目前经实验证实对动物有致癌作用的化学致癌物已多达1000种以上。虽然据国际癌症研究中心调查,经流行病学研究肯定与人类癌症有直接关系的化学致癌物只有30种左右,但事实上对人类有致癌危险的物质决不只这30种,问题是要采用科学方法证实它们对人体确实有致癌作用,在客观上尚存在许多困难。因此一般讨论饮食中存在那些致癌物问题时都是参考动物实验的结果,大部分尚缺乏与人类癌症有直接关系的证据。 Up to now, more than 1,000 chemical carcinogens have been proved to be carcinogenic to animals by experiments. Although there are only about 30 chemical carcinogens that have been directly linked to human cancer through epidemiological studies, according to the International Agency for Research on Cancer, there are more than 30 such substances that are actually carcinogenic to humans. The problem is to adopt science Methods confirm that they do have carcinogenic effects on the human body, there are still many objective difficulties. Therefore, the general discussion of the existence of those carcinogenic substances in the diet are the result of reference to animal experiments, and most still lack evidence of a direct relationship with human cancer.