膳食、营养与癌症预防的新进展

癌症发生的绝大部分原因是环境因素,因此可以预防。环境因素中除吸烟外主要是膳食和营养因素。膳食脂肪过多引起肥胖,是多种癌症的重要危险因素(乳腺癌与其无明显相关),但科学家们认为今后研究的主攻方向是具体研究不同类脂肪酸的作用。关于膳食抗氧化剂对癌症的保护作用,研究表明-胡萝卜素和维生素C均不理想,人们寄希望于维生素E和硒。总之,在膳食、营养与癌症的关系中,只有蔬菜和水果的保护作用最具有说服力。国际营养学界对膳食指南认识上的方向性转变是:从以营养素为基础的膳食指南转向以食物为基础的膳食指南。并提出了预防癌症的膳食指南建议。

NEW ADVANCES OF DIET, NUTRITION AND CANCER PREVENTION

Most of human cancers are caused by environmental factors; therefore, cancer is preventable. Among the key environmental factors, in addition to tobacco smoking, diet and nutrition play very important roles. Obesity caused by improper diet is the key risk factor for a number of common cancers. However, total fat content of the diet may not be a critical factor and the type of fat and the fatty acid composition of fat in the diet is the focus on dietary fat and cancer. Although there were adequate observational epidemiological evidences on the protective effects of dietary antioxidant nutrients on cancer, intervention trials using beta-carotene and vitamin C did not show positive results. Further studies on vitamin E and selenium are on-going. In the studies on the relationship between diet, nutrition and cancer, the protective effect of fresh fruits and vegetables is most convincing. Recently, the international dietary guidelines on cancer prevention has been shifted from nutrient-based guidelines to food-based guidelines. The publication Diet, Nutrition and Cancer Prevention: a Global Perspective published by WCRF/AICR presents 14 dietary recommendations for the prevention of cancer.