van Poppel G, Verhoeven D T, Verhagen H, Goldbohm R A
TNO Nutrition and Food Research Institute, Zeist, The Netherlands.
Adv Exp Med Biol. 1999;472:159-68. doi: 10.1007/978-1-4757-3230-6_14.
This paper first gives an overview of the epidemiological data concerning the cancer-preventive effect of brassica vegetables, including cabbages, kale, broccoli, Brussels sprouts, and cauliflower. A protective effect of brassicas against cancer may be plausible due to their relatively high content of glucosinolates. Certain hydrolysis products of glucosinolates have shown anticarcinogenic properties. The results of six cohort studies and 74 case-control studies on the association between brassica consumption and cancer risk are summarized. The cohort studies showed inverse associations between the consumption of brassica's and risk of lung cancer, stomach cancer, all cancers taken together. Of the case-control studies 64% showed an inverse association between consumption of one or more brassica vegetables and risk of cancer at various sites. Although the measured effects might have been distorted by various types of bias, it is concluded that a high consumption of brassica vegetables is associated with a decreased risk of cancer. This association appears to be most consistent for lung, stomach, colon and rectal cancer, and least consistent for prostatic, endometrial and ovarian cancer. It is not yet possible to resolve whether associations are to be attributed to brassica vegetables per se or to vegetables in general. Further epidemiological research should separate the anticarcinogenic effect of brassica vegetables from the effect of vegetables in general. The mechanisms by which brassica vegetables might decrease the risk of cancer are reviewed in the second part of this paper. Brassicas, including all types of cabbages, broccoli, cauliflower, and Brussels sprouts, may be protective against cancer due to their glucosinolate content. Glucosinolates are usually broken down through hydrolysis catalysed by myrosinase, an enzyme that is released from damaged plant cells. Some of the hydrolysis products, viz. indoles, and isothiocyanates, are able to influence phase 1 and phase 2 biotransformation enzyme activities, thereby possibly influencing several processes related to chemical carcinogenesis, e.g. the metabolism, DNA-binding, and mutagenic activity of promutagens. Most evidence concerning anticarcinogenic effects of glucosinolate hydrolysis products and brassica vegetables has come from studies in animals. In addition, studies carried out in humans using high but still realistic human consumption levels of indoles and brassica vegetables have shown putative positive effects on health. The combination of epidemiological and experimental data provide suggestive evidence for a cancer preventive effect of a high intake of brassica vegetables.
本文首先概述了有关十字花科蔬菜防癌作用的流行病学数据，这些蔬菜包括卷心菜、羽衣甘蓝、西兰花、抱子甘蓝和花椰菜。十字花科蔬菜对癌症具有保护作用似乎是合理的，因为它们的硫代葡萄糖苷含量相对较高。硫代葡萄糖苷的某些水解产物已显示出抗癌特性。总结了六项队列研究和74项病例对照研究关于食用十字花科蔬菜与癌症风险之间关联的结果。队列研究表明，食用十字花科蔬菜与肺癌、胃癌以及所有癌症综合风险之间呈负相关。在病例对照研究中，64%显示食用一种或多种十字花科蔬菜与不同部位癌症风险之间呈负相关。尽管所测效应可能因各种类型的偏倚而失真，但得出的结论是，大量食用十字花科蔬菜与降低癌症风险相关。这种关联在肺癌、胃癌、结肠癌和直肠癌方面似乎最为一致，而在前列腺癌、子宫内膜癌和卵巢癌方面最不一致。目前尚无法确定这种关联是归因于十字花科蔬菜本身还是一般蔬菜。进一步的流行病学研究应将十字花科蔬菜的抗癌作用与一般蔬菜的作用区分开来。本文第二部分回顾了十字花科蔬菜可能降低癌症风险的机制。十字花科蔬菜，包括所有类型的卷心菜、西兰花、花椰菜和抱子甘蓝，由于其硫代葡萄糖苷含量，可能对癌症具有保护作用。硫代葡萄糖苷通常通过由黑芥子酶催化的水解作用分解，黑芥子酶是一种从受损植物细胞中释放出来的酶。一些水解产物，即吲哚和异硫氰酸盐，能够影响I相和II相生物转化酶的活性，从而可能影响与化学致癌作用相关的几个过程，例如前诱变剂的代谢、DNA结合和诱变活性。关于硫代葡萄糖苷水解产物和十字花科蔬菜抗癌作用的大多数证据来自动物研究。此外，在人类中使用高但仍符合实际的吲哚和十字花科蔬菜食用水平进行的研究表明对健康有假定的积极影响。流行病学和实验数据的结合为大量摄入十字花科蔬菜的防癌作用提供了提示性证据。
