www.who.int/westernpacific/news/q-a-detail/q-a-on-the-carcinogenicity-of-the-consumption-of-red-meat-and-processed-meat. [Accessed 11 October 2020].
"World Health Organization Says Processed Meat Causes Cancer," American Cancer Society, 26 October 2015. [Online]. Available: https://www.cancer.org/latest-news/world-health-organization-says-processed-meat-causes-cancer.html. [Accessed 11 October 2020].
A. Valavanidis, "Consumption of REd and Processed Meat and Elevated Risk of Cancer to Humans," Research Gate, January 2016. [Online]. Available: https://www.researchgate.net/publication/290989654_Consumption_of_Red_and_Processed_Meat_and_Elevated_Risk_of_Cancer_to_Humans_Formation_of_Carcinogenic_Substances_Mechanisms_of_Carcinogenesis_and_Risk_Assessment_for_Colorectal_and_Other_Types_of_Canc. [Accessed 8 October 2020].