Ziegler R G
Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892.
J Nutr. 1989 Jan;119(1):116-22. doi: 10.1093/jn/119.1.116.
The epidemiologic evidence that carotenoids are involved in cancer etiology is evaluated. Low intake of vegetables and fruits and carotenoids is consistently associated with an increased risk of lung cancer in both prospective and retrospective studies. In addition, low levels of serum or plasma beta-carotene are consistently associated with the subsequent development of lung cancer. The simplest explanation is that beta-carotene is indeed protective. Since retinol is not related in a similar manner to lung cancer risk, beta-carotene seems to play a role that does not require its conversion into vitamin A. However, the importance of other carotenoids, other constituents of vegetables and fruits, and other nutrients whose levels in the blood are partially correlated with those of beta-carotene has not been adequately explored. In addition, smoking, a powerful risk factor for lung cancer, is associated with reduced intake of carotenoids and lowered blood levels of beta-carotene and has not always been adequately controlled in these analyses. Prospective and retrospective studies suggest that carotenoids may reduce the risk of certain other cancers; however, too few studies have looked at these sites to examine the consistency of the evidence. Although clinical trials of the efficacy of beta-carotene in cancer prevention are underway, it is still necessary and prudent to continue well-designed prospective and retrospective studies of the carotenoid hypothesis.
本文评估了类胡萝卜素与癌症病因相关的流行病学证据。在前瞻性和回顾性研究中，蔬菜、水果和类胡萝卜素的低摄入量始终与肺癌风险增加相关。此外，血清或血浆中β-胡萝卜素水平较低也始终与随后肺癌的发生相关。最简单的解释是β-胡萝卜素确实具有保护作用。由于视黄醇与肺癌风险不存在类似的关联方式，β-胡萝卜素似乎发挥着一种不需要转化为维生素A的作用。然而，其他类胡萝卜素、蔬菜和水果中的其他成分以及血液中水平与β-胡萝卜素部分相关的其他营养素的重要性尚未得到充分探究。此外，吸烟作为肺癌的一个强大风险因素，与类胡萝卜素摄入量减少以及血液中β-胡萝卜素水平降低相关，并且在这些分析中吸烟情况并不总是得到充分控制。前瞻性和回顾性研究表明，类胡萝卜素可能会降低某些其他癌症的风险；然而，针对这些部位进行研究以检验证据一致性的研究过少。尽管β-胡萝卜素预防癌症功效的临床试验正在进行，但继续开展精心设计的类胡萝卜素假说前瞻性和回顾性研究仍然是必要且审慎的。
