CANCER PREVENTIVE IMPACT OF NATURALLY-OCC URRING, NONNUTRITIVE CONSTITUENTS IN FOOD

Numerous epidemiologic studies have shown that a diet rich in vegetabl es, fruits and fiber is associated with a decreased risk of cancer, pa rticularly of epithelial tumors. Especially this association is eviden t for various citrus fruits, carrots, leafy green vegetables, as well as cruciferous- (sorts of cabbage, broccoli) and leak vegetables (garl ic, onions, etc.). In the course of investigation of the protective me chanisms exerted by vegetable foodstuffs, a great number of secondary plant products such as carotenoids, sulfides, glucosinolates, plant st erols, saponins, terpens, phytoestrogens, flavones, protease inhibitor s, or phenolic acids, which are substantial constituents of our daily food, have changed their meaning from a non-nutritive constituent to a probably cancer preventive biological-active substance. But also ferm entable, soluble fibers and substances in fermented foods can exert pr otective effects on development of cancer. Mostly the anticarcinogenic action of biological-active substances is limited to an early stage o f carcinogenesis. Therefore it seems to be important to start preventi on of cancer by nutrition as early as possible and adhere to it over a long period.