摘要
Evidence from both epidemiological and experimental observations have fueled the belief that the high consumption of fruits and vegetables rich in carotenoids may help prevent cancer and heart disease in humans. Because of its well-documented antioxidant and antigenotoxic properties, the carotenoid β-carotene (βCT) gained most of the attention in the early 1980s and became one of the most extensively studied cancer chemopreventive agents in population-based trials supported by the National Cancer Institute. However, the results of three randomized lung cancer chemoprevention trials on βCT supplementation unexpectedly contradicted the large body of epidemiological evidence relating to the potential benefits of dietary carotenoids. Not only did βCT show no benefit, it was associated with significant increases in lung cancer incidence, cardiovascular diseases, and total mortality. These findings aroused widespread scientific debate that is still ongoing. It also raised the suspicion that βCT may even possess co-carcinogenic properties. In this review, we summarize the current data on the co-carcinogenic properties of βCT that is attributed to its role in the induction of carcinogen metabolizing enzymes and the over-generation of oxidative stress. The data presented provide convincing evidence of the harmful properties of this compound if given alone to smokers, or to individuals exposed to environmental carcinogens, as a micronutrient supplement. This has now been directly verified in a medium-term cancer transformation bioassay. In the context of public health policies, while the benefits of a diet rich in a variety of fruits and vegetables should continue to be emphasized, the data presented here point to the need for consideration of the possible detrimental effects of certain isolated dietary supplements, before mass cancer chemoprevention clinical trials are conducted on human subjects. This is especially important for genetically predisposed individuals who are environmentally or occupationally exposed to mutagens and carcinogens, such as those found in tobacco smoke and in industrial settings.
摘要译文
从流行病学和实验观察结果都引发了一个信念：富含类胡萝卜素的高水果蔬菜可能有助于预防人类癌症和心脏病。由于其良好的抗氧化和抗原毒性，（βCT）在二十世纪八十年代早期获得了最多的关注，并成为美国国家癌症研究所（National Cancer Institute）支持的基于人群的试验中最广泛研究的癌症化学预防剂之一。然而，3个随机化的肺癌化学预防试验对βCT补充剂出乎意料地与大量有关膳食类胡萝卜素潜在益处的流行病学证据相矛盾。βCT不仅没有获益，而且与肺癌发病率，心血管疾病和总死亡率显着增加有关。这些调查结果引起了广泛的科学讨论，但仍在进行中。这也提出了βCT甚至可能具有共同致癌性质的怀疑。在这篇评论中，我们总结了目前关于βCT的致癌性质的数据，归因于其在致癌物代谢酶的诱导和氧化应激的过度产生中的作用。所提供的数据提供了令人信服的证据，证明如果单独给吸烟者或暴露于环境致癌物的个体，该化合物的有害性质，作为微量营养素补充剂。现在已经在中期癌症转化生物测定中直接证实了这一点。在公共卫生政策方面，而应继续强调富含各种水果和蔬菜的饮食的好处，这里提供的数据表明需要考虑某些孤立膳食补充剂的可能有害作用，在对人体进行大规模癌症化学预防临床试验之前。这对环境或职业暴露于诱变剂和致癌物质的遗传易感个体尤其重要，如在烟草烟雾和工业环境中发现的那些。
MorenoPaolini[a];Sherif ZAbdel-Rahman[b];AndreaSapone[a];Gian FrancoPedulli[c];PaoloPerocco[d];GiorgioCantelli-Forti[a][b];Marvin SLegator[b];. β-Carotene: a cancer chemopreventive agent or a co-carcinogen?[J]. Mutation Research/Reviews in Mutation Research, 2003,543(3): 195-200