Dietary constituents altering the responses to chemical carcinogens.

This paper deals with two categories of compounds having the capacity to inhibit the neoplastic effects of chemical carcinogens on the host. The first are inducers of increased microsomal mixed function oxidase activity. An increasing number of these inducers are being found in natural products. Cruciferous vegetables including brussels sprouts, cabbage, and cauliflower contain such compounds. Recently indole-3-acetonitrile, indole-3-carbinol and 3,3'-diindolylmethane have been identified as inducers in these three plants. Other naturally occurring inducers include flavones, safrole, isosafrole, beta-ionone, and oxidized sterols. Since previous work has shown that synthetic inducers may protect against chemical carcinogens, the composition of the diet could play a role in inhibiting the neoplastic response to these carcinogenic agents. The second category of inhibitors comprises the antioxidants. Several of these compounds have been found to inhibit the carcinogenic effects of a variety of chemical carcinogens. Considerable work of this nature has been done with butylated hydroxyanisole and butylated hydroxytoluene two antioxidants extensively used as food additives. Other antioxidants having carcinogen inhibiting capacities include ethoxyquin, disulfiram, and dimethyldithiocarbamate.