The role of red and processed meat in colorectal cancer development: A perspective

Abstract Text: Red and processed meat provide high biological value proteins and important micronutrients, but at the same time there is increasing epidemiologic evidence for an association between red and processed meat consumption and the risk to develop several chronic diseases. With respect to colorectal cancer, meta-analyses have reported a 15-20% increased risk of colorectal cancer per 100 g per day of red meat and per 50 g per day of processed meat consumption. A working group of IARC recently assessed the carcinogenicity of red and processed meat consumption through an elaborate evaluation of epidemiologic, animal and mechanistic studies. Taking into account the amount of data, the nature and quality of the studies and the extent to which chance, bias and confounding from other dietary and lifestyle factors can be ruled out, it was concluded from the epidemiologic studies that there is sufficient evidence in human beings for the carcinogenicity of the consumption of processed meat, and limited evidence for red meat. Inadequate evidence was found in experimental animals, but the mechanistic evidence for carcinogenicity in the digestive tract was assessed as strong for red meat and moderate for processed meat. For genotoxicity and oxidative stress, evidence was considered moderate. Substantial supporting mechanistic evidence is available for multiple meat components (N-nitroso-compounds, haem iron, and heterocyclic aromatic amines). Taking this together, the IARC working group classified processed meat as ‘carcinogenic to humans’ and red meat as ‘probably carcinogenic to humans’. This classification has unfortunately frequently been misinterpreted and has led to polarized and scientifically incorrect statements in the media. However, it should be realized that the IARC assessment was a hazard analysis according to established procedures, and was not a full risk assessment, nor was it intended to make dietary recommendations. The question remains if nutrition authorities will adapt their advices on the role of meat in a healthy diet based on this report. This is evidently a concern for the meat industry. On the other hand, insight in the mechanisms of the association between meat consumption and diseases offers opportunities for mitigation, as was already shown for the use of calcium. More research is needed on the mechanisms and on strategies to improve the composition, processing and heating of meat, allowing to reduce the harmful effects. Even more important, it is believed that the interaction of meat with non-meat food ingredients in dietary patterns should be investigated.

Keywords: colorectal cancer, processed meat,red meat

See more of: Meat science and muscle biology symposium: Science of red meat consumption
See more of: Meat Science and Muscle Biology

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