Møller H, Landt J, Pedersen E, Jensen P, Autrup H, Jensen O M
Danish Cancer Registry, Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen.
IARC Sci Publ. 1991(105):168-71.
Several recent case-control studies of gastric cancer have demonstrated the protective effect of consumption of vegetables. According to Correa's model of gastric carcinogenesis, the initiating agent is N-nitroso compounds either ingested or formed in vivo. In our study of endogenous nitrosation, we measured intragastric formation of N-nitroso compounds in 285 individuals by the nitrosation of proline; in this presentation we analysed the effect of consumption of vegetables on urinary excretion of N-nitrosoproline (NPRO). When adjustment was made for the dominating determinants of NPRO excretion (total nitrate intake and tobacco smoking), a marked difference in the effects of consumption of raw and cooled vegetables was seen: consumption of cooked vegetables increased endogenous nitrosation of proline, while consumption of raw vegetables had only a marginal effect. We suggest that the difference between raw and cooked vegetables is due to destruction of ascorbate in the cooking of the vegetables. The lack of a protective effect of consumption of raw vegetables on the rate on endogenous nitrosation of proline indicates, however, that the determinants of nitrosation of proline and the determinants of gastric cancer risk may be different.
最近几项关于胃癌的病例对照研究表明，食用蔬菜具有保护作用。根据科雷亚的胃癌发生模型，起始剂是摄入的或体内形成的N-亚硝基化合物。在我们关于内源性亚硝化作用的研究中，我们通过脯氨酸亚硝化作用测量了285名个体胃内N-亚硝基化合物的形成；在本报告中，我们分析了食用蔬菜对N-亚硝基脯氨酸（NPRO）尿排泄的影响。当对NPRO排泄的主要决定因素（总硝酸盐摄入量和吸烟）进行调整时，生蔬菜和凉拌蔬菜的食用效果存在显著差异：食用熟蔬菜会增加脯氨酸的内源性亚硝化作用，而生蔬菜的食用效果则微乎其微。我们认为生蔬菜和熟蔬菜之间的差异是由于蔬菜烹饪过程中抗坏血酸的破坏。然而，食用生蔬菜对脯氨酸内源性亚硝化作用速率缺乏保护作用表明，脯氨酸亚硝化作用的决定因素和胃癌风险的决定因素可能不同。
