Dietary Soy Isoflavones for the Prevention of Cancer

OBJECTIVES: I. Determine the effect of varying the dietary intake of soy nuts on plasma levels and urinary excretion of isoflavones. II. Determine the effects of different food composition, along with age and gender of subjects, on plasma levels and urinary excretion of isoflavones.

OUTLINE: This is a two part study. In part I; participants are stratified according to menopausal status. In part II; participants are stratified according to gender and age (under 50 vs. over 50). Part I - Study participants are given 3 different amounts of toasted soy nuts separated by one month intervals. The sequence in which each amount is given is randomized. Blood and urine samples are taken to measure isoflavone levels. Part II - Study participants are given toasted soy nuts, soy milk, and tempeh on separate occasions separated by one month intervals. The sequence of each food is randomized. Blood and urine samples are taken to measure isoflavone levels.

PROJECTED ACCRUAL: 10 women, 5 premenopausal and 5 postmenopausal, will be accrued for part I of the study. 80 subjects, 40 women and 40 men, will be accrued for part II.