Vogtmann H, Biedermann R
Nutr Health. 1985;3(4):217-39.
It has been demonstrated that nitrates are reduced to nitrites in humans, possibly through bacterial activity. Nitrites, together with ubiquitous amines, can lead to an in-vivo synthesis of carcinogenic nitrosamines. The average daily intake of nitrates depends upon the amount of vegetables consumed and on the nitrate concentration in drinking water. Agricultural practices play an important part in the concentration of nitrate in both water and vegetables. If nitrate is taken up by the plant and not metabolised to amino acids, proteins or nucleic acids, it is stored in cell vacuoles as a reserve. However, with an over-supply of nitrate relative to possible photosynthesis, this stored nitrate is still present at harvest and leads to high concentrations in plant tissue. The nitrate content in plants also depends upon other factors, such as plant variety (cultivar), kind and amount of fertiliser, time of harvest and environmental factors such as light intensity, temperature, etc. It is suggested that we should try to meet the recommendations of toxicologists who believe a dramatic reduction nitrate intake for humans is necessary. It has been demonstrated that modern biological-organic farming methods clearly lead both to lower leaching of nitrates and to lower nitrate content in vegetables. Since no synthetic fungicides are used in this farming method, problems with the reaction of metabolites of such products and nitrites e.g. to highly cancerogenic and multigenic nitroso-ethylenethiourea do not exist.
业已证明，硝酸盐在人体内可被还原为亚硝酸盐，这可能是通过细菌活动实现的。亚硝酸盐与普遍存在的胺类物质一起，可导致体内致癌亚硝胺的合成。硝酸盐的日均摄入量取决于蔬菜的食用量以及饮用水中的硝酸盐浓度。农业生产方式在水和蔬菜中的硝酸盐浓度方面起着重要作用。如果植物吸收了硝酸盐但未代谢为氨基酸、蛋白质或核酸，它就会作为储备储存在细胞液泡中。然而，当硝酸盐供应相对于可能的光合作用过量时，这种储存的硝酸盐在收获时仍然存在，并导致植物组织中硝酸盐浓度升高。植物中的硝酸盐含量还取决于其他因素，如植物品种（栽培品种）、肥料的种类和用量、收获时间以及光照强度、温度等环境因素。有人建议，我们应努力遵循毒理学家的建议，他们认为大幅减少人类硝酸盐摄入量是必要的。业已证明，现代生物有机耕作方法显然既能减少硝酸盐的淋溶，又能降低蔬菜中的硝酸盐含量。由于这种耕作方法不使用合成杀菌剂，因此不存在此类产品的代谢物与亚硝酸盐反应产生的问题，例如不会产生高致癌性和多基因的亚硝基乙撑硫脲。
