Meat, Meat cooking methods and preservation, and risk for colorectal carcinoma

Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Cancer Research (Impact Factor: 9.33). 10/2005; 65(17):8034-41. DOI: 10.1158/0008-5472.CAN-04-3429
Source: PubMed


Cooking meat at high temperatures produces heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Processed meats contain N-nitroso compounds. Meat intake may increase cancer risk as HCAs, PAHs, and N-nitroso compounds are carcinogenic in animal models. We investigated meat, processed meat, HCAs, and the PAH benzo(a)pyrene and the risk of colorectal adenoma in 3,696 left-sided (descending and sigmoid colon and rectum) adenoma cases and 34,817 endoscopy-negative controls. Dietary intake was assessed using a 137-item food frequency questionnaire, with additional questions on meats and meat cooking practices. The questionnaire was linked to a previously developed database to determine exposure to HCAs and PAHs. Intake of red meat, with known doneness/cooking methods, was associated with an increased risk of adenoma in the descending and sigmoid colon [odds ratio (OR), 1.26; 95% confidence interval (95% CI), 1.05-1.50 comparing extreme quintiles of intake] but not rectal adenoma. Well-done red meat was associated with increased risk of colorectal adenoma (OR, 1.21; 95% CI, 1.06-1.37). Increased risks for adenoma of the descending colon and sigmoid colon were observed for the two HCAs: 2-amino-3,8-dimethylimidazo[4,5]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5]pyridine (OR, 1.18; 95% CI, 1.01-1.38 and OR, 1.17, 95% CI, 1.01-1.35, respectively) as well as benzo(a)pyrene (OR, 1.18; 95% CI, 1.02-1.35). Greater intake of bacon and sausage was associated with increased colorectal adenoma risk (OR, 1.14; 95% CI, 1.00-1.30); however, total intake of processed meat was not (OR, 1.04; 95% CI, 0.90-1.19). Our study of screening-detected colorectal adenomas shows that red meat and meat cooked at high temperatures are associated with an increased risk of colorectal adenoma.

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    • "family , including CYP1A1 and 1B1 , can activate dietary pro - carcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons , which have been associated with colorectal cancer ( Ito et al , 1991 ; Crofts et al , 1997 ; Barrett et al , 2003 ; Boyce et al , 2004 ; Sinha et al , 2005 ; Nothlings et al , 2009 ) , and the expression of CYP450 enzymes in tissues that are targets for xenobiotic genotoxicity implies a potential for in situ activation . CYP450s , in particular CYP2E1 , can also metabolise several drugs resulting in either inhibition or activation , and thus have an important role in drug bioavailability ( Koop , 1992 ) . "
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    • "The human activity, including fossil fuel combustion and industrial processing, is the primary source of PAHs contamination in the environment, but they can be also generated by natural phenomena, such as forest fires. Recent studies have shown that high level of PAHs are found in meat cooked at high temperatures (Sinha et al., 2005) and in smoked fish (Stolyhwo and Sikorski, 2005). These ubiquitous environmental contaminants have raised considerable misgivings, because many PAHs, besides the negative impacts on the surrounding ecosystem, have been shown to have potential mutagenic, carcinogenic and teratogenic activities after being metabolized (Bofetta et al., 1997; Ismert et al., 2002), causing adverse health effects; their hydrophilic character allows them to enter cells easily, inducing the metabolic system that will transform these molecules (Ismert et al., 2002). "
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    • "Polycyclic aromatic hydrocarbons (PAHs) have long been recognized as one group of global pollutants found in complex mixtures that mainly originate from incomplete combustion related to numerous anthropogenic sources such as petroleum fuels, refining industries, and production processes (Boonyatumanond et al. 2006, Hylland 2006, Marie et al. 2009, Nelson 2009, Shen et al. 2011b, Simoneit et al. 2005, Timoney and Lee 2011, Yang et al. 1998). Moreover, PAHs are also found in various heating fumes and cigarette smoke etc. (Castro et al. 2011, Ohura et al. 2003, Phillips 1999, Sinha et al. 2005, Wretling et al. 2010). PAHs belong to a class of several hundred individual chemicals that contains at least two fused benzenoid rings. "
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