一般认为,60—90%的癌症主要是由外环境因素引起的。外因有多种,其中食物是人们每天接触的外环境物质之一。所谓“病从口入”的谚言便反映了疾病的发生(包括癌症的发生)与食物有密切关系。流行病学的调查研究表明,我国消化道癌症的发病率较高(如胃癌、食管癌、肝癌、结肠癌等),也促使我们去研究膳食与癌症之间的关系。膳食的致癌或抑癌作用可能是通过:(1)膳食中含有直接或间接的致癌物;(2)饮 It is generally believed that 60-90% of cancers are mainly caused by external environmental factors. There are a variety of external causes, of which food is one of the external environmental substances that people touch every day. The rumors of the so-called “sickness from the mouth” reflect that the occurrence of diseases (including the occurrence of cancer) is closely related to food. Epidemiological investigations and studies have shown that the incidence of digestive cancer in China is higher (such as gastric cancer, esophageal cancer, liver cancer, colon cancer, etc.), and it also prompts us to study the relationship between diet and cancer. The carcinogenic or suppressive effects of diet may be through: (1) direct or indirect carcinogens in the diet; (2) drinking