Parnaud G, Corpet D E
Laboratoire sécurité des aliments, Institut national de la recherche agronomique, Ecole nationale vétérinaire, Toulouse, France.
Bull Cancer. 1997 Sep;84(9):899-911.
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.
饮食被认为会影响结直肠癌的病因，但确切的致病因素尚不清楚。国际生态学研究表明肉类消费与结直肠癌发病率之间存在很强的相关性。大多数病例对照研究（29项中的22项）表明，食用较多肉类的人患结直肠癌的风险增加。相比之下，5项最佳前瞻性队列研究中只有2项表明红肉存在这种正相关关系。4项研究中有2项表明与加工肉类有关联。食用白肉或鱼肉与高风险无关，甚至可能降低结直肠癌的发生率。关于肉类与结肠癌发生之间的联系，已经提出了几种合理的假设。这些假设涉及饱和脂肪、蛋白质、铁、烹饪产生的杂环胺以及N-亚硝基化合物。高脂肪饮食可能会促进癌症，因为它们热量高，或者因为它们会导致结肠腔内胆汁酸水平升高。关于肉类或肉类成分对用化学致癌物引发的啮齿动物结肠肿瘤发生率的影响，发表了6项实验研究。这些研究的数据并不支持红肉（牛肉）对肠道致癌作用有特定影响的观点。相反，与含有相似数量植物来源脂肪和蛋白质的对照饮食相比，含有牛肉（熟牛肉或生牛肉）的饮食会降低致癌作用。然而，与低脂肪或低蛋白质饮食相比，高脂肪或高蛋白质饮食通常会增加致癌作用。因此，既不能说肉类会促进结直肠癌，也不能排除这种可能性。
