POSSIBLE IMMUNOLOGICAL INVOLVEMENT OF ANTIOXIDANTS IN CANCER PREVENTION

The people of Linxian County, China have one of the world's highest ra tes of esophageal cancer. Two intervention trials were conducted to de termine whether supplementation with specific vitamins and minerals co uld lower mortality from or incidence of cancer in this population and whether supplementation with multiple vitamins and minerals would red uce esophageal and gastric cardia cancer in persons with esophageal dy splasia. About 30 000 general population (GP) subjects in the GP trial were randomly assigned to one of eight intervention groups according to a one-half replicate of a 2(4) factorial experimental design and we re supplemented for 5.25 y with four combinations of micronutrients at doses from one to two times the US recommended dietary allowance (RDA ). About 3000 subjects in whom dysplasia was diagnosed in the dysplasi a trial were randomly assigned to groups receiving daily supplementati on with 14 vitamins and 12 minerals at two to three times the US RDA o r placebo for 6 y. Results of the dysplasia trial indicate that in ind ividuals with esophageal dysplasia, micronutrient supplementation had little effect on T lymphocyte responses. In contrast, male participant s in the GP trial who were supplemented with beta-carotene, vitamin E, and selenium showed significantly (P < 0.05) higher mitogenic respons iveness of T lymphocytes in vitro than those not receiving these micro nutrients.