Block G
Division of Cancer Prevention and Control, National Cancer Institute, Bethesda, MD 20892.
Am J Clin Nutr. 1991 Jan;53(1 Suppl):270S-282S. doi: 10.1093/ajcn/53.1.270S.
Epidemiologic evidence of a protective effect of vitamin C for non-hormone-dependent cancers is strong. Of the 46 such studies in which a dietary vitamin C index was calculated, 33 found statistically significant protection, with high intake conferring approximately a twofold protective effect compared with low intake. Of 29 additional studies that assessed fruit intake, 21 found significant protection. For cancers of the esophagus, larynx, oral cavity, and pancreas, evidence for a protective effect of vitamin C or some component in fruit is strong and consistent. For cancers of the stomach, rectum, breast, and cervix there is also strong evidence. Several recent lung cancer studies found significant protective effects of vitamin C or of foods that are better sources of vitamin C than of beta-carotene. It is likely that ascorbic acid, carotenoids, and other factors in fruits and vegetables act jointly. Increased consumption of fruits and vegetables in general should be encouraged.
维生素C对非激素依赖性癌症具有保护作用的流行病学证据很充分。在46项计算饮食维生素C指数的此类研究中，33项发现具有统计学意义的保护作用，高摄入量与低摄入量相比具有约两倍的保护作用。在另外29项评估水果摄入量的研究中，21项发现有显著保护作用。对于食管癌、喉癌、口腔癌和胰腺癌，维生素C或水果中的某些成分具有保护作用的证据充分且一致。对于胃癌、直肠癌、乳腺癌和宫颈癌也有充分证据。最近的几项肺癌研究发现，维生素C或比β-胡萝卜素更优质的维生素C来源食物具有显著保护作用。水果和蔬菜中的抗坏血酸、类胡萝卜素和其他因素可能共同起作用。总体而言，应鼓励增加水果和蔬菜的摄入量。
