Choi N W, Miller A B, Fodor J G, Jain M, Howe G R, Risch H A, Ruder A M
Department of Epidemiology and Biostatistics, Manitoba Cancer Treatment and Research Foundation, Winnipeg, Canada.
IARC Sci Publ. 1987(84):492-6.
It has been hypothesized that dietary nitrate and nitrite are converted in the stomach to nitrous acid, which reacts with secondary amines and amides to form nitrosamines and nitrosamides, compounds frequently demonstrated to be carcinogenic in animals, and that vitamins C and E inhibit N-nitroso product formation by chemically reducing nitrous acid. This hypothesis and others were tested in a case-control study (controls were individually matched by age, sex and area of residence), utilizing a standardized, quantitative, dietary history questionnaire interview. Daily nutrient consumption values were calculated from interview responses, and continuous conditional logistic regression was used for the data analysis. Significant findings are as follows: (1) Average daily consumption of nitrite, chocolate and carbohydrate was associated with increasing trends in risk. (2) While citrus fruit intake appeared to be somewhat protective, any protective effect of vitamin C intake was less apparent, and of vitamin E, not at all apparent. (3) Consumption of dietary fibre was negatively associated with gastric cancer risk. These findings appear to implicate a number of dietary components, including nitrite consumption, in the genesis of gastric cancer in humans.
据推测，膳食中的硝酸盐和亚硝酸盐在胃中会转化为亚硝酸，亚硝酸会与仲胺和酰胺反应生成亚硝胺和亚硝酰胺，这些化合物在动物实验中经常被证明具有致癌性，同时还推测维生素C和E可通过化学还原亚硝酸来抑制N-亚硝基产物的形成。在一项病例对照研究中（对照组按年龄、性别和居住地区进行个体匹配），利用标准化的定量饮食史问卷调查对这一假设及其他假设进行了检验。根据访谈回答计算出每日营养素摄入量，并采用连续条件逻辑回归进行数据分析。重要发现如下：（1）亚硝酸盐、巧克力和碳水化合物的日均摄入量与风险增加趋势相关。（2）虽然柑橘类水果的摄入量似乎有一定的保护作用，但维生素C摄入量的任何保护作用不太明显，而维生素E的保护作用则完全不明显。（3）膳食纤维的摄入量与胃癌风险呈负相关。这些发现似乎表明，包括亚硝酸盐摄入在内的多种饮食成分与人类胃癌的发生有关。
