The World Health Organization (WHO) made headlines when it declared processed meat a "carcinogen" and unprocessed red meat as “probably carcinogenic [1]” .
Red meat refers to unprocessed mammalian muscle meat— beef, veal, pork, lamb. Processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.
Meat processing can result in formation of known carcinogenic chemicals, including N-nitroso-compounds (NOC) and polycyclic aromatic hydrocarbons (PAH) and heme iron.
Cooking improves the digestibility and palatability of meat, but can also produce known or suspected carcinogens, including heterocyclic aromatic amines (HAA) and PAH. High-temperature cooking by panfrying, grilling, or barbecuing generally produces the highest amounts of these chemicals [2] .
In three intervention studies in human beings, changes in oxidative stress markers (either in urine, feces, or blood) were associated with consumption of red meat or processed meat [3]. Oxidative stress can damage cells, proteins, and DNA, which can contribute to aging. It may also play a role in development of a range of health conditions, including diabetes, cancer, and neurodegenerative diseases such as Alzheimer’s [4] . Anti-oxidants abound in plants.
WHO’s International Agency for Research on Cancer classified consumption of red meat as “probably carcinogenic to humans”. In making this evaluation, they took into consideration all relevant data, including the substantial epidemiological data showing a positive association between consumption of red meat and colorectal cancer and the strong mechanistic evidence. Consumption of red meat was also positively associated with pancreatic and with prostate cancer.
Not just cancer
The more red meat you eat, the greater your risk of dying from one of eight diseases, according to a recent report [5] . High red meat consumption increased the rate of dying from cancer, heart disease, respiratory disease, stroke, diabetes, infections, kidney disease and liver disease.
The U.S. Department of Agriculture (USDA) reports that 70 percent of food poisoning is caused by contaminated animal flesh. Foodborne diseases, such as E. Coli, Salmonella, and Campylobacter, cause an estimated 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year [6] .
References
[1] International Agency for Research on Cancer. Volume 114: Consumption of red meat and processed meat. IARC Working Group. Lyon; 6–13 September, 2015. IARC Monogr Eval Carcinog Risks Hum
[2] Alomirah H, Al-Zenki S, Al-Hooti S, et al. Concentrations and dietary exposure to polycyclic aromatic hydrocarbons (PAHs) from grilled and smoked foods. Food Control 2011; 22: 2028–35.
[3] Pierre FH, Martin OC, Santarelli RL, et al. Calcium and alpha-tocopherol suppress cured-meat promotion of chemically induced colon carcinogenesis in rats and reduce associated biomarkers in human volunteers. Am J Clin Nutr 2013; 98: 1255–62
[4] Liguori I, Russo G, Curcio F, et al. Oxidative stress, aging, and diseases. Clin Interv Aging. 2018;13:757-772. Published 2018 Apr 26. doi:10.2147/CIA.S158513
[5] Etemadi A, Sinha R, Ward M H, Graubard B I, Inoue-Choi M, Dawsey S M et al. Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: population based cohort study BMJ 2017; 357 :j1957 doi:10.1136/bmj.j1957
[6] Shew, Abigail, Are You Sure It Wasn’t Food Poisoning? Food Safety Education Staff, Food Safety and Inspection Service, USDA in Health and Safety, May 07, 2019