RESULTS: The 2017 WCRF/AICR Continuous Update Project on colorectal cancer concluded that there is convincing evidence linking several individual dietary factors with CRC risk but the evidence for dietary patterns was limited and inconclusive. Also, previous reviews and meta-analyses have not critically synthesized various dietary patterns. This review synthesized data from dietary patterns studies over a 17-year period from 2000 to 2016.
CONCLUSIONS: We included 49 studies (28 cohort and 21 case-control) that examined the association of index-based and empirically-derived dietary patterns and CRC risk. A synthesis of food group components comprising the different index-based and empirically-derived patterns revealed two distinct dietary patterns associated with CRC risk. A \"healthy\" pattern, generally characterized by high intake of fruits and vegetables, wholegrains, nuts and legumes, fish and other seafood, milk and other dairy products, was associated with lower CRC risk. In contrast, the \"unhealthy\" pattern, characterized by high intakes of red meat, processed meat, sugar-sweetened beverages, refined grains, desserts and potatoes was associated with higher CRC risk. It is notable that the number of food groups, the intake quantity, the exact types of foods in each food group, differed between populations, yet the two dietary patterns remained consistent across regions, especially in empirically-derived patterns, an indication of the high reproducibility of these patterns. However, findings for CRC risk in both index-based and empirically-derived patterns, differed by sex, with stronger associations among men than women; study design, a higher proportion of case-control studies reported significant findings compared to prospective studies. Consuming a dietary pattern high in fruits and vegetables and low in meats and sweets is protective against CRC risk. However, important questions remain about mechanisms underlying differences by sex; life-course timing of exposure to dietary patterns; interaction of dietary patterns with the microbiome or with lifestyle factors including physical activity; and elucidation of subsite differences.
结果:2017年WCRF/AICR结直肠癌持续更新项目得出结论,有令人信服的证据将几个个体饮食因素与CRC风险联系起来,但饮食模式的证据有限且尚无定论。此外,以前的综述和荟萃分析没有严格地综合各种膳食模式.这篇综述综合了2000年至2016年17年间饮食模式研究的数据。
结论:我们纳入了49项研究(28项队列研究和21项病例对照研究),研究了基于指数和经验得出的饮食模式与CRC风险之间的关系。包含不同的基于指数和经验得出的模式的食物组成分的合成揭示了与CRC风险相关的两种不同的饮食模式。一个“健康”的模式,一般特点是水果和蔬菜摄入量高,全麦,坚果和豆类,鱼和其他海鲜,牛奶和其他乳制品,与较低的CRC风险相关。相比之下,“不健康”模式,其特点是红肉摄入量高,加工肉,含糖饮料,精制谷物,甜点和土豆与更高的CRC风险相关。值得注意的是,食物组的数量,摄入量,每个食物组中食物的确切类型,不同种群之间的差异,然而,这两种饮食模式在不同地区保持一致,特别是在经验推导的模式中,表明这些模式的高再现性。然而,基于指数和经验推导模式的CRC风险发现,不同的性别,男性比女性有更强的联系;研究设计,与前瞻性研究相比,更高比例的病例对照研究报告了显著的结果.食用水果和蔬菜含量高,肉类和甜食含量低的饮食模式可以预防CRC风险。然而,重要的问题仍然存在于以下方面:性别差异的潜在机制;暴露于饮食模式的生命周期时间;饮食模式与微生物组或包括身体活动在内的生活方式因素的相互作用;以及亚位点差异的阐明。