Mechanisms linking colorectal cancer to the consumption of (processed) red meat : a review

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the world. The vast majority of CRC cases have been linked to environmental causes rather than to heritable genetic changes. Over the last decades, epidemiological evidence linking the consumption of red and, more convincingly, of processed red meat to CRC has accumulated. In parallel, hypotheses on carcinogenic mechanisms underlying an association between CRC and the intake of red and processed red meat have been proposed and investigated in biological studies. The hypotheses that have received most attention until now include (1) the presence of polycyclic aromatic hydrocarbons and heterocyclic aromatic amines, two groups of compounds recognized as carcinogenic, (2) the enhancing effect of (nitrosyl)heme on the formation of carcinogenic N-nitroso compounds and lipid peroxidation. However, none of these hypotheses completely explains the link between red and processed red meat intake and the CRC risk. Consequently, scientists have proposed additional mechanisms or refined their hypotheses. This review first briefly summarizes the development of CRC followed by an in-depth overview and critical discussion of the different potential carcinogenic mechanisms underlying the increased CRC risk associated with the consumption of red and processed red meat

Processed Meat and Colorectal Cancer: A Review of Epidemiologic and Experimental Evidence

Processed meat intake may be involved in the etiology of colorectal cancer, a major cause of death in affluent countries. The epidemiologic studies published to date conclude that the excess risk in the highest category of processed meat-eaters is comprised between 20 and 50% compared with non-eaters. In addition, the excess risk per gram of intake is clearly higher than that of fresh red meat. Several hypotheses, which are mainly based on studies carried out on red meat, may explain why processed meat intake is linked to cancer risk. Those that have been tested experimentally are (i) that high-fat diets could promote carcinogenesis via insulin resistance or fecal bile acids; (ii) that cooking meat at a high temperature forms carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons; (iii) that carcinogenic N-nitroso compounds are formed in meat and endogenously; (iv) that heme iron in red meat can promote carcinogenesis because it increases cell proliferation in the mucosa, through lipoperoxidation and/or cytotoxicity of fecal water. Nitrosation might increase the toxicity of heme in cured products. Solving this puzzle is a challenge that would permit to reduce cancer load by changing the processes rather than by banning processed meat

Untargeted metabolomics to reveal red versus white meat‐associated gut metabolites in a prudent and western dietary context

Scope: To improve understanding of the epidemiological link between red and processed meat consumption and chronic diseases, more insight in the formation of metabolites during meat digestion is warranted.Methods and results: Untargeted MS-based metabolomics was applied to explore the impact of red and processed meat consumption (compared to chicken), combined with a prudent or Western dietary pattern. A pig feeding study (n=32), as a sentinel for humans, was conducted in a 2×2 factorial design for four weeks. The luminal content of the small intestine and colon of the pigs were collected to determine their metabolic fingerprints. Seventy-six unique metabolites (38 in small intestine, 32 in colon, and 6 in both intestinal compartments) contributing tothe distinct gut metabolic profiles of pigs fed either chicken or red and processed meat were (tentatively) identified. Consumption of red and processed meat resulted in higher levels of short-and medium-chain acylcarnitines and 3-dehydroxycarnitine, irrespective of dietary context, whereas long-chain acylcarnitines and monoacylglycerols were specifically associated with the red and processed-Western diet.Conclusion: The identification of red and processed meat-associated gut metabolites in this study contributes to the understanding of meat digestion in a complex but controlled dietary context and its potential health effect

Consumer's stated trust in the food industry and meat purchases

Research indicates that consumers are particularly concerned about the safety of meat. More highly processed meat is perceived as more unsafe than fresh or natural meats, i.e., consumers trust processed meat less. This paper studies the relationship between perceived trust and day-to-day purchase behavior for meat, giving special attention to the degree of meat processing. Controlling for trust in food chain actors and demographic and socio-economic variables, actual meat purchases of Canadian households are linked to answers from a commissioned food attitudes survey completed by the same households. Expenditures for processed and total meat (but not for fresh meat) are significantly different by three levels of trust in the food industry. Consumer with the lowest trust levels consume less (especially of processed meat) compared to those with higher trust levels. However, in a multivariate setting, trust shows no effect on fresh or processed meat purchases with or without demographic and socio-economic control variables, suggesting that the impact of trust on meat purchases is only small. However, the low trusting consumer segment could potentially be a target for marketing strategies focused on reputation and quality to increase sales in this particular group.The final publication is available at Springer via: http://dx.doi.org/10.1007/s10460-012-9375-

Consumption of red or processed meat does not predict risk factors for coronary heart disease; results from a cohort of British adults in 1989 and 1999

Objectives—To investigate whether a high consumption of red or processed meat is associated with increased risk of coronary heart disease. Subjects/Methods—The subjects were 517 men and 635 women who were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort. Assessment of diet was carried out at two time-points 1989 and 1999 with outcome measures collected in 1999. Food intake data were recorded in 5 -day diaries. Meat consumption was estimated by adding individual meat portions to the meat fractions of composite dishes. Results—There was no significant association between red or processed meat consumption in 1989 and 1999 and serum cholesterol concentrations and blood pressure measured in 1999. The combined intake of red and processed meat in 1999 had a significant positive association with blood pressure in men only. Red and processed meat intakes in 1989 separately and combined had a significant positive association with waist circumference in 1999: a 10g increase in red meat consumption accounted for a 0.3cm increase in waist circumference; p=0.04 (men), 0.05 (women). Conclusions—Consumption of red or processed meat assessed separately was not related to the major risk factors for CHD but did contribute to increased waist circumference that has also been identified as a risk factor

Red and processed meat consumption and purchasing behaviours and attitudes: impacts for human health, animal welfare and environmental sustainability

Objective: Higher intakes of red and processed meat are associated with poorer health outcomes and negative environmental impacts. Drawing upon a population survey the present paper investigates meat consumption behaviours, exploring perceived impacts for human health, animal welfare and the environment. Design: Structured self-completion postal survey relating to red and processed meat, capturing data on attitudes, sustainable meat purchasing behaviour, red and processed meat intake, plus sociodemographic characteristics of respondents. Setting: Urban and rural districts of Nottinghamshire, East Midlands, UK, drawn from the electoral register. Subjects: UK adults (n 842) aged 18–91 years, 497 females and 345 males, representing a 35·6 % response rate from 2500 randomly selected residents. Results: Women were significantly more likely (P 60 years) were more likely to hold positive attitudes towards animal welfare (P<0·01). Less than a fifth (18·4 %) of the sample agreed that the impact of climate change could be reduced by consuming less meat, dairy products and eggs. Positive attitudes towards animal welfare were associated with consuming less meat and a greater frequency of ‘higher welfare’ meat purchases. Conclusions: Human health and animal welfare are more common motivations to avoid red and processed meat than environmental sustainability. Policy makers, nutritionists and health professionals need to increase the public’s awareness of the environmental impact of eating red and processed meat. A first step could be to ensure that dietary guidelines integrate the nutritional, animal welfare and environmental components of sustainable diets

Meat consumption after disaggregation of meat dishes in a cohort of British adults in 1989 and 1999 in relation to diet quality

Objectives—The aim of the study was to quantify more precisely the meat intake of a cohort of adults in the UK by disaggregating composite meat dishes. Subjects/Methods—Subjects were members of the MRC National Survey of Health and Development, 1946 birth cohort. Five-day diaries were collected from 2256 men and women in 1989 and 1772 men and women in 1999. From the details provided, composite meat dishes were broken down into their constituent parts and the meat fraction added to meat only portions. Meat intake was classified as red meat, processed meat and poultry. Results—Meat consumption without disaggregation of meat dishes resulted in a mean overestimation of 50% in men and 33% in women. Red meat consumption fell between 1989 and 1999 from 51.7 to 41.5g/day in men and 35.7 to 30.1g/day in women. Poultry consumption rose from 21.6 to 32.2g./day in men and 18.2 to 29.4 g/day in women. Re-calculating red meat intakes resulted in the percentage of subjects in 1999 consuming more the recommendation of the World Cancer Research Fund falling from 30% to 12 %. Increasing consumption of red and processed meat was associated with increased intakes of energy, fat, haem iron, zinc and vitamin B12 and lower intake of fibre. Increased sodium intake was associated with increased consumption of processed meat. Conclusions—Disaggregation of meat dishes provided a more precise estimate of meat consumption. The quantity of red or processed meat in the diet was reflected in the nutrient content of the entire diet

CONSUMER PREFERENCES AND EVALUATIONS OF A PROCESSED MEAT PRODUCT

Consumer/Household Economics,

Nutritional evaluation of lowering consumption of meat and meat products in the Nordic context

The World Cancer Research Fund (WCRF) recommended in 2007 that consumer intake of red meat is minimized and processed meat eliminated. The recommendation was based on a systematic review of the available literature on the association between meat consumption and cancer. The recommendation to individuals was to ingest less than 500 grams of red meat per weeks, and very little - if anything - processed meats. In a new study, National Food Institute has assessed the nutritional consequences from living the recommendations of the WCRF, in Norway, Sweden, Finland and Denmark. The current consumption of meat in the Nordic countries is not far from the level WCRF has proposed on an individual level. The study also shows that it will have no significant nutritional consequences to reduce the intake of meat to the recommended, neither when it comes to red meat nor processed meat