[Colorectal cancer: controversial role of meat consumption].
Diet is supposed to influence the colorectal cancer etiology, but the precise causative factors are yet unknown. International ecological studies show a strong correlation between meat consumption and the colorectal cancer incidence. Most case-control studies (22 of 29) show an increased risk to develop a colorectal cancer for those eating higher amounts of meat. In contrast, only 2 out of the 5 best prospective cohort studies have shown this positive association for red meat. Two studies out of 4 show an association with processed meat. Consumption of white meat or of fish is not associated with a high risk, and might even reduce the occurrence of colorectal cancer. Several plausible hypotheses concerning the link between meat and colon carcinogenesis have been suggested. They involve saturated fat, protein, iron, heterocyclic amines produced by cooking, and N-nitroso compounds. High fat diets may promote cancer because they have a high caloric content, or because they lead to increased levels of bile acids in the colonic lumen. Six experimental studies are published on the effect of meat, or meat fractions, on the colon tumor incidence in rodents initiated with chemical carcinogens. Data from these studies do not support the belief that red meat (beef) has a specific effect on intestinal carcinogenesis. Instead, diets containing beef meat (cooked or raw) decrease carcinogenesis when compared to control diets containing similar amounts of fat and protein of vegetal origin. However, high fat or high protein diets often increase carcinogenesis when compared to low fat or low protein diets. Thus, one cannot state, nor exclude, that meat promotes colorectal cancer.
Parnaud
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Laboratoire sécurité des aliments, Institut national de la recherche agronomique, Ecole nationale vétérinaire, Toulouse, France.
Corpet
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DE
D000588:Amines / Q000009:adverse effects; D000818:Animals; D002273:Carcinogens / Q000009:adverse effects / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D004041:Dietary Fats / Q000009:adverse effects; D004044:Dietary Proteins / Q000009:adverse effects; D005247:Feeding Behavior; D006801:Humans; D008460:Meat / Q000009:adverse effects*; D009603:Nitroso Compounds / Q000009:adverse effects; D009749:Nutrition Surveys; D051381:Rats; D012307:Risk Factors
D000588:Amines; D002273:Carcinogens; D004041:Dietary Fats; D004044:Dietary Proteins; D009603:Nitroso Compounds